Java 2实用教程（第三版）
清华大学出版社
（编著 耿祥义 张跃平）
例子源代码

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第一章Java 语言入门
例子1
public class Hello
{
public static void main (String args[ ])
{
System.out.println(“你好，很高兴学习Java”);
}
}
例子2
public class People
{ int height;
String ear;
void speak(String s)
{ System.out.println(s);
}
}
class A
{ public static void main(String args[])
{ People zhubajie;
zhubajie=new People();
zhubajie.height=170;
zhubajie.ear=“两只大耳朵”;
System.out.println(“身高:”+zhubajie.height);
System.out.println(zhubajie.ear);
zhubajie.speak(“师傅，咱们别去西天了，改去月宫吧”);
}
}
例子3
import java.applet.;
import java.awt.;
public class Boy extends Applet
{ public void paint(Graphics g)
{ g.setColor(Color.red);
g.drawString(“我一边喝着咖啡，一边学Java呢”,5,30);
g.setColor(Color.blue);
g.drawString(“我学得很认真”,10,50);
}
}

第二章标识符、关键字和数据类型
例子1
public class Example2_1
{ public static void main (String args[ ])
{ char chinaWord=‘你’,japanWord=‘ぁ’;
int p1=36328,p2=38358;
System.out.println(“汉字’你’在unicode表中的顺序位置:”+(int)chinaWord);
System.out.println(“日语’ぁ’在unicode表中的顺序位置:”+(int)japanWord);
System.out.println(“unicode表中第20328位置上的字符是:”+(char)p1);
System.out.println(“unicode表中第12358位置上的字符是:”+(char)p2);
}
}
例子2
public class Example2_2
{ public static void main (String args[ ])
{ int c=2200;
long d=8000;
float f;
double g=123456789.123456789;
c=(int)d;
f=(float)g; //导致精度的损失.
System.out.print(“c= “+c);
System.out.println(” d= “+d);
System.out.println(“f= “+f);
System.out.println(“g= “+g);
}
}
例子3
public class Example2_3
{ public static void main(String args[])
{ int a[]={100,200,300};
int b[]={10,11,12,13,14,15,16};
b=a;
b[0]=123456;
System.out.println(“数组a:”+a[0]+”,”+a[1]+”,”+a[2]);
System.out.println(“数组b:”+b[0]+”,”+b[1]+","+b[2]);
System.out.println(“数组b的长度:”+b.length);
}
}

第三章运算符、表达式和语句
例子1
class Example3_1
{ public static void main(String args[])
{ char a1=‘十’,a2=‘点’,a3=‘进’,a4=‘攻’;
char secret=‘8’;
a1=(char)(a1^secret);
a2=(char)(a2^secret);
a3=(char)(a3^secret);
a4=(char)(a4^secret);
System.out.println(“密文:”+a1+a2+a3+a4);
a1=(char)(a1^secret);
a2=(char)(a2^secret);
a3=(char)(a3^secret);
a4=(char)(a4^secret);
System.out.println(“原文:”+a1+a2+a3+a4);
}
}
例子2
class Example3_2
{ public static void main(String args[])
{ int x,y=10;
if(((x=0)==0)||((y=20)==20))
{ System.out.println(“现在y的值是:”+y);
}
int a,b=10;
if(((a=0)==0)|((b=20)==20))
{ System.out.println(“现在b的值是:”+b);
}
}
}
例子3
public class Example3_3
{ public static void main(String args[])
{ int a=9,b=5,c=7,t;
if(a>b)
{ t=a; a=b; b=t;
}
if(a>c)
{ t=a; a=c; c=t;
}
if(b>c)
{ t=b; b=c; c=t;
}
System.out.println(“a=”+a+",b="+b+",c="+c);
}
}
例子4
public class Example3_4
{ public static void main(String args[])
{ int math=65 ,english=85;
if(math>60)
{ System.out.println(“数学及格了”);
}
else
{ System.out.println(“数学不及格”);
}
if(english>90)
{ System.out.println(“英语是优”);
}
else
{ System.out.println(“英语不是优”);
}
System.out.println(“我在学习控制语句”);
}
}
例子5
public class Example3_5
{ public static void main(String args[])
{ int x=2,y=1;
switch(x+y)
{ case 1 :
System.out.println(x+y);
break;
case 3:
System.out.println(x+y);
case 0:
System.out.println(x+y);
break;
default: System.out.println(“没有般配的”+(x+y));
}
}
}
例子6
public class Example3_6
{ public static void main(String args[])
{ long sum=0,a=5,item=a,n=10,i=1;
for(i=1;i<=n;i++)
{ sum=sum+item;
item=item*10+a;
}
System.out.println(sum);
}
}

例子7
class Example3_7
{ public static void main(String args[])
{ double sum=0,a=1;
int i=1;
while(i<=20)
{ sum=sum+a;
i=i+1;
a=a*(1.0/i);
}
System.out.println(“sum=”+sum);
}
}
例子8
class Example3_8
{ public static void main(String args[])
{ int sum=0,i,j;
for( i=1;i<=10;i++)
{ if(i%20) //计算1+3+5+7+9
continue;
sum=sum+i;
}
System.out.println(“sum=”+sum);
for(j=2;j<=50;j++) //求50以内的素数
{ for( i=2;i<=j/2;i++)
{ if(j%i0)
break;
}
if(i>j/2)
{ System.out.println(""+j+“是素数”);
}
}
}
}

第四章类、对象和接口
例子1
class XiyoujiRenwu
{ float height,weight;
String head, ear,hand,foot, mouth;
void speak(String s)
{ System.out.println(s);
}
}
class A
{ public static void main(String args[])
{ XiyoujiRenwu zhubajie; //声明对象
zhubajie=new XiyoujiRenwu(); //为对象分配内存，使用new 运算符和默认的构造方法
}
}
例子2
class Point
{ int x,y;
Point(int a,int b)
{ x=a;
y=b;
}
}
public class A
{ public static void main(String args[])
{ Point p1,p2; //声明对象p1和p2
p1=new Point(10,10); //为对象分配内存，使用 new 和类中的构造方法
p2=new Point(23,35); //为对象分配内存，使用 new 和类中的构造方法
}
}
例子3
class XiyoujiRenwu
{ float height,weight;
String head, ear,hand,foot,mouth;
void speak(String s)
{ head=“歪着头”;
System.out.println(s);
}
}
class Example4_3
{ public static void main(String args[])
{ XiyoujiRenwu zhubajie,sunwukong;//声明对象
zhubajie=new XiyoujiRenwu(); //为对象分配内存
sunwukong=new XiyoujiRenwu();
zhubajie.height=1.80f; //对象给自己的变量赋值
zhubajie.head=“大头”;
zhubajie.ear=“一双大耳朵”;
sunwukong.height=1.62f; //对象给自己的变量赋值
sunwukong.weight=1000f;
sunwukong.head=“绣发飘飘”;
System.out.println(“zhubajie的身高：”+zhubajie.height);
System.out.println(“zhubajie的头：”+zhubajie.head);
System.out.println(“sunwukong的重量：”+sunwukong.weight);
System.out.println(“sunwukong的头：”+sunwukong.head);
zhubajie.speak(“俺老猪我想娶媳妇”); //对象调用方法
System.out.println(“zhubajie现在的头：”+zhubajie.head);
sunwukong.speak(“老孙我重1000斤，我想骗八戒背我”); //对象调用方法
System.out.println(“sunwukong现在的头：”+sunwukong.head);
}
}
例子4
class 梯形
{ float 上底,下底,高,面积;
梯形(float x,float y,float h)
{ 上底=x;
下底=y;
高=h;
}
float 计算面积()
{ 面积=(上底+下底)高/2.0f;
return 面积;
}
void 修改高(float height)
{ 高=height;
}
float 获取高()
{ return 高;
}
}
public class Example4_4
{ public static void main(String args[])
{ 梯形 laderOne=new 梯形(12.0f,3.5f,50),laderTwo=new 梯形(2.67f,3.0f,10);
System.out.println(“laderOne的高是:”+laderOne.获取高());
System.out.println(“laderTwo的高是:”+laderTwo.获取高());
System.out.println(“laderOne的面积是:”+laderOne.计算面积());
System.out.println(“laderTwo的面积是:”+laderTwo.计算面积());
laderOne.修改高(10);
float h=laderOne.获取高();
laderTwo.修改高(h2);
System.out.println(“laderOne现在的高是:”+laderOne.获取高());
System.out.println(“laderTwo现在的高是:”+laderTwo.获取高());
System.out.println(“laderOne现在的面积是:”+laderOne.计算面积());
System.out.println(“laderTwo现在的面积是:”+laderTwo.计算面积());
}
}
例子5
class People
{ String face;
void setFace(String s)
{ face=s;
}
}
class A
{ void f(int x,double y,People p)
{ x=x+1;
y=y+1;
p.setFace(“笑脸”);
System.out.println(“参数x和y的值分别是:”+x+","+y);
System.out.println(“参数对象p的face是:”+p.face);
}
}
public class Example4_5
{ public static void main(String args[])
{ int x=100;
double y=100.88;
People zhang=new People();
zhang.setFace(“很严肃的样子”);
A a=new A();
a.f(x,y,zhang);
System.out.println(“main方法中x和y的值仍然分别是:”+x+","+y);
System.out.println(“main方法中对象zhang的face是:”+zhang.face);
}
}
例子6
class 圆
{ double 半径;
圆(double r)
{ 半径=r;
}
double 计算面积()
{ return 3.14半径半径;
}
void 修改半径(double 新半径)
{ 半径=新半径;
}
double 获取半径()
{ return 半径;
}
}
class 圆锥
{ 圆 底圆;
double 高;
圆锥(圆 circle,double h)
{ this.底圆=circle;
this.高=h;
}
double 计算体积()
{ double volume;
volume=底圆.计算面积()高/3.0;
return volume;
}
void 修改底圆半径(double r)
{ 底圆.修改半径®;
}
double 获取底圆半径()
{ return 底圆.获取半径();
}
}
class Example4_6
{ public static void main(String args[])
{ 圆 circle=new 圆(10);
圆锥 circular=new 圆锥(circle,20);
System.out.println(“圆锥底圆半径:”+circular.获取底圆半径());
System.out.println(“圆锥的体积:”+circular.计算体积());
circular.修改底圆半径(100);
System.out.println(“圆锥底圆半径:”+circular.获取底圆半径());
System.out.println(“圆锥的体积:”+circular.计算体积());
}
}
例子7
class 梯形
{ float 上底,高;
static float 下底;
梯形(float x,float y,float h)
{ 上底=x; 下底=y; 高=h;
}
float 获取下底()
{ return 下底;
}
void 修改下底(float b)
{ 下底=b;
}
}
class Example4_7
{ public static void main(String args[])
{ 梯形 laderOne=new 梯形(3.0f,10.0f,20),laderTwo=new 梯形(2.0f,3.0f,10);
梯形.下底=200; //通过类名操作类变量
System.out.println(“laderOne的下底:”+laderOne.获取下底());
System.out.println(“laderTwo的下底:”+laderTwo.获取下底());
laderTwo.修改下底(60); //通过对象操作类变量
System.out.println(“laderOne的下底:”+laderOne.获取下底());
System.out.println(“laderTwo的下底:”+laderTwo.获取下底());
}
}
例子8
class Fibi
{ public static long fibinacii(int n)
{ long c=0;
if(n1||n2)
c=1;
else
c=fibinacii(n-1)+fibinacii(n-2);
return c;
}
}
public class Example4_8
{ public static void main(String args[])
{ System.out.println(Fibi.fibinacii(7));
}
}
例子9
package tom.jiafei;
public class PrimNumber
{ public void getPrimnumber(int n)
{ int sum=0,i,j;
for(i=1;i<=n;i++)
{ for(j=2;j<=i/2;j++)
{ if(i%j==0)
break;
}
if(j>i/2)
System.out.print(" "+i);
}
}
public static void main(String args[])
{ PrimNumber p=new PrimNumber();
p.getPrimnumber(20);
}
}
例子10
import java.applet.Applet;
import java.awt.;
public class Example4_10 extends Applet
{ Button redbutton;
public void init()
{ redbutton=new Button(“我是一个红色的按钮”);
redbutton.setBackground(Color.red);
redbutton.setForeground(Color.white);
add(redbutton);
}
}
例子11
import tom.jiafei.; //引入包tom.jiafei中的类
public class Example4_11
{ public static void main(String args[])
{ PrimNumber num=new PrimNumber();//用包tom.jiafei中的类创建对象
num.getPrimnumber(30);
}
}
例子12
public class Example4_12
{ public static void main(String args[])
{ PrimNumber num=new PrimNumber();//要保证PrimNuber类和Example4_12类在同一目录中
num.getPrimnumber(120);
}
}
Trangel.java
package tom.jiafei;
public class Trangle
{ double sideA,sideB,sideC;
boolean boo;
public Trangle(double a,double b,double c)
{ sideA=a;
sideB=b;
sideC=c;
if(a+b>c&&a+c>b&&c+b>a)
{ System.out.println(“我是一个三角形”);
boo=true;
}
else
{ System.out.println(“我不是一个三角形”);
boo=false;
}
}
public void 计算面积()
{ if(boo)
{ double p=(sideA+sideB+sideC)/2.0;
double area=Math.sqrt(p(p-sideA)(p-sideB)(p-sideC)) ;
System.out.println(“面积是:”+area);
}
else
{ System.out.println(“不是一个三角形,不能计算面积”);
}
}
public void 修改三边(double a,double b,double c)
{ sideA=a;
sideB=b;
sideC=c;
if(a+b>c&&a+c>b&&c+b>a)
{ boo=true;
}
else
{ boo=false;
}
}
}
例子13
import tom.jiafei.Trangle;
class Example4_13
{ public static void main(String args[])
{ Trangle trangle=new Trangle(12,3,1);
trangle.计算面积();
trangle.修改三边(3,4,5);
trangle.计算面积();
}
}
例子14
class Example4_14
{ private int money;
Example4_14()
{ money=2000;
}
private int getMoney()
{ return money;
}
public static void main(String args[])
{ Example4_14 exa=new Example4_14();
exa.money=3000;
int m=exa.getMoney();
System.out.println(“money=”+m);
}
}
例子15
class Father
{ private int money;
float weight,height;
String head;
void speak(String s)
{ System.out.println(s);
}
}
class Son extends Father
{ String hand,foot;
}
public class Example4_15
{ public static void main(String args[])
{ Son boy;
boy=new Son();
boy.weight=1.80f;
boy.height=120f;
boy.head=“一个头”;
boy.hand=“两只手 “;
boy.foot=“两只脚”;
boy.speak(“我是儿子”);
System.out.println(boy.hand+boy.foot+boy.head+boy.weight+boy.height);
}
}
例子16
class Chengji
{ float f(float x,float y)
{ return xy;
}
}
class Xiangjia extends Chengji
{ float f(float x,float y)
{ return x+y ;
}
}
public class Example4_16
{ public static void main(String args[])
{ Xiangjia sum;
sum=new Xiangjia();
float c=sum.f(4,6);
System.out.println©;
}
}
例子17
class Area
{ float f(float r )
{ return 3.14159frr;
}
float g(float x,float y)
{ return x+y;
}
}
class Circle extends Area
{ float f(float r)
{ return 3.14159f2.0fr;
}
}
public class Example4_17
{ public static void main(String args[])
{ Circle yuan;
yuan=new Circle();
float length=yuan.f(5.0f);
float sum=yuan.g(232.645f,418.567f);
System.out.println(length);
System.out.println(sum);
}
}
例子18
class A
{
final double PI=3.1415926;
public double getArea(final double r)
{
return PIrr;
}
}
public class Example4_18
{ public static void main(String args[])
{ A a=new A();
System.out.println(“面积：”+a.getArea(100));
}
}
例子19
class 类人猿
{ private int n=100;
void crySpeak(String s)
{ System.out.println(s);
}
}
class People extends 类人猿
{ void computer(int a,int b)
{ int c=ab;
System.out.println©;
}
void crySpeak(String s)
{ System.out.println(”"+s+"”);
}
}
class Example4_19
{ public static void main(String args[])
{ 类人猿 monkey=new People();
monkey.crySpeak(“I love this game”);
People people=(People)monkey;
people.computer(10,10);
}
}
例子20
class 动物
{ void cry()
{
}
}
class 狗 extends 动物
{ void cry()
{ System.out.println(“汪汪…”);
}
}
class 猫 extends 动物
{ void cry()
{ System.out.println(“喵喵…”);
}
}
class Example4_20
{ public static void main(String args[])
{ 动物 dongwu;
dongwu=new 狗();
dongwu.cry();
dongwu=new 猫();
dongwu.cry();
}
}

例子21
abstract class A
{ abstract int min(int x,int y);
int max(int x,int y)
{ return x>y?x:y;
}
}
class B extends A
{ int min(int x,int y)
{ return x<y?x:y;
}
}
public class Example4_21
{ public static void main(String args[])
{ A a;
B b=new B();
int max=b.max(12,34);
int min=b.min(12,34);
System.out.println(“max=”+max+" min="+min);
a=b;
max=a.max(12,34);
System.out.println(“max=”+max);
}
}
例子22
abstract class 图形
{ public abstract double 求面积();
}
class 梯形 extends 图形
{ double a,b,h;
梯形(double a,double b,double h)
{ this.a=a;
this.b=b;
this.h=h;
}
public double 求面积()
{ return((1/2.0)(a+b)h);
}
}
class 圆形 extends 图形
{ double r;
圆形(double r)
{ this.r=r;
}
public double 求面积()
{ return(3.14rr);
}
}
class 堆
{ 图形 底;
double 高;
堆(图形 底,double 高)
{ this.底=底;
this.高=高;
}
void 换底(图形 底)
{ this.底=底;
}
public double 求体积()
{ return (底.求面积()高)/3.0;
}
}
public class Example4_22
{ public static void main(String args[])
{ 堆 zui;
图形 tuxing;
tuxing=new 梯形(2.0,7.0,10.7);
System.out.println(“梯形的面积”+tuxing.求面积());
zui=new 堆(tuxing,30);
System.out.println(“梯形底的堆的体积”+zui.求体积());
tuxing=new 圆形(10);
System.out.println(“半径是10的圆的面积”+tuxing.求面积());
zui.换底(tuxing);
System.out.println(“圆形底的堆的体积”+zui.求体积());
}
}
例子23
class Student
{ int number;String name;
Student()
{
}
Student(int number,String name)
{ this.number=number;
this.name=name;
System.out.println("I am "+name+ "my number is "+number);
}
}
class Univer_Student extends Student
{ boolean 婚否;
Univer_Student(int number,String name,boolean b)
{ super(number,name);
婚否=b;
System.out.println(“婚否=”+婚否);
}
}
public class Example4_23
{ public static void main(String args[])
{ Univer_Student zhang=new Univer_Student(9901,“和晓林”,false);
}
}
例子24
class Sum
{ int n;
float f()
{ float sum=0;
for(int i=1;i<=n;i++)
sum=sum+i;
return sum;
}
}
class Average extends Sum
{ int n;
float f()
{ float c;
super.n=n;
c=super.f();
return c/n;
}
float g()
{ float c;
c=super.f();
return c/2;
}
}
public class Example4_24
{ public static void main(String args[])
{ Average aver=new Average();
aver.n=100;
float result_1=aver.f();
float result_2=aver.g();
System.out.println(“result_1=”+result_1);
System.out.println(“result_2=”+result_2);
}
}
例子25
interface Computable
{ int MAX=100;
int f(int x);
}
class China implements Computable
{ int number;
public int f(int x) //不要忘记public关键字
{ int sum=0;
for(int i=1;i<=x;i++)
{ sum=sum+i;
}
return sum;
}
}
class Japan implements Computable
{ int number;
public int f(int x)
{ return 44+x;
}
}
public class Example4_25
{ public static void main(String args[])
{ China zhang;
Japan henlu;
zhang=new China();
henlu=new Japan();
zhang.number=991898+Computable.MAX;
henlu.number=941448+Computable.MAX;
System.out.println(“number:”+zhang.number+“求和”+zhang.f(100));
System.out.println(“number:”+henlu.number+“求和”+henlu.f(100));
}
}
例子26
interface 收费
{ public void 收取费用();
}
interface 调节温度
{ public void controlTemperature();
}
class 公共汽车 implements 收费
{ public void 收取费用()
{ System.out.println(“公共汽车:一元/张,不计算公里数”);
}
}
class 出租车 implements 收费, 调节温度
{ public void 收取费用()
{ System.out.println(“出租车:1.60元/公里,起价3公里”);
}
public void controlTemperature()
{ System.out.println(“安装了Hair空调”);
}
}
class 电影院 implements 收费,调节温度
{ public void 收取费用()
{ System.out.println(“电影院:门票,十元/张”);
}
public void controlTemperature()
{ System.out.println(“安装了中央空调”);
}
}
class Example4_26
{ public static void main(String args[])
{ 公共汽车 七路=new 公共汽车();
出租车 天宇=new 出租车();
电影院 红星=new 电影院();
七路.收取费用();
天宇.收取费用();
红星.收取费用();
天宇.controlTemperature();
红星.controlTemperature();
}
}
例子27
interface ShowMessage
{ void 显示商标(String s);
}
class TV implements ShowMessage
{ public void 显示商标(String s)
{ System.out.println(s);
}
}
class PC implements ShowMessage
{ public void 显示商标(String s)
{ System.out.println(s);
}
}
public class Example4_27
{ public static void main(String args[])
{ ShowMessage sm;
sm=new TV();
sm.显示商标(“长城牌电视机”);
sm=new PC();
sm.显示商标(“联想奔月5008PC机”);
}
}
例子28
interface Computerable
{ public double 求面积();
}
class 梯形 implements Computerable
{ double a,b,h;
梯形(double a,double b,double h)
{ this.a=a;
this.b=b;
this.h=h;
}
public double 求面积()
{ return((1/2.0)(a+b)h);
}
}
class 圆形 implements Computerable
{ double r;
圆形(double r)
{ this.r=r;
}
public double 求面积()
{ return(3.14rr);
}
}
class 堆
{ Computerable 底;
double 高;
堆(Computerable 底,double 高)
{ this.底=底;
this.高=高;
}
void 换底(Computerable 底)
{ this.底=底;
}
public double 求体积()
{ return (底.求面积()高)/3.0;
}
}
public class Example4_28
{ public static void main(String args[])
{ 堆 zui;
Computerable bottom;
bottom=new 梯形(2.0,7.0,10.7);
System.out.println(“梯形的面积”+bottom.求面积());
zui=new 堆(bottom,30);
System.out.println(“梯形底的堆的体积”+zui.求体积());
bottom=new 圆形(10);
System.out.println(“半径是10的圆的面积”+bottom.求面积());
zui.换底(bottom);
System.out.println(“圆形底的堆的体积”+zui.求体积());
}
}
例子29
interface SpeakHello
{ void speakHello();
}
class Chinese implements SpeakHello
{ public void speakHello()
{ System.out.println("中国人习惯问候语：你好，吃饭了吗？ ");
}
}
class English implements SpeakHello
{ public void speakHello()
{ System.out.println(“英国人习惯问候语：你好，天气不错 “);
}
}
class KindHello
{ public void lookHello(SpeakHello hello)
{ hello.speakHello();
}
}
public class Example4_29
{ public static void main(String args[])
{ KindHello kindHello=new KindHello();
kindHello.lookHello(new Chinese());
kindHello.lookHello(new English());
}
}
例子30
class China
{ final String nationalAnthem=“义勇军进行曲”;
Beijing beijing;
China()
{ beijing=new Beijing();
}
String getSong()
{ return nationalAnthem;
}
class Beijing
{ String name=“北京”;
void speak()
{ System.out.println(“我们是”+name+” 我们的国歌是:”+getSong());
}
}
}
public class Example4_30
{ public static void main(String args[])
{ China china=new China();
china.beijing.speak();
}
}
例子31
class Cubic
{ double getCubic(int n)
{ return 0;
}
}
abstract class Sqrt
{ public abstract double getSqrt(int x);
}
class A
{ void f(Cubic cubic)
{ double result=cubic.getCubic(3);
System.out.println(result);
}
}
public class Example4_31
{ public static void main(String args[])
{ A a=new A();
a.f(new Cubic()
{ double getCubic(int n)
{ return nnn;
}
}
);
Sqrt ss=new Sqrt()
{ public double getSqrt(int x)
{ return Math.sqrt(x);
}
};
double m=ss.getSqrt(5);
System.out.println(m);
}
}
例子32
interface Cubic
{ double getCubic(int n);
}
interface Sqrt
{ public double getSqrt(int x);
}
class A
{ void f(Cubic cubic)
{ double result=cubic.getCubic(3);
System.out.println(result);
}
}
public class Example4_32
{ public static void main(String args[])
{ A a=new A();
a.f(new Cubic()
{ public double getCubic(int n)
{ return nnn;
}
}
);
Sqrt ss=new Sqrt()
{ public double getSqrt(int x)
{ return Math.sqrt(x);
}
};
double m=ss.getSqrt(5);
System.out.println(m);
}
}
例子33
public class Example4_33
{ public static void main(String args[ ])
{ int n=0,m=0,t=555;
try{ m=Integer.parseInt(“8888”);
n=Integer.parseInt(“abc789”);
t=9999;
}
catch(NumberFormatException e)
{ System.out.println(“发生异常:”+e.getMessage());
e.printStackTrace();
n=123;
}
System.out.println(“n=”+n+",m="+m+",t="+t);
}
}
例子34
class NopositiveException extends Exception
{ String message;
NopositiveException(int m,int n)
{ message=“数字”+m+“或”+n+“不是正整数”;
}
public String toString()
{ return message;
}
}
class Computer
{ public int getMaxCommonDivisor(int m,int n) throws NopositiveException
{ if(n<=0||m<=0)
{ NopositiveException exception=new NopositiveException(m,n);
throw exception;
}
if(m<n)
{ int temp=0;
temp=m;
m=n;
n=temp;
}
int r=m%n;
while(r!=0)
{ m=n;
n=r;
r=m%n;
}
return n;
}
}
public class Example4_34
{ public static void main(String args[])
{ int m=24,n=36,result=0;
Computer a=new Computer();
try { result=a.getMaxCommonDivisor(m,n);
System.out.println(m+“和”+n+"的最大公约数 "+result);
m=-12;
n=22;
result=a.getMaxCommonDivisor(m,n);
System.out.println(m+“和”+n+"的最大公约数 “+result);
}
catch(NopositiveException e)
{ System.out.println(e.toString());
}
}
}
例子35
import java.lang.reflect.;
class Rect
{ double width,height,area;
public double getArea()
{ area=heightwidth;
return area;
}
}
public class Example4_35
{ public static void main(String args[])
{ Rect rect=new Rect();
Class cs=rect.getClass();
String className=cs.getName();
Constructor[] con=cs.getDeclaredConstructors();
Field[] field=cs.getDeclaredFields() ;
Method[] method=cs.getDeclaredMethods();
System.out.println(“类的名字:”+className);
System.out.println(“类中有如下的成员变量:”);
for(int i=0;i<field.length;i++)
{ System.out.println(field[i].toString());
}
System.out.println(“类中有如下的方法:”);
for(int i=0;i<method.length;i++)
{ System.out.println(method[i].toString());
}
System.out.println(“类中有如下的构造方法:”);
for(int i=0;i<con.length;i++)
{ System.out.println(con[i].toString());
}
}
}
例子36
class Rect
{ double width,height,area;
public double getArea()
{ area=height*width;
return area;
}
}
public class Example4_36
{ public static void main(String args[])
{ try{ Class cs=Class.forName(“Rect”);
Rect rect=(Rect)cs.newInstance();
rect.width=100;
rect.height=200;
System.out.println(“rect的面积”+rect.getArea());
}
catch(Exception e){}
}
}
例子37
public class Example4_37
{ public static void main(String args[ ])
{ char a[]={‘a’,‘b’,‘c’,‘D’,‘E’,‘F’};
for(int i=0;i<a.length;i++)
{ if(Character.isLowerCase(a[i]))
{ a[i]=Character.toUpperCase(a[i]);
}
else if(Character.isUpperCase(a[i]))
{ a[i]=Character.toLowerCase(a[i]);
}
}
for(int i=0;i<a.length;i++)
{ System.out.print(” "+a[i]);
}
}
}
Mymoon.mf
Manifest-Version: 1.0
Main-Class: A
Created-By: 1.4(Sun Microsystems Inc.)
Test1.java
public class Test1
{ public void fTest1()
{ System.out.println(“I am a method In Test1 class”);
}
}
Test2.java
public class Test2
{ public void fTest2()
{ System.out.println(“I am a method In Test2 class”);
}
}
moon.mf
Manifest-Version: 1.0
Class: Test1 Test2
Created-By: 1.4(Sun Microsystems Inc.)

第五章字符串
例子1
class Example5_1
{ public static void main(String args[])
{ String s1,s2;
s1=new String(“we are students”);
s2=new String(“we are students”);
System.out.println(s1.equals(s2));
System.out.println(s1s2);
String s3,s4;
s3=“how are you”;
s4=“how are you”;
System.out.println(s3.equals(s4));
System.out.println(s3s4);
}
}
例子2
class Example5_2
{ public static void main(String args[])
{ int number=0;
String s=“student;entropy;engage,english,client”;
for(int k=0;k<s.length();k++)
{ if(s.regionMatches(k,“en”,0,2))
{ number++;
}
}
System.out.println(“number=”+number);
}
}
例子3
class Example5_3
{ public static void main(String args[])
{ String a[]={“door”,“apple”,“Applet”,“girl”,“boy”};
for(int i=0;i<a.length-1;i++)
{ for(int j=i+1;j<a.length;j++)
{ if(a[j].compareTo(a[i])<0)
{ String temp=a[i];
a[i]=a[j];
a[j]=temp;
}
}
}
for(int i=0;i<a.length;i++)
{ System.out.print(" “+a[i]);
}
}
}
例子4
class Example5_4
{ public static void main(String args[])
{ String path=“c:\myfile\2000\result.txt”;
int index=path.lastIndexOf(”\");
String fileName=path.substring(index+1);
String newName=fileName.replaceAll(".txt",".java");
System.out.println(path);
System.out.println(fileName);
System.out.println(newName);
}
}

例子5
public class Example5_5
{ public static void main(String args[])
{ double n,sum=0,item=0;
boolean computable=true;
for(int i=0;i<args.length;i++)
{ try{ item=Double.parseDouble(args[i]);
sum=sum+item;
}
catch(NumberFormatException e)
{ System.out.println(“您键入了非数字字符:”+e);
computable=false;
}
}
if(computable)
{ n=sum/args.length;
System.out.println(“平均数:”+n);
}
int number=123456;
String binaryString=Long.toBinaryString(number);
System.out.println(number+“的二进制表示:”+binaryString);
System.out.println(number+“的十六进制表示:”+Long.toString(number,16));
String str=“1110110”;
int p=0,m=0;
for(int i=str.length()-1;i>=0;i–)
{ char c=str.charAt(i);
int a=Integer.parseInt(""+c);
p=p+(int)(aMath.pow(2,m));
m++;
}
System.out.println(str+“的十进制表示:”+p);
}
}
例子6
import java.util.Date;
import java.awt.;
public class Example5_6
{ public static void main(String args[])
{ Date date=new Date();
Button button=new Button(“确定”);
System.out.println(date.toString());
System.out.println(button.toString());
}
}
例子7
import java.util.*;
public class Example5_7
{ public static void main(String args[])
{ String s=“I am Geng.X.y,she is my girlfriend”;
StringTokenizer fenxi=new StringTokenizer(s," ,");
int number=fenxi.countTokens();
while(fenxi.hasMoreTokens())
{ String str=fenxi.nextToken();
System.out.println(str);
System.out.println(“还剩”+fenxi.countTokens()+“个单词”);
}
System.out.println(“s共有单词：”+number+“个”);
}
}
例子8
class Example5_8
{ public static void main(String args[])
{ char c[],d[];
String s=“巴西足球队击败德国足球队”;
c=new char[2];
s.getChars(5,7,c,0);
System.out.println©;
d=new char[s.length()];
s.getChars(7,12,d,0);
s.getChars(5,7,d,5);
s.getChars(0,5,d,7);
System.out.println(d);
}
}
例子9
class Example5_9
{ public static void main(String args[])
{ String s=“清华大学出版社”;
char a[]=s.toCharArray();
for(int i=0;i<a.length;i++)
{ a[i]=(char)(a[i]^‘t’);
}
String secret=new String(a);
System.out.println(“密文:”+secret);
for(int i=0;i<a.length;i++)
{ a[i]=(char)(a[i]^‘t’);
}
String code=new String(a);
System.out.println(“原文:”+code);
}
}
例子10
public class Example5_10
{ public static void main(String args[])
{ byte d[]=“你我他”.getBytes();
System.out.println(“数组d的长度是(一个汉字占两个字节):”+d.length);
String s=new String(d,0,2);
System.out.println(s);
}
}
例子11
class Example5_11
{ public static void main(String args[ ])
{ StringBuffer str=new StringBuffer(“62791720”);
str.insert(0,“010-”);
str.setCharAt(7 ,‘8’);
str.setCharAt(str.length()-1,‘7’);
System.out.println(str);
str.append("-446");
System.out.println(str);
str.reverse();
System.out.println(str);
}
}
例子12
public class Example5_12
{ public static void main (String args[ ])
{
String regex="\w{1,}@\w{1,}\56\w{1,}" ;
String str1=“zhangsan@sina.com”;
String str2=“li@si@dl.cn”;
if(str1.matches(regex))
{ System.out.println(str1+“是一个Email地址”);
}
else
{ System.out.println(str1+“不是一个Email地址”);
}
if(str2.matches(regex))
{ System.out.println(str2+“是一个Email地址”);
}
else
{ System.out.println(str2+“不是一个Email地址”);
}
}
}

第六章时间、日期和数字
例子1
import java.util.Date;
import java.text.SimpleDateFormat;
class Example6_1
{ public static void main(String args[])
{ Date nowTime=new Date();
System.out.println(nowTime);
SimpleDateFormat matter1=
new SimpleDateFormat(" ‘time’:yyyy年MM月dd日E 北京时间");
System.out.println(matter1.format(nowTime));
SimpleDateFormat matter2=
new SimpleDateFormat(“北京时间:yyyy年MM月dd日HH时mm分ss秒”);
System.out.println(matter2.format(nowTime));
Date date1=new Date(1000),
date2=new Date(-1000);
System.out.println(matter2.format(date1));
System.out.println(matter2.format(date2));
System.out.println(new Date(System.currentTimeMillis()));
}
}
例子2
import java.util.;
class Example6_2
{ public static void main(String args[])
{ Calendar calendar=Calendar.getInstance();
calendar.setTime(new Date());
String 年=String.valueOf(calendar.get(Calendar.YEAR)),
月=String.valueOf(calendar.get(Calendar.MONTH)+1),
日=String.valueOf(calendar.get(Calendar.DAY_OF_MONTH)),
星期=String.valueOf(calendar.get(Calendar.DAY_OF_WEEK)-1);
int hour=calendar.get(Calendar.HOUR_OF_DAY),
minute=calendar.get(Calendar.MINUTE),
second=calendar.get(Calendar.SECOND);
System.out.println(“现在的时间是：”);
System.out.println(""+年+“年”+月+“月”+日+“日 “+ “星期”+星期);
System.out.println(””+hour+“时”+minute+“分”+second+“秒”);
calendar.set(1962,5,29); //将日历翻到1962年6月29日,注意5表示六月。
long time1962=calendar.getTimeInMillis();
calendar.set(2006,9,1);
long time2006=calendar.getTimeInMillis();
long 相隔天数=(time2006-time1962)/(1000606024);
System.out.println(“2006年10月1日和1962年6月29日相隔”+相隔天数+“天”);
}
}
例子3
import java.util.;
class Example6_3
{ public static void main(String args[])
{ System.out.println(" 日 一 二 三 四 五 六");
Calendar 日历=Calendar.getInstance();
日历.set(2006,11,1); //将日历翻到2006年12月1日。
int 星期几=日历.get(Calendar.DAY_OF_WEEK)-1;
String a[]=new String[星期几+31];
for(int i=0;i<星期几;i++)
{ a[i]="**";
}
for(int i=星期几,n=1;i<星期几+31;i++)
{ if(n<=9)
a[i]=String.valueOf(n)+" “;
else
a[i]=String.valueOf(n) ;
n++;
}
for(int i=0;i<a.length;i++)
{ if(i%70)
{ System.out.println("");
}
System.out.print(" “+a[i]);
}
}
}
例子4
import java.text.NumberFormat;
class Example6_4
{ public static void main(String args[])
{ double a=Math.sqrt(5);
System.out.println(“格式化前：”+a);
NumberFormat f=NumberFormat.getInstance();
f.setMaximumFractionDigits(7);
f.setMinimumIntegerDigits(3);
String s=f.format(a);
System.out.println(“格式化后：”+s);
MyNumberFormat myFormat=new MyNumberFormat();
System.out.println(“格式化后：”+myFormat.format(a,4));
System.out.println(“得到的随机数：”);
int number=8;
for(int i=1;i<=20;i++)
{ int randomNumber=(int)(Math.random()*number)+1;
System.out.print(” "+randomNumber);
if(i%100)
System.out.println(”");
}
}
}
class MyNumberFormat
{ public String format(double a,int n)
{ String str=String.valueOf(a);
int index=str.indexOf(".");
String temp=str.substring(index+1);
int leng=0;
leng=temp.length();
int min=Math.min(leng,n);
str=str.substring(0,index+min+1);
return str;
}
}
}
例子5
import java.math.;
public class Example6_5
{ public static void main(String args[])
{ BigInteger sum=new BigInteger(“0”),
xiang=new BigInteger(“1”),
ONE=new BigInteger(“1”),
i=ONE,
m=new BigInteger(“30”);
while(i.compareTo(m)<=0)
{ sum=sum.add(xiang);
i=i.add(ONE);
xiang=xiang.multiply(i);
}
System.out.println(sum);
}
}

第七章AWT组件及事件处理
例子1
import java.awt.;
class FirstWindow extends Frame
{ MenuBar menubar;
Menu menu;
MenuItem item1,item2;
FirstWindow(String s)
{ setTitle(s);
Toolkit tool=getToolkit();
Dimension dim=tool.getScreenSize();
setBounds(0,0,dim.width,dim.height/2);
menubar=new MenuBar();
menu=new Menu(“文件”);
item1=new MenuItem(“打开”);
item2=new MenuItem(“保存”);
menu.add(item1);
menu.add(item2);
menubar.add(menu);
setMenuBar(menubar);
setVisible(true);
}
}
public class Example7_1
{ public static void main(String args[])
{ FirstWindow win=new FirstWindow(“一个带菜单的窗口”);
}
}
例子2
import java.awt.;
class WindowText extends Frame
{ TextField text1,text2;
WindowText(String s)
{ super(s);
setLayout(new FlowLayout());
text1=new TextField(“输入密码：”,10);
text1.setEditable(false);
text2=new TextField(10);
text2.setEchoChar(’’);
add(text1);
add(text2);
setBounds(100,100,200,150);
setVisible(true);
validate();
}
}
public class Example7_2
{ public static void main(String args[])
{ WindowText win=new WindowText(“添加了文本框的窗口”);
}
}
例子3
import java.awt.;
import java.awt.event.;
class MyWindow extends Frame implements ActionListener
{ TextField text1,text2,text3;
MyWindow()
{ setLayout(new FlowLayout());
text1=new TextField(8);
text2=new TextField(8);
text3=new TextField(15);
add(text1);
add(text2);
add(text3);
text1.addActionListener(this);
text2.addActionListener(this);
setBounds(100,100,150,150);
setVisible(true);
validate();
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()==text1)
{ String word=text1.getText();
if(word.equals(“boy”))
{ text3.setText(“男孩”);
}
else if (word.equals(“girl”))
{ text3.setText(“女孩”);
}
else if (word.equals(“sun”))
{ text3.setText(“太阳”);
}
else
{ text3.setText(“没有该单词”);
}
}
else if(e.getSource()==text2)
{ String word=text2.getText();
if(word.equals(“男孩”))
{ text3.setText(“boy”);
}
else if (word.equals(“女孩”))
{ text3.setText(“girl”);
}
else if (word.equals(“太阳”))
{ text3.setText(“sun”);
}
else
{ text3.setText(“没有该单词”);
}
}
}
}
public class Example7_3
{ public static void main(String args[])
{ MyWindow win=new MyWindow();
}
}
例子4
import java.awt.;
import java.awt.event.;
class YourWindow extends Frame implements ActionListener
{ TextField text1,text2;
PoliceMan police;
YourWindow()
{ text1=new TextField(10);
text2=new TextField(10);
police=new PoliceMan();
setLayout(new FlowLayout());
add(text1);
add(text2);
text1.addActionListener(this);
text1.addActionListener(police);
setBounds(100,100,150,150);
setVisible(true);
validate();
}
public void actionPerformed(ActionEvent e)
{ String number=e.getActionCommand();
int n=Integer.parseInt(number);
int m=nn;
text2.setText(n+“的平方是:”+m);
}
}
class PoliceMan implements ActionListener
{ public void actionPerformed(ActionEvent e)
{ String number=e.getActionCommand();
int n=Integer.parseInt(number);
int m=nnn;
System.out.println(n+“的立方是:”+m);
}
}
public class Example7_4
{ public static void main(String args[])
{ YourWindow win=new YourWindow();
}
}
例子5
import java.awt.;
import java.awt.event.;
public class Example7_5
{ public static void main(String args[])
{ HisWindow win=new HisWindow();
}
}
class HisWindow extends Frame
{ TextField text1,text2,text3;
HisWindow()
{ text1=new TextField(10);
text2=new TextField(10);
text3=new TextField(10);
setLayout(new FlowLayout());
add(text1);
add(text2);
add(text3);
PoliceMan police=new PoliceMan();
text1.addActionListener(police);//内部类的实例做监视器
text1.addActionListener(new ActionListener()
{ //和接口有关的匿名类的实例做监视器
public void actionPerformed(ActionEvent e)
{ String number=e.getActionCommand();
int n=Integer.parseInt(number);
int m=nn;
text2.setText(n+“的平方是:”+m);
}
}
);
setBounds(100,100,150,150);
setVisible(true);
validate();
}
class PoliceMan implements ActionListener //内部类
{ public void actionPerformed(ActionEvent e)
{ String number=e.getActionCommand();
int n=Integer.parseInt(number);
int m=nnn;
text3.setText(n+“的立方是:”+m);
}
}
}
例子6
import java.awt.;
import java.awt.event.;
class WindowButton extends Frame
implements ActionListener
{ int number;
Label 提示条;
TextField 输入框;
Button buttonGetNumber,buttonEnter;
WindowButton(String s)
{ super(s);
setLayout(new FlowLayout());
buttonGetNumber=new Button(“得到一个随机数”);
add(buttonGetNumber);
提示条=new Label(“输入你的猜测：”,Label.CENTER);
提示条.setBackground(Color.cyan);
输入框=new TextField(“0”,10);
add(提示条);
add(输入框);
buttonEnter=new Button(“确定”);
add(buttonEnter);
buttonEnter.addActionListener(this);
buttonGetNumber.addActionListener(this);
setBounds(100,100,150,150);
setVisible(true);
validate();
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()==buttonGetNumber)
{ number=(int)(Math.random()100)+1;
提示条.setText(“输入你的猜测：”);
}
else if(e.getSource()buttonEnter)
{ int guess=0;
try { guess=Integer.parseInt(输入框.getText());
if(guessnumber)
{ 提示条.setText(“猜对了！”);
}
else if(guess>number)
{ 提示条.setText(“猜大了！”);
输入框.setText(null);
}
else if(guess<number)
{ 提示条.setText(“猜小了！”);
输入框.setText(null);
}
}
catch(NumberFormatException event)
{ 提示条.setText(“请输入数字字符”);
}
}
}
}
public class Example7_6
{ public static void main(String args[])
{ WindowButton win=new WindowButton(“窗口”);
}
}
例子7
import java.awt.;
import java.awt.event.;
class MyButton extends Button
implements ActionListener
{ String name;
TextField text;
Container con;
MyButton(String s,Container con)
{ super(s);
this.con=con;
text=new TextField(8);
text.addActionListener(this);
this.addActionListener(this);
con.add(text);
con.add(this);
}
public void actionPerformed(ActionEvent e)
{ name=text.getText();
this.setLabel(name);
con.validate();
}
}
class WindowOk extends Frame
{ MyButton button;
WindowOk()
{ setLayout(new FlowLayout());
button=new MyButton(“确定”,this);
setBounds(100,100,150,150);
setVisible(true);
validate();
}
}
public class Example7_7
{ public static void main(String args[])
{ WindowOk win=new WindowOk();
}
}

例子8
import java.awt.;
import java.awt.event.;
class WindowExit extends Frame
implements ActionListener
{ MenuBar menubar;
Menu menu;
MenuItem itemExit;
WindowExit()
{ menubar=new MenuBar();
menu=new Menu(“文件”);
itemExit=new MenuItem(“退出”);
itemExit.setShortcut(new MenuShortcut(KeyEvent.VK_E));
menu.add(itemExit);
menubar.add(menu);
setMenuBar(menubar);
itemExit.addActionListener(this);
setBounds(100,100,150,150);
setVisible(true);
validate();
}
public void actionPerformed(ActionEvent e)
{ System.exit(0);
}
}
public class Example7_8
{ public static void main(String args[])
{ WindowExit win=new WindowExit();
}
}
例子9
import java.awt.;
import java.awt.event.;
import java.util.;
class WindowTextArea extends Frame implements TextListener,ActionListener
{ TextArea text1,text2;
Button buttonClear;
WindowTextArea()
{ setLayout(new FlowLayout());
text1=new TextArea(6,15);
text2=new TextArea(6,15);
buttonClear=new Button(“清空”);
add(text1);
add(text2);
add(buttonClear);
text2.setEditable(false);
text1.addTextListener(this);
buttonClear.addActionListener(this);
setBounds(100,100,350,160);
setVisible(true);
validate();
}
public void textValueChanged(TextEvent e)
{ String s=text1.getText();
StringTokenizer fenxi=new StringTokenizer(s," ,’\n’");
int n=fenxi.countTokens();
String a[]=new String[n];
for(int i=0;i<=n-1;i++)
{ String temp=fenxi.nextToken();
a[i]=temp;
}
Arrays.sort(a);
text2.setText(null);
for(int i=0;i<n;i++)
{ text2.append(a[i]+"\n");
}
}
public void actionPerformed(ActionEvent e)
{ text1.setText(null);
}
}
public class Example7_9
{ public static void main(String args[])
{ WindowTextArea win=new WindowTextArea();
}
}
例子10
import java.awt.;
import java.awt.event.;
class Mypanel extends Panel
implements ActionListener
{ Button button1,button2;
Color backColor;
Mypanel()
{ button1=new Button(“确定”);
button2=new Button(“取消”);
add(button1);
add(button2);
setBackground(Color.pink);
backColor=getBackground();
button1.addActionListener(this);
button2.addActionListener(this);
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()==button1)
{ setBackground(Color.cyan);
}
else if(e.getSource()==button2)
{ setBackground(backColor);
}
}
}
class WindowPanel extends Frame implements ActionListener
{ Mypanel panel1,panel2;
Button button;
WindowPanel()
{ setLayout(new FlowLayout());
panel1=new Mypanel();
panel2=new Mypanel();
button=new Button(“退出”);
add(panel1);
add(panel2);
add(button);
button.addActionListener(this);
setBounds(60,60,200,200);
setVisible(true);
validate();
}
public void actionPerformed(ActionEvent e)
{ System.exit(0);
}
}
public class Example7_10
{ public static void main(String args[])
{ new WindowPanel();
}
}
例子11
import java.awt.;
import java.awt.event.*;
class WindoTen extends Frame
implements ActionListener
{ Panel p;
ScrollPane scrollpane;
WindoTen()
{ setLayout(new FlowLayout());
p=new Panel();
scrollpane=new ScrollPane(ScrollPane.SCROLLBARS_ALWAYS);
p.add(new Button(“one”));
p.add(new Button(“two”));
p.add(new Button(“three”));
p.add(new Button(“four”));
scrollpane.add§;
add(scrollpane);
setBounds(60,60,200,200);
setVisible(true);
validate();
}
public void actionPerformed(ActionEvent e)
{ System.exit(0);
}
}
public class Example7_11
{ public static void main(String args[])
{ new WindoTen();
}
}

例子12
import java.awt.;
class WindowFlow extends Frame
{ WindowFlow(String s)
{ super(s);
FlowLayout flow=new FlowLayout();
flow.setAlignment(FlowLayout.LEFT);
flow.setHgap(2);
flow.setVgap(8);
setLayout(flow);
for(int i=1;i<=10;i++)
{ Button b=new Button("i am "+i);
add(b);
}
setBounds(100,100,150,120);
setVisible(true);
}
}
public class Example7_12
{ public static void main(String args[])
{ WindowFlow win=new WindowFlow(“FlowLayout布局窗口”);
}
}
例子13
import java.awt.;
class Example7_13
{ public static void main(String args[])
{ Frame win=new Frame(“窗体”);
win.setBounds(100,100,300,300);
win.setVisible(true);
Button bSouth=new Button(“我在南边”),
bNorth=new Button(“我在北边”),
bEast =new Button(“我在东边”),
bWest =new Button(“我在西边”);
TextArea bCenter=new TextArea(“我在中心”);
win.add(bNorth,BorderLayout.NORTH);
win.add(bSouth,BorderLayout.SOUTH);
win.add(bEast,BorderLayout.EAST);
win.add(bWest,BorderLayout.WEST);
win.add(bCenter,BorderLayout.CENTER);
win.validate();
}
}
例子14
import java.awt.;
import java.awt.event.;
class WinCard extends Frame implements ActionListener
{ CardLayout mycard;
Button buttonFirst,buttonLast,buttonNext;
Panel pCenter;
WinCard()
{ mycard=new CardLayout();
pCenter=new Panel();
pCenter.setLayout(mycard);
buttonFirst=new Button(“first”);
buttonLast=new Button(“last”);
buttonNext=new Button(“next”);
for(int i=1;i<=20;i++)
{ pCenter.add(“i am”+i,new Button(“我是第 “+i+” 个按钮”));
}
buttonFirst.addActionListener(this);
buttonLast.addActionListener(this);
buttonNext.addActionListener(this);
Panel pSouth=new Panel();
pSouth.add(buttonFirst);
pSouth.add(buttonNext);
pSouth.add(buttonLast);
add(pCenter,BorderLayout.CENTER);
add(pSouth,BorderLayout.SOUTH);
setBounds(10,10,200,190);
setVisible(true);
validate();
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()==buttonFirst)
{ mycard.first(pCenter);
}
else if(e.getSource()==buttonNext)
{ mycard.next(pCenter);
}
else if(e.getSource()==buttonLast)
{ mycard.last(pCenter);
}
}
}
public class Example7_14
{ public static void main(String args[])
{ new WinCard();
}
}

例子15
import java.awt.;
import java.awt.event.;
class WinGrid extends Frame
{ GridLayout grid;
WinGrid()
{ grid=new GridLayout(12,12);
setLayout(grid);
Label label[][]=new Label[12][12];
for(int i=0;i<12;i++)
{ for(int j=0;j<12;j++)
{ label[i][j]=new Label();
if((i+j)%20)
label[i][j].setBackground(Color.black);
else
label[i][j].setBackground(Color.white);
add(label[i][j]);
}
}
setBounds(10,10,260,260);
setVisible(true);
validate();
}
}
public class Example7_15
{ public static void main(String args[])
{ new WinGrid();
}
}
例子16
import javax.swing.;
import java.awt.;
import javax.swing.border.;
public class Example7_16
{ public static void main(String args[])
{ new WindowBox();
}
}
class WindowBox extends Frame
{ Box baseBox ,boxV1,boxV2;
WindowBox()
{ boxV1=Box.createVerticalBox();
boxV1.add(new Label(“姓名”));
boxV1.add(Box.createVerticalStrut(8));
boxV1.add(new Label(“email”));
boxV1.add(Box.createVerticalStrut(8));
boxV1.add(new Label(“职业”));
boxV2=Box.createVerticalBox();
boxV2.add(new TextField(12));
boxV2.add(Box.createVerticalStrut(8));
boxV2.add(new TextField(12));
boxV2.add(Box.createVerticalStrut(8));
boxV2.add(new TextField(12));
baseBox=Box.createHorizontalBox();
baseBox.add(boxV1);
baseBox.add(Box.createHorizontalStrut(10));
baseBox.add(boxV2);
setLayout(new FlowLayout());
add(baseBox);
setBounds(120,125,250,150);
setVisible(true);
}
}
例子17
import java.awt.;
import java.awt.event.*;
class WindowNull extends Frame
{ WindowNull()
{ setLayout(null);
MyButton button=new MyButton();
Panel p=new Panel();
p.setLayout(null);
p.setBackground(Color.cyan);
p.add(button);
button.setBounds(20,10,25,70);
add§;
p.setBounds(50,50,90,100);
setBounds(120,125,200,200);
setVisible(true);
}
}
class MyButton extends Button implements ActionListener
{ int n=-1;
MyButton()
{ addActionListener(this);
}
public void paint(Graphics g)
{ g.drawString(“单”,6,16);
g.drawString(“击”,6,36);
g.drawString(“我”,6,56);
}
public void actionPerformed(ActionEvent e)
{ n=(n+1)%3;
if(n0)
setBackground(Color.red);
else if(n1)
setBackground(Color.yellow);
else if(n2)
setBackground(Color.green);
}
}
public class E
{ public static void main(String args[])
{ new WindowNull();
}
}
例子18
import java.awt.;
import java.awt.event.;
class Mycanvas extends Canvas
{ int x,y,r;
Mycanvas()
{ setBackground(Color.cyan);
}
public void setX(int x)
{ this.x=x;
}
public void setY(int y)
{ this.y=y;
}
public void setR(int r)
{ this.r=r;
}
public void paint(Graphics g)
{ g.drawOval(x,y,2r,2r);
}
}
class WindowCanvas extends Frame implements ActionListener
{ Mycanvas canvas;
TextField inputR,inputX,inputY;
Button b;
WindowCanvas()
{ canvas=new Mycanvas();
inputR=new TextField(5);
inputX=new TextField(4);
inputY=new TextField(4);
Panel pNorth=new Panel(),
pSouth=new Panel();
pNorth.add(new Label(“圆的位置坐标：”));
pNorth.add(inputX);
pNorth.add(inputY);
pSouth.add(new Label(“圆的半径：”));
pSouth.add(inputR);
b=new Button(“确定”);
b.addActionListener(this);
pSouth.add(b);
add(canvas,BorderLayout.CENTER);
add(pNorth,BorderLayout.NORTH);
add(pSouth,BorderLayout.SOUTH);
setBounds(100,100,300,200);
setVisible(true);
}
public void actionPerformed(ActionEvent e)
{ int x,y,r;
try { x=Integer.parseInt(inputX.getText());
y=Integer.parseInt(inputY.getText());
r=Integer.parseInt(inputR.getText());
canvas.setX(x);
canvas.setY(y);
canvas.setR®;
canvas.repaint();
}
catch(NumberFormatException ee)
{ x=0;y=0;r=0;
}
}
}
public class Example7_18
{ public static void main(String args[])
{ new WindowCanvas();
}
}
例子19
import java.awt.;
import java.awt.event.;
class Mypanel1 extends Panel implements ItemListener
{ Checkbox box1,box2,box3;
CheckboxGroup sex;
TextArea text;
Mypanel1(TextArea text)
{ this.text=text;
sex=new CheckboxGroup();
box1=new Checkbox(“男”,true,sex);
box2=new Checkbox(“女”,false,sex);
box1.addItemListener(this);
box2.addItemListener(this);
add(box1);
add(box2);
}
public void itemStateChanged(ItemEvent e)
{ Checkbox box=(Checkbox)e.getSource();
if(box.getState())
{ int n=text.getCaretPosition();
text.insert(box.getLabel(),n);
}
}
}
class Mypanel2 extends Panel implements ItemListener
{ Checkbox box1,box2,box3;
TextArea text;
Mypanel2(TextArea text)
{ this.text=text;
box1=new Checkbox(“张三”);
box2=new Checkbox(“李四”);
box1.addItemListener(this);
box2.addItemListener(this);
add(box1);
add(box2);
}
public void itemStateChanged(ItemEvent e)
{ Checkbox box=(Checkbox)e.getItemSelectable();
if(box.getState())
{ int n=text.getCaretPosition();
text.insert(box.getLabel(),n);
}
}
}
class WindowBox extends Frame
{ Mypanel1 panel1;
Mypanel2 panel2;
TextArea text;
WindowBox()
{ text=new TextArea();
panel1=new Mypanel1(text);
panel2=new Mypanel2(text);
add(panel1,BorderLayout.SOUTH);
add(panel2,BorderLayout.NORTH);
add(text,BorderLayout.CENTER);
setSize(200,200);
setVisible(true);
validate();
}
}
public class Example7_19
{ public static void main(String args[])
{ new WindowBox();
}
}
例子20
import java.awt.;
import java.awt.event.;
class WindowChoice extends Frame
implements ItemListener,ActionListener
{ Choice choice;
TextField text;
TextArea area;
Button add,del;
WindowChoice()
{ setLayout(new FlowLayout());
choice=new Choice();
text=new TextField(8);
area=new TextArea(6,25);
choice.add(“音乐天地”);
choice.add(“武术天地”);
choice.add(“象棋乐园”);
choice.add(“交友聊天”);
add=new Button(“添加”);
del=new Button(“删除”);
add.addActionListener(this);
text.addActionListener(this);
del.addActionListener(this);
choice.addItemListener(this);
add(choice);
add(del);
add(text);
add(add);
add(area);
setSize(200,200);
setVisible(true);
validate();
}
public void itemStateChanged(ItemEvent e)
{ String name=choice.getSelectedItem();
int index=choice.getSelectedIndex();
area.setText("\n"+index+":"+name);
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()==add||e.getSource()text)
{ String name=text.getText();
if(name.length()>0)
{ choice.add(name);
choice.select(name);
area.append("\n列表添加："+name);
}
}
else if(e.getSource()del)
{ area.append("\n列表删除："+choice.getSelectedItem());
choice.remove(choice.getSelectedIndex());
}
}
}
public class Example7_20
{ public static void main(String args[])
{ new WindowChoice();
}
}
例子21
import java.awt.;
import java.awt.event.;
class WindowList extends Frame
implements ItemListener,ActionListener
{ List list1,list2;
TextArea text1,text2;
int index=0;
WindowList()
{ setLayout(new FlowLayout());
list1=new List(3,false);
list2=new List(3,false);
text1=new TextArea(2,20);
text2=new TextArea(2,20);
list1.add(“计算1+2+…”);
list1.add(“计算11+22+…”);
list1.add(“计算111+222+…”);
for(int i=1;i<=100;i++)
{ list2.add(“前”+i+“项和”);
}
add(list1);
add(list2);
add(text1);
add(text2);
list1.addItemListener(this);
list2.addActionListener(this);
setSize(400,200);
setVisible(true);
validate();
}
public void itemStateChanged(ItemEvent e)
{ if(e.getItemSelectable()list1)
{ text1.setText(list1.getSelectedItem());
index=list1.getSelectedIndex();
}
}
public void actionPerformed(ActionEvent e)
{ int n=list2.getSelectedIndex(),sum=0;
String name=list2.getSelectedItem();
switch(index)
{ case 0:
for(int i=1;i<=n+1;i++)
{ sum=sum+i;
}
break;
case 1:
for(int i=1;i<=n+1;i++)
{ sum=sum+ii;
}
break;
case 2:
for(int i=1;i<=n+1;i++)
{ sum=sum+iii;
}
break;
default :
sum=-100;
}
text2.setText(name+“等于”+sum);
}
}
public class Example7_21
{ public static void main(String args[])
{ new WindowList();
}
}
例子22
import java.awt.;
import java.awt.event.;
import javax.swing.JTextArea;
class Win extends Frame
implements ItemListener
{ Choice list;
JTextArea text;
Win()
{ list=new Choice();
text=new JTextArea();
text.setForeground(Color.blue);
GraphicsEnvironment ge=
GraphicsEnvironment.getLocalGraphicsEnvironment();
String fontName[]=ge.getAvailableFontFamilyNames();
for(int i=0;i<fontName.length;i++)
{ list.add(fontName[i]);
}
add(list,BorderLayout.NORTH);
add(text,BorderLayout.CENTER);
text.setForeground(Color.green);
list.addItemListener(this);
setVisible(true);
setBounds(100,120,300,300);
validate();
}
public void itemStateChanged(ItemEvent e)
{ String name=list.getSelectedItem();
Font f=new Font(name,Font.BOLD,32);
text.setFont(f);
text.setText("\nWelcome 欢迎");
}
}
public class Example7_22
{ public static void main(String args[])
{ Win win=new Win();
}
}
例子23
import java.awt.;
import java.awt.event.;
class MyWin extends Frame
implements ActionListener
{ Button button;
Label label;
MyWin()
{
setLayout(null);
Cursor c=Cursor.getPredefinedCursor(Cursor.HAND_CURSOR);
setCursor©;
button=new Button(“横向走动”);
button.setBackground(Color.pink);
button.addActionListener(this);
label=new Label(“我可以被碰掉”,Label.CENTER);
label.setBackground(Color.yellow);
button.setCursor(Cursor.getPredefinedCursor(Cursor.MOVE_CURSOR));
add(button);
add(label);
button.setBounds(20,80,80,20);
label.setBounds(150,80,80,20);
setVisible(true);
setBounds(100,120,300,300);
validate();
}
public void actionPerformed(ActionEvent e)
{ Rectangle rect=button.getBounds();
int x=(int)rect.getX();
int y=(int)rect.getY();
if(rect.intersects(label.getBounds()))
{ label.setVisible(false);
}
if(label.isVisible())
{ x=x+2;
button.setLocation(x,y);
}
else
{ y=y+3;
button.setLocation(x,y);
button.setLabel(“纵向走动”);
}
}
}
public class Example7_23
{ public static void main(String args[])
{ MyWin win=new MyWin();
}
}
例子24
import java.awt.;
import java.awt.event.;
class MyButton extends Button
implements ActionListener
{ int x=10,y=10,i=0;
Color color[]={Color.red,Color.yellow,Color.green};
Color c=color[0];
MyButton()
{ setSize(38,85);
setBackground(Color.cyan);
addActionListener(this);
}
public void paint(Graphics g)
{ g.setColor©;
g.fillOval(x,y,20,20);
}
public void update(Graphics g)
{ g.clearRect(x,y,20,20);
paint(g);
}
public void actionPerformed(ActionEvent e)
{ i=(i+1)%3;
c=color[i];
y=y+23;
if(y>56)
y=10;
repaint();
}
}
class WindowCanvas extends Frame
{ WindowCanvas()
{ MyButton button=new MyButton();
setLayout(null);
add(button);
button.setLocation(30,30);
setBounds(60,125,100,200);
setVisible(true);
validate();
}
}
public class Example7_24
{ public static void main(String args[])
{ new WindowCanvas();
}
}
例子25
import java.awt.;
import java.awt.event.;
class MyFrame extends Frame
implements WindowListener
{ TextArea text;
MyFrame()
{ setBounds(100,100,200,300);
setVisible(true);
text=new TextArea();
add(text,BorderLayout.CENTER);
addWindowListener(this);
validate();
}
public void windowActivated(WindowEvent e)
{ text.append("\n我被激活");
validate();
}
public void windowDeactivated(WindowEvent e)
{ text.append("\n我不是激活状态了");
setBounds(0,0,400,400);
validate();
}
public void windowClosing(WindowEvent e)
{ text.append("\n窗口正在关闭呢");
dispose();
}
public void windowClosed(WindowEvent e)
{ System.out.println(“程序结束运行”);
System.exit(0);
}
public void windowIconified(WindowEvent e)
{ text.append("\n我图标化了");
}
public void windowDeiconified(WindowEvent e)
{ text.append("\n我撤消图标化");
setBounds(0,0,400,400);
validate();
}
public void windowOpened(WindowEvent e){}
}
public class Example7_25
{ public static void main(String args[])
{ new MyFrame();
}
}
例子26
import java.awt.;
import java.awt.event.;
class MyFrame extends Frame
{ TextArea text;
Boy police;
MyFrame(String s)
{ super(s);
police=new Boy(this);
setBounds(100,100,200,300);
setVisible(true);
text=new TextArea();
add(text,BorderLayout.CENTER);
addWindowListener(police);
validate();
}
}
class Boy extends WindowAdapter
{ MyFrame f;
public Boy(MyFrame f)
{ this.f=f;
}
public void windowActivated(WindowEvent e)
{ f.text.append("\n我被激活");
}
public void windowClosing(WindowEvent e)
{ System.exit(0);
}
}
public class Example7_26
{ public static void main(String args[])
{ new MyFrame(“窗口”);
}
}
例子27
import java.awt.;
mport java.awt.event.;
class MyFrame extends Frame
{ TextArea text;
MyFrame(String s)
{ super(s);
setBounds(100,100,200,300);
setVisible(true);
text=new TextArea(); add(text,BorderLayout.CENTER);
addWindowListener(new WindowAdapter()
{ public void windowActivated(WindowEvent e)
{ text.append("\n我被激活");
}
public void windowClosing(WindowEvent e)
{ System.exit(0);
}
}
);
validate();
}
}
public class Example7_27
{ public static void main(String args[])
{ new MyFrame(“窗口”);
}
}
例子28
import java.awt.;
import java.awt.event.;
class WindowMouse extends Frame
implements MouseListener
{ TextField text;
Button button;
TextArea textArea;
WindowMouse()
{ setLayout(new FlowLayout());
text=new TextField(10);
text.addMouseListener(this);
button=new Button(“按钮”);
button.addMouseListener(this);
addMouseListener(this);
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ System.exit(0);
}
}
);
textArea=new TextArea(5,28);
add(button);
add(text);
add(textArea);
setBounds(100,100,220,120);
setVisible(true);
}
public void mousePressed(MouseEvent e)
{ textArea.append("\n鼠标按下,位置:"+"("+e.getX()+","+e.getY()+")");
}
public void mouseReleased(MouseEvent e) {}
public void mouseEntered(MouseEvent e) {}
public void mouseExited(MouseEvent e) {}
public void mouseClicked(MouseEvent e)
{ if(e.getClickCount()>=2)
textArea.setText(“鼠标连击，位置:”+"("+e.getX()+","+e.getY()+")");
}
}
public class Example7_28
{ public static void main(String args[])
{ new WindowMouse();
}
}
例子29
import java.awt.;
import java.awt.event.*;
class MyCanvas extends Canvas
implements MouseListener
{ int left=-1,right=-1;
int x=-1,y=-1;
MyCanvas()
{ setBackground(Color.cyan) ;
addMouseListener(this);
}
public void paint(Graphics g)
{ if(left1)
{ g.drawOval(x-10,y-10,20,20);
}
else if(right1)
{ g.drawRect(x-8,y-8,16,16);
}
}
public void mousePressed(MouseEvent e)
{ x=e.getX();
y=e.getY();
if(e.getModifiers()InputEvent.BUTTON1_MASK)
{ left=1;
right=-1;
repaint();
}
else if(e.getModifiers()InputEvent.BUTTON3_MASK)
{ right=1;
left=-1;
repaint();
}
}
public void mouseReleased(MouseEvent e){}
public void mouseEntered(MouseEvent e){}
public void mouseExited(MouseEvent e)
{ left=-1;
right=-1;
repaint();
}
public void mouseClicked(MouseEvent e){}
public void update(Graphics g)
{ if(left1||right1)
{ paint(g);
}
else
{ super.update(g);
}
}
}
public class Example7_29
{ public static void main(String args[])
{ Frame f=new Frame();
f.setBounds(100,100,200,200);f.setVisible(true);
f.addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ System.exit(0);
}
});
f.add(new MyCanvas(),BorderLayout.CENTER);
f.validate();
}
}
例子30
import java.awt.;
import java.awt.event.;
import javax.swing.SwingUtilities;
class Win extends Frame implements MouseListener,MouseMotionListener
{ Button button;
TextField text;
int x,y;
boolean move=false;
Win()
{ button=new Button(“用鼠标拖动我”);
text=new TextField(“用鼠标拖动我”,8);
button.addMouseListener(this);
button.addMouseMotionListener(this);
text.addMouseListener(this);
text.addMouseMotionListener(this);
addMouseMotionListener(this);
setLayout(new FlowLayout());
add(button);
add(text);
addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
System.exit(0);
}
});
setBounds(10,10,350,300);
setVisible(true);
validate();
}
public void mousePressed(MouseEvent e) {}
public void mouseReleased(MouseEvent e)
{
move=false;
}
public void mouseEntered(MouseEvent e) {}
public void mouseExited(MouseEvent e) {}
public void mouseClicked(MouseEvent e){}
public void mouseMoved(MouseEvent e){}
public void mouseDragged(MouseEvent e)
{ Component com=null;
if(e.getSource() instanceof Component)
{ com=(Component)e.getSource();
if(com!=this)
move=true;
e=SwingUtilities.convertMouseEvent(com,e,this);
if(move)
{ x=e.getX();
y=e.getY();
int w=com.getSize().width,
h=com.getSize().height;
com.setLocation(x-w/2,y-h/2);
}
}
}
}
public class Example7_30
{ public static void main(String args[])
{ Win win=new Win();
}
}
例子31
import java.awt.;
import java.awt.event.;
class Win extends Frame implements MouseListener,MouseMotionListener
{ Button button;
TextField text;
int x,y,a,b,x0,y0;
Win()
{ button=new Button(“用鼠标拖动我”);
text=new TextField(“用鼠标拖动我”,8);
button.addMouseListener(this);
button.addMouseMotionListener(this);
text.addMouseListener(this);
text.addMouseMotionListener(this);
setLayout(new FlowLayout());
add(text);
add(button);
addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
System.exit(0);
}
});
setBounds(10,10,350,300);
setVisible(true);
validate();
}
public void mousePressed(MouseEvent e)
{ Component com=null;
com=(Component)e.getSource();
a=com.getBounds().x;
b=com.getBounds().y;
x0=e.getX();
y0=e.getY();
}
public void mouseReleased(MouseEvent e){}
public void mouseEntered(MouseEvent e) {}
public void mouseExited(MouseEvent e) {}
public void mouseClicked(MouseEvent e){}
public void mouseMoved(MouseEvent e){}
public void mouseDragged(MouseEvent e)
{ Component com=null;
if(e.getSource() instanceof Component)
{ com=(Component)e.getSource();
a=com.getBounds().x;
b=com.getBounds().y;
x=e.getX();
y=e.getY();
a=a+x;
b=b+y;
com.setLocation(a-x0,b-y0);
}
}
}
public class Example7_31
{ public static void main(String args[])
{ Win win=new Win();
}
}
例子32
import java.awt.;
import java.awt.event.;
class MyWindow extends Frame implements FocusListener
{ TextField text;
Button button;
MyWindow(String s)
{ super(s);
text=new TextField(10);
button=new Button(“按钮”);
text.requestFocusInWindow();
setLayout(new FlowLayout());
add(text);
add(button);
text.addFocusListener(this);
button.addFocusListener(this);
setBounds(100,100,150,150);
setVisible(true);
validate();
}
public void focusGained(FocusEvent e)
{ Component com=(Component)e.getSource();
com.setBackground(Color.blue);
if(comtext)
text.setText(null);
}
public void focusLost(FocusEvent e)
{ Component com=(Component)e.getSource();
com.setBackground(Color.red);
}
}
public class Example7_32
{ public static void main(String args[])
{ MyWindow win=new MyWindow(“窗口”);
}
}
例子33
import java.awt.;
import java.awt.event.;
class Win extends Frame implements KeyListener
{ Button b[]=new Button[8];
int x,y;
Win()
{ setLayout(new FlowLayout());
for(int i=0;i<8;i++)
{ b[i]=new Button(""+i);
b[i].addKeyListener(this);
add(b[i]);
}
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e){
System.exit(0);
}
});
setBounds(10,10,300,300);
setVisible(true);
validate();
}
public void keyPressed(KeyEvent e)
{ Button button=(Button)e.getSource();
x=button.getBounds().x;
y=button.getBounds().y;
if(e.getKeyCode()==KeyEvent.VK_UP)
{ y=y-2;
if(y<=0) y=0;
button.setLocation(x,y);
}
else if(e.getKeyCode()==KeyEvent.VK_DOWN)
{ y=y+2;
if(y>=300) y=300;
button.setLocation(x,y);
}
else if(e.getKeyCode()==KeyEvent.VK_LEFT)
{ x=x-2;
if(x<=0) x=0;
button.setLocation(x,y);
}
else if(e.getKeyCode()KeyEvent.VK_RIGHT)
{ x=x+2;
if(x>=300) x=300;
button.setLocation(x,y);
}
}
public void keyTyped(KeyEvent e) {}
public void keyReleased(KeyEvent e) {}
}
public class Example7_33
{ public static void main(String args[])
{ Win win=new Win();
}
}
例子34
import java.awt.;
import java.awt.event.;
class Win extends Frame implements KeyListener
{ Button b;
Win()
{ setLayout(new FlowLayout());
b=new Button(“我是一个按钮,”);
b.addKeyListener(this);
add(b);
addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
System.exit(0);
}
});
setBounds(10,10,300,300);
setVisible(true);
validate();
}
public void keyPressed(KeyEvent e)
{ Button button=(Button)e.getSource();
int x=0,y=0,w=0,h=0;
x=button.getBounds().x;
y=button.getBounds().y;
w=button.getBounds().width;
h=button.getBounds().height;
if(e.getModifiers()InputEvent.SHIFT_MASK&&e.getKeyCode()KeyEvent.VK_X)
{ button.setLocation(y,x);
}
else if(e.getModifiers()InputEvent.CTRL_MASK&&e.getKeyCode()KeyEvent.VK_X)
{ button.setSize(h,w);
}
}
public void keyTyped(KeyEvent e) {}
public void keyReleased(KeyEvent e) {}
}
public class Example7_34
{ public static void main(String args[])
{ Win win=new Win();
}
}
例子35
import java.awt.;
import java.awt.event.;
class Win extends Frame
implements KeyListener, FocusListener
{ TextField text[]=new TextField[3];
Win()
{ addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
System.exit(0);
}
});
setLayout(new FlowLayout());
for(int i=0;i<3;i++)
{ text[i]=new TextField(7);
text[i].addKeyListener(this);
text[i].addFocusListener(this);
add(text[i]);
}
text[0].requestFocusInWindow();
setBounds(10,10,300,300);
setVisible(true);
validate();
}
public void keyPressed(KeyEvent e)
{ TextField text=(TextField)e.getSource();
if(text.getCaretPosition()>=6)
{ text.transferFocus();
}
}
public void keyTyped(KeyEvent e) {}
public void keyReleased(KeyEvent e) {}
public void focusGained(FocusEvent e)
{ TextField text=(TextField)e.getSource();
text.setText(null);
}
public void focusLost(FocusEvent e){}
}
public class Example7_35
{ public static void main(String args[])
{ Win win=new Win();
}
}
例子36
import java.awt.;
import java.awt.event.;
import java.awt.datatransfer.;
class Win extends Frame implements ActionListener
{ MenuBar menubar;
Menu menu;
MenuItem copy,cut,paste;
TextArea text1,text2;
Clipboard clipboard=null;
Win()
{ clipboard=getToolkit().getSystemClipboard();
menubar=new MenuBar();
menu=new Menu(“Edit”);
copy=new MenuItem(“copy”);
cut=new MenuItem (“cut”);
paste=new MenuItem (“paste”);
text1=new TextArea(10,20);
text2=new TextArea(10,20);
copy.addActionListener(this);
cut.addActionListener(this);
paste.addActionListener(this);
setLayout(new FlowLayout());
menubar.add(menu);
menu.add(copy);
menu.add(cut);
menu.add(paste);
setMenuBar(menubar);
add(text1);
add(text2);
setBounds(100,100,400,350);
setVisible(true);
validate();
addWindowListener(new WindowAdapter()
{public void windowClosing(WindowEvent e)
{System.exit(0);
}
});
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()==copy)
{ String temp=text1.getSelectedText();
StringSelection text=new StringSelection(temp);
clipboard.setContents(text,null);
}
else if(e.getSource()==cut)
{ String temp=text1.getSelectedText();
StringSelection text=new StringSelection(temp);
clipboard.setContents(text,null);
int start=text1.getSelectionStart();
int end =text1.getSelectionEnd();
text1.replaceRange("",start,end) ;
}
else if(e.getSource()==paste)
{ Transferable contents=clipboard.getContents(this);
DataFlavor flavor= DataFlavor.stringFlavor;
if( contents.isDataFlavorSupported(flavor))
try{ String str;
str=(String)contents.getTransferData(flavor);
text2.append(str);
}
catch(Exception ee){}
}
}
}
public class Example7_36
{ public static void main(String args[])
{ Win win=new Win ();
}
}
例子37
import java.awt.;import java.awt.event.;
public class Example7_37
{ public static void main(String args[])
{ MyFrame f=new MyFrame();
f.setBounds(70,70,70,89);f.setVisible(true);f.validate();
}
}
class MyFrame extends Frame implements ActionListener
{ PrintJob p=null; //声明一个PrintJob对象。
Graphics g=null;
TextArea text=new TextArea(10,10);
Button 打印文本框=new Button(“打印文本框”),
打印窗口=new Button(“打印窗口”),
打印按扭=new Button(“打印按扭”);
MyFrame()
{ super(“在应用程序中打印”);
打印文本框.addActionListener(this);
打印窗口.addActionListener(this);
打印按扭.addActionListener(this);
add(text,“Center”);
Panel panel=new Panel();
panel.add(打印文本框); panel.add(打印窗口); panel.add(打印按扭);
add(panel,“South”);
addWindowListener(new WindowAdapter()
{public void windowClosing(WindowEvent e)
{System.exit(0); }
});
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()==打印文本框)
{ p=getToolkit().getPrintJob(this,“ok”,null);
g=p.getGraphics();
g.translate(120,200);
text.printAll(g);
g.dispose();
p.end();
}
else if(e.getSource()==打印窗口)
{ p=getToolkit().getPrintJob(this,“ok”,null);
g=p.getGraphics();
g.translate(120,200);
this.printAll(g);
g.dispose();
p.end();
}
else if(e.getSource()==打印按扭)
{ p=getToolkit().getPrintJob(this,“ok”,null);
g=p.getGraphics();
g.translate(120,200);
打印文本框.printAll(g);
g.translate(78,0);
打印窗口.printAll(g);
g.translate(66,0);
打印按扭.printAll(g);
g.dispose();
p.end();
}
}
}
例子38
import java.awt.;
import java.awt.event.;
class ChessPad extends Panel implements MouseListener,ActionListener
{ int x=-1,y=-1, 棋子颜色=1;
Button button=new Button(“重新开局”);
TextField text_1=new TextField(“请黑棋下子”),
text_2=new TextField();
ChessPad()
{ setSize(440,440);
setLayout(null);setBackground(Color.orange);
addMouseListener(this);add(button);button.setBounds(10,5,60,26);
button.addActionListener(this);
add(text_1);text_1.setBounds(90,5,90,24);
add(text_2);text_2.setBounds(290,5,90,24);
text_1.setEditable(false);text_2.setEditable(false);
}
public void paint(Graphics g)
{ for(int i=40;i<=380;i=i+20)
{ g.drawLine(40,i,400,i);
}
g.drawLine(40,400,400,400);
for(int j=40;j<=380;j=j+20)
{ g.drawLine(j,40,j,400);
}
g.drawLine(400,40,400,400);
g.fillOval(97,97,6,6); g.fillOval(337,97,6,6);
g.fillOval(97,337,6,6);g.fillOval(337,337,6,6);
g.fillOval(217,217,6,6);
}
public void mousePressed(MouseEvent e)
{ if(e.getModifiers()InputEvent.BUTTON1_MASK)
{ x=(int)e.getX();y=(int)e.getY();
ChessPoint_black chesspoint_black=new ChessPoint_black(this);
ChessPoint_white chesspoint_white=new ChessPoint_white(this);
int a=(x+10)/20,b=(y+10)/20;
if(x/20<2||y/20<2||x/20>19||y/20>19)
{}
else
{
if(棋子颜色1)
{ this.add(chesspoint_black);
chesspoint_black.setBounds(a20-10,b20-10,20,20);
棋子颜色=棋子颜色(-1);
text_2.setText(“请白棋下子”);
text_1.setText("");
}
else if(棋子颜色-1)
{ this.add(chesspoint_white);
chesspoint_white.setBounds(a20-10,b20-10,20,20);
棋子颜色=棋子颜色*(-1);
text_1.setText(“请黑棋下子”);
text_2.setText("");
}
}
}
}
public void mouseReleased(MouseEvent e){}
public void mouseEntered(MouseEvent e) {}
public void mouseExited(MouseEvent e) {}
public void mouseClicked(MouseEvent e){}
public void actionPerformed(ActionEvent e)
{ this.removeAll();棋子颜色=1;
add(button);button.setBounds(10,5,60,26);
add(text_1);text_1.setBounds(90,5,90,24);
text_2.setText("");text_1.setText(“请黑棋下子”);
add(text_2);text_2.setBounds(290,5,90,24);
}
}
class ChessPoint_black extends Canvas implements MouseListener
{ ChessPad chesspad=null;
ChessPoint_black(ChessPad p)
{ setSize(20,20);chesspad=p; addMouseListener(this);
}
public void paint(Graphics g)
{ g.setColor(Color.black);g.fillOval(0,0,20,20);
}
public void mousePressed(MouseEvent e)
{ if(e.getModifiers()InputEvent.BUTTON3_MASK)
{ chesspad.remove(this);
chesspad.棋子颜色=1;
chesspad.text_2.setText("");chesspad.text_1.setText(“请黑棋下子”);
}
}
public void mouseReleased(MouseEvent e){}
public void mouseEntered(MouseEvent e) {}
public void mouseExited(MouseEvent e) {}
public void mouseClicked(MouseEvent e)
{ if(e.getClickCount()>=2)
chesspad.remove(this);
}
}
class ChessPoint_white extends Canvas implements MouseListener
{ ChessPad chesspad=null;
ChessPoint_white(ChessPad p)
{ setSize(20,20);addMouseListener(this);
chesspad=p;
}
public void paint(Graphics g)
{ g.setColor(Color.white);g.fillOval(0,0,20,20);
}
public void mousePressed(MouseEvent e)
{ if(e.getModifiers()InputEvent.BUTTON3_MASK)
{ chesspad.remove(this);chesspad.棋子颜色=-1;
chesspad.text_2.setText(“请白棋下子”); chesspad.text_1.setText("");
}
}
public void mouseReleased(MouseEvent e){}
public void mouseEntered(MouseEvent e) {}
public void mouseExited(MouseEvent e) {}
public void mouseClicked(MouseEvent e)
{ if(e.getClickCount()>=2)
chesspad.remove(this);
}
}
public class Chess extends Frame
{ ChessPad chesspad=new ChessPad();
Chess()
{ setVisible(true);
setLayout(null);
Label label=
new Label(“单击左键下棋子，双击吃棋子，用右键单击棋子悔棋”,Label.CENTER);
add(label);label.setBounds(70,55,440,26);
label.setBackground(Color.orange);
add(chesspad);chesspad.setBounds(70,90,440,440);
addWindowListener(new WindowAdapter()
{public void windowClosing(WindowEvent e)
{System.exit(0);
}
});
pack();setSize(600,550);
}
public static void main(String args[])
{ Chess chess=new Chess();
}
}
例子39
import java.awt.;
import java.awt.event.;
public class MoveExample
{ public static void main(String args[])
{ new Hua_Rong_Road();
}
}
class Person extends Button
implements FocusListener
{ int number;
Color c=new Color(255,245,170);
Person(int number,String s)
{ super(s);
setBackground©;
this.number=number;
c=getBackground();
addFocusListener(this);
}
public void focusGained(FocusEvent e)
{ setBackground(Color.red);
}
public void focusLost(FocusEvent e)
{ setBackground©;
}
}
class Hua_Rong_Road extends Frame implements MouseListener,KeyListener,ActionListener
{ Person person[]=new Person[10];
Button left,right,above,below;
Button restart=new Button(“重新开始”);
public Hua_Rong_Road()
{ init();
setBounds(100,100,320,360);
setVisible(true);
validate();
addWindowListener( new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ System.exit(0);
}
}
);
}
public void init()
{ setLayout(null);
add(restart);
restart.setBounds(100,320,120,25);
restart.addActionListener(this);
String name[]={“曹操”,“关羽”,“张飞”,“刘备”,“周瑜”,“黄忠”,“兵”,“兵”,“兵”,“兵”};
for(int k=0;k<name.length;k++)
{ person[k]=new Person(k,name[k]);
person[k].addMouseListener(this);
person[k].addKeyListener(this);
add(person[k]);
}
person[0].setBounds(104,54,100,100);
person[1].setBounds(104,154,100,50);
person[2].setBounds(54, 154,50,100);
person[3].setBounds(204,154,50,100);
person[4].setBounds(54, 54, 50,100);
person[5].setBounds(204, 54, 50,100);
person[6].setBounds(54,254,50,50);
person[7].setBounds(204,254,50,50);
person[8].setBounds(104,204,50,50);
person[9].setBounds(154,204,50,50);
person[9].requestFocus();
left=new Button(); right=new Button();
above=new Button(); below=new Button();
add(left); add(right);
add(above); add(below);
left.setBounds(49,49,5,260);
right.setBounds(254,49,5,260);
above.setBounds(49,49,210,5);
below.setBounds(49,304,210,5);
validate();
}
public void keyTyped(KeyEvent e){}
public void keyReleased(KeyEvent e){}
public void keyPressed(KeyEvent e)
{ Person man=(Person)e.getSource();
if(e.getKeyCode()KeyEvent.VK_DOWN)
{ go(man,below);
}
if(e.getKeyCode()KeyEvent.VK_UP)
{ go(man,above);
}
if(e.getKeyCode()KeyEvent.VK_LEFT)
{ go(man,left);
}
if(e.getKeyCode()KeyEvent.VK_RIGHT)
{ go(man,right);
}
}
public void mousePressed(MouseEvent e)
{ Person man=(Person)e.getSource();
int x=-1,y=-1;
x=e.getX();
y=e.getY();
int w=man.getBounds().width;
int h=man.getBounds().height;
if(y>h/2)
{ go(man,below);
}
if(y<h/2)
{ go(man,above);
}
if(x<w/2)
{ go(man,left);
}
if(x>w/2)
{ go(man,right);
}
}
public void mouseReleased(MouseEvent e) {}
public void mouseEntered(MouseEvent e) {}
public void mouseExited(MouseEvent e) {}
public void mouseClicked(MouseEvent e) {}
public void go(Person man,Button direction)
{ boolean move=true;
Rectangle manRect=man.getBounds();
int x=man.getBounds().x;
int y=man.getBounds().y;
if(directionbelow)
y=y+50;
else if(directionabove)
y=y-50;
else if(directionleft)
x=x-50;
else if(directionright)
x=x+50;
manRect.setLocation(x,y);
Rectangle directionRect=direction.getBounds();
for(int k=0;k<10;k++)
{ Rectangle personRect=person[k].getBounds();
if((manRect.intersects(personRect))&&(man.number!=k))
{ move=false;
}
}
if(manRect.intersects(directionRect))
{ move=false;
}
if(movetrue)
{ man.setLocation(x,y);
}
}
public void actionPerformed(ActionEvent e)
{ dispose();
new Hua_Rong_Road();
}
}
例子40
Example7_40.java
import java.awt.;
import java.awt.event.;
class SelectWindow extends Frame implements ActionListener
{ PersonSelected personSelected[]; //存放候选人的数组
InputPerson input; //输入界面
SelectPane select; //选举界面
ResultArea show; //查看结果界面
Button buttonInput,buttonSelect,buttonResult,reNew;
int max=3; //每张选票上可推选的最多人数
CardLayout card;
Panel center=new Panel(),
south=new Panel();
SelectWindow()
{ personSelected=new PersonSelected[1]; //数组的初始大小是1
for(int k=0;k<personSelected.length;k++)
{ personSelected[k]=new PersonSelected(“无名”,0);
}
card=new CardLayout();
center.setLayout(card);
input=new InputPerson(personSelected);
select=new SelectPane(personSelected,max); //每张选票上最多推选max 人
show=new ResultArea(personSelected);
center.add(“001”,new Label(“选票程序”,Label.CENTER));
center.add(“input”,input);
center.add(“select”,select);
center.add(“show”,show);
buttonInput=new Button(“输入候选人界面”);
buttonInput.addActionListener(this);
buttonSelect=new Button(“统计选票界面,最多选”+max+“人”);
buttonSelect.addActionListener(this);
buttonResult=new Button(“查看得票界面”);
buttonResult.addActionListener(this);
reNew=new Button(“重新选举”);
reNew.addActionListener(this);
south.add(buttonInput);
south.add(buttonSelect);
south.add(buttonResult);
south.add(reNew);
add(center,BorderLayout.CENTER);
add(south,BorderLayout.SOUTH);
setSize(450,200);
setVisible(true);
validate();
}
public void actionPerformed(ActionEvent e)
{ Button b=(Button)e.getSource();
setTitle(b.getLabel());
if(bbuttonInput)
{ card.show(center,“input”); //切换到输入界面,以便修改personSelected数组
buttonInput.setEnabled(false);
}
if(bbuttonSelect)
{ personSelected=input.getPersonSelected(); //得到被输入界面修改后的数组
select.setPersonSelected(personSelected);
select.init();
card.show(center,“select”);
}
if(bbuttonResult)
{ personSelected=select.getPersonSelected(); //得到被选举界面修改后的数组
show.setPersonSelected(personSelected);
card.show(center,“show”);
}
if(breNew)
{ personSelected=new PersonSelected[1]; //数组的初始大小是1
for(int k=0;k<personSelected.length;k++)
{ personSelected[k]=new PersonSelected(“无名”,0);
}
center.removeAll();
input=new InputPerson(personSelected);
select=new SelectPane(personSelected,3); //每张选票上最多推选3人
show=new ResultArea(personSelected);
center.add(“001”,new Label(“选票程序”,Label.CENTER));
center.add(“input”,input);
center.add(“select”,select);
center.add(“show”,show);
card.show(center,“001”);
buttonInput.setEnabled(true);
center.validate();
}
}
}
public class Example7_40
{ public static void main(String args[])
{ SelectWindow win=new SelectWindow();
win.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e){
System.exit(0);
}
});
}
}
PersonSelected.java
import java.awt.;
public class PersonSelected extends Panel
{ String name; //候选人的名字
int count; //得票数
Checkbox box; //代表候选人外观的组件
public PersonSelected(String name,int count)
{ this.name=name;
this.count=count;
box=new Checkbox();
add(box);
}
public void setName(String name)
{ this.name=name;
box.setLabel(name);
}
public String getName()
{ return name;
}
public void addCount()
{ count++;
}
public int getCount()
{ return count;
}
public Checkbox getBox()
{ return box;
}
}
InputPerson.java
import java.awt.;
import java.awt.event.;
import java.util.StringTokenizer;
public class InputPerson extends Panel implements ActionListener
{ TextField inputPeopleName;
PersonSelected personSelected[]; //存放候选人的数组
Button button;
InputPerson(PersonSelected personSelected[])
{ this.personSelected=personSelected;
add(new Label(“输入侯选人名字,用逗号分隔”));
inputPeopleName=new TextField(16);
add(inputPeopleName);
button=new Button(“确定”);
add(button);
button.addActionListener(this);
}
public void actionPerformed(ActionEvent e)
{ String tempStr=inputPeopleName.getText();
if(tempStr.length()>0)
{ StringTokenizer token=new StringTokenizer(tempStr,",，");
personSelected=new PersonSelected[token.countTokens()];
int k=0;
while(token.hasMoreTokens())
{ String temp=token.nextToken();
personSelected[k]=new PersonSelected(temp,0);
personSelected[k].setName(temp);
k++;
}
}
else
{ inputPeopleName.setText(“请输入名字,并用逗号分隔”);
}
}
public PersonSelected [] getPersonSelected()
{ return personSelected;
}
}
SelectPane.java
import java.awt.;
import java.awt.event.*;
public class SelectPane extends Panel implements ActionListener,ItemListener
{ Label label=new Label(“请将你推选的人选中:”);
int maxSelectedNumber; //一张选票可推选的最多人数
int 弃权票数;
int totalVote;
PersonSelected personSelected[]; //存放候选人的数组
Button button;
SelectPane(PersonSelected personSelected[],int max)
{ this.personSelected=personSelected;
maxSelectedNumber=max;
button=new Button(“确认”);
button.addActionListener(this);
init();
}
public void init()
{ removeAll();
add(label);
for(int k=0;k<personSelected.length;k++)
{ personSelected[k].getBox().addItemListener(this);
add(personSelected[k].getBox());
}
add(button);
validate();
}
public void actionPerformed(ActionEvent e)
{ totalVote=totalVote+1; //记录下统计的票数
//检查选票上被推选的人数
int number=0;
for(int k=0;k<personSelected.length;k++)
{ if(personSelected[k].getBox().getState())
{ number++;
}
}
if(number0)
{ 弃权票数++;
}
else
{ for(int k=0;k<personSelected.length;k++)
{ if(personSelected[k].getBox().getState())
{ personSelected[k].addCount();
personSelected[k].getBox().setState(false);
}
}
}
label.setText(“已统计了:”+totalVote+“张选票,其中弃权票:”+弃权票数);
validate();
}
public void itemStateChanged(ItemEvent e)
{ Checkbox box=(Checkbox)e.getItemSelectable();
//检查选票是否符合规定的最多可推选的人数
int number=0;
for(int k=0;k<personSelected.length;k++)
{ if(personSelected[k].getBox().getState())
{ number++;
}
}
if(number>maxSelectedNumber)
{ box.setState(false); //不允许推选该人
}
}
public PersonSelected [] getPersonSelected()
{ return personSelected;
}
public void setPersonSelected(PersonSelected personSelected[])
{ this.personSelected=personSelected;
}
}
ResultArea.java
import java.awt.*;
public class ResultArea extends Panel
{ PersonSelected personSelected[]; //存放候选人的数组
TextArea text;
ResultArea( PersonSelected personSelected[])
{ this.personSelected=personSelected;
text=new TextArea(12,40);
text.setText(null);
add(text);
}
public void setPersonSelected(PersonSelected personSelected[])
{ text.setText(null);
String str[]=new String[personSelected.length];
int count[]=new int[personSelected.length];
for(int k=0;k<str.length;k++)
{ str[k]=personSelected[k].getName();
count[k]=personSelected[k].getCount();
}
for(int k=0;k<str.length;k++)
{ for(int i=k+1;i<str.length;i++)
if(count[i]>count[k])
{ String temp=str[k];
int n=count[k];
str[k]=str[i];
count[k]=count[i];
str[i]=temp;
count[i]=n;
}
}
for(int k=0;k<str.length;k++)
{ text.append("\n"+str[k]+“得票:”+count[k]);
}
validate();
}
}

第八章建立对话框
例子1
import java.awt.event.; import java.awt.;
class MyDialog extends Dialog implements ActionListener //建立对话框类
{ static final int YES=1,NO=0;
int message=-1; Button yes,no;
MyDialog(Frame f,String s,boolean b) //构造方法
{ super(f,s,b);
yes=new Button(“Yes”); yes.addActionListener(this);
no=new Button(“No”); no.addActionListener(this);
setLayout(new FlowLayout());
add(yes); add(no);
setBounds(60,60,100,100);
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ message=-1;setVisible(false);
}
}
);
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()==yes)
{ message=YES;setVisible(false);
}
else if(e.getSource()==no)
{ message=NO;setVisible(false);
}
}
public int getMessage()
{ return message;
}
}
class Dwindow extends Frame implements ActionListener
{ TextArea text; Button button; MyDialog dialog;
Dwindow(String s)
{ super(s);
text=new TextArea(5,22); button=new Button(“打开对话框”);
button.addActionListener(this);
setLayout(new FlowLayout());
add(button); add(text);
dialog=new MyDialog(this,“我有模式”,true);
setBounds(60,60,300,300); setVisible(true);
validate();
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ System.exit(0);
}
}
);
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()==button)
{ dialog.setVisible(true); //对话框激活状态时,堵塞下面的语句
//对话框消失后下面的语句继续执行：
if(dialog.getMessage()==MyDialog.YES) //如果单击了对话框的"yes"按钮
{ text.append("\n你单击了对话框的yes按钮");
}
else if(dialog.getMessage()==MyDialog.NO) //如果单击了对话框的"no"按钮
{ text.append("\n你单击了对话框的No按钮");
}
}
}
}
public class Example8_1
{ public static void main(String args[])
{ new Dwindow(“带对话框的窗口”);
}
}
例子2
import java.awt.;
import java.awt.event.;
class 圆 extends Dialog implements ActionListener//负责计算圆面积的对话框
{ double r,area;
TextField 半径=null,
结果=null;
Button b=null;
圆(Frame f,String s,boolean mode)
{
super(f,s,mode);
setLayout(new FlowLayout());
半径=new TextField(10);
结果=new TextField(10);
b=new Button(“确定”);
add(new Label(“输入半径”));
add(半径);
add(b);
add(new Label(“面积是:”));
add(结果);
validate();
b.addActionListener(this);
setBounds(60,60,260,100);
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ setVisible(false);
}
}
);
}
public void actionPerformed(ActionEvent e)
{ try
{ r=Double.parseDouble(半径.getText());
area=Math.PIrr;
结果.setText(""+area);
}
catch(Exception ee)
{ 半径.setText(“请输入数字字符”);
}
}
}
class 三角形 extends Dialog implements ActionListener//负责计算三角形面积的对话框
{ double a=0,b=0,c=0,area;
TextField 边_a=new TextField(6),
边_b=new TextField(6),
边_c=new TextField(6),
结果=new TextField(8);
Button button=new Button(“确定”);
三角形(Frame f,String s,boolean mode)
{ super(f,s,mode);
setLayout(new FlowLayout());
add(new Label(“输入三边的长度:”));
add(边_a); add(边_b); add(边_c);
add(button);
add(new Label(“面积是:”));
add(结果);
validate();
button.addActionListener(this);
setBounds(60,60,360,100);
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ setVisible(false);
}
}
);
}
public void actionPerformed(ActionEvent e)//获取三边的长度
{ try{ a=Double.parseDouble(边_a.getText());
b=Double.parseDouble(边_b.getText());
c=Double.parseDouble(边_c.getText());
if(a+b>c&&a+c>b&&c+b>a)
{ double p=(a+b+c)/2;
area=Math.sqrt(p*(p-a)(p-b)(p-c));//计算三角形的面积
结果.setText(""+area);
}
else
{ 结果.setText(“您输入的数字不能形成三角形”);
}
}
catch(Exception ee)
{ 结果.setText(“请输入数字字符”);
}
}
}
class Win extends Frame implements ActionListener
{ MenuBar bar=null; Menu menu=null;
MenuItem item1, item2;
圆 circle ;
三角形 trangle;
Win()
{ bar=new MenuBar();
menu=new Menu(“选择”);
item1=new MenuItem(“圆面积计算”);
item2=new MenuItem(“三角形面积计算”);
menu.add(item1);
menu.add(item2);
bar.add(menu);
setMenuBar(bar);
circle=new 圆(this,“计算圆的面积”,false);
trangle=new 三角形(this,“计算三角形的面积”,false);
item1.addActionListener(this);
item2.addActionListener(this);
setVisible(true);
setBounds(100,120,200,190);
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ System.exit(0);
}
}
);
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()==item1)
{ circle.setVisible(true);
}
else if(e.getSource()item2)
{ trangle.setVisible(true);
}
}
}
public class Example8_2
{ public static void main(String args[])
{ Win win=new Win();
}
}
例子3
import java.awt.;import java.awt.event.;
public class Example8_3
{ public static void main(String args[])
{ FWindow f=new FWindow(“窗口”);
}
}
class FWindow extends Frame implements ActionListener
{ FileDialog filedialog_save,
filedialog_load;//声明2个文件对话筐
MenuBar menubar;
Menu menu;
MenuItem itemSave,itemLoad;
TextArea text;
FWindow(String s)
{ super(s);
setSize(300,400);setVisible(true);
text=new TextArea(10,10);
add(text,“Center”); validate();
menubar=new MenuBar();menu=new Menu(“文件”);
itemSave=new MenuItem(“保存文件”); itemLoad=new MenuItem(“打开文件”);
itemSave.addActionListener(this); itemLoad.addActionListener(this);
menu.add(itemSave); menu.add(itemLoad);
menubar.add(menu);
setMenuBar(menubar);
filedialog_save=new FileDialog(this,“保存文件话框”,FileDialog.SAVE);
filedialog_save.setVisible(false);
filedialog_load=new FileDialog(this,“打开文件话框”,FileDialog.LOAD);
filedialog_load.setVisible(false);
filedialog_save.addWindowListener(new WindowAdapter()//对话框增加适配器
{ public void windowClosing(WindowEvent e)
{ filedialog_save.setVisible(false);
}
});
filedialog_load.addWindowListener(new WindowAdapter()//对话框增加适配器
{public void windowClosing(WindowEvent e)
{ filedialog_load.setVisible(false);
}
});
addWindowListener(new WindowAdapter() //窗口增加适配器
{public void windowClosing(WindowEvent e)
{ setVisible(false);System.exit(0);
}
});
}
public void actionPerformed(ActionEvent e) //实现接口中的方法
{ if(e.getSource()itemSave)
{ filedialog_save.setVisible(true);
String name=filedialog_save.getFile();
if(name!=null)
{ text.setText(“你选择了保存文件,名字是”+name);
}
else
{ text.setText(“没有保存文件”);
}
}
else if(e.getSource()itemLoad)
{ filedialog_load.setVisible(true);
String name=filedialog_load.getFile();
if(name!=null)
{ text.setText(“你选择了打开文件,名字是”+name);
}
else
{ text.setText(“没有打开文件”);
}
}
}
}
例子4
import java.awt.event.;
import java.awt.;
import javax.swing.JOptionPane;
class Dwindow extends Frame implements ActionListener
{ TextField inputNumber;
TextArea show;
Dwindow(String s)
{ super(s);
inputNumber=new TextField(22); inputNumber.addActionListener(this);
show=new TextArea();
add(inputNumber,BorderLayout.NORTH); add(show,BorderLayout.CENTER);
setBounds(60,60,300,300); setVisible(true);
validate();
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ System.exit(0);
}
}
);
}
public void actionPerformed(ActionEvent e)
{ boolean boo=false;
if(e.getSource()inputNumber)
{ String s=inputNumber.getText();
char a[]=s.toCharArray();
for(int i=0;i<a.length;i++)
{ if(!(Character.isDigit(a[i])))
boo=true;
}
if(bootrue) //弹出“警告”消息对话框
{ JOptionPane.showMessageDialog(this,“您输入了非法字符”,“警告对话框”,
JOptionPane.WARNING_MESSAGE);
inputNumber.setText(null);
}
else if(boofalse)
{ int number=Integer.parseInt(s);
show.append("\n"+number+“平方:”+(numbernumber));
}
}
}
}
public class Example8_4
{ public static void main(String args[])
{ new Dwindow(“带对话框的窗口”);
}
}
例子5
import java.awt.event.;
import java.awt.*;
import javax.swing.JOptionPane;
class Dwindow extends Frame
implements ActionListener
{ TextField inputName;
TextArea save;
Dwindow(String s)
{ super(s);
inputName=new TextField(22);
inputName.addActionListener(this);
save=new TextArea();
add(inputName,BorderLayout.NORTH);
add(save,BorderLayout.CENTER);
setBounds(60,60,300,300);
setVisible(true);
validate();
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ System.exit(0);
}
}
);
}
public void actionPerformed(ActionEvent e)
{ String s=inputName.getText();
int n=JOptionPane.showConfirmDialog(this,“确认正确吗？”,“确认对话框”,
JOptionPane.YES_NO_OPTION );
if(nJOptionPane.YES_OPTION)
{ save.append("\n"+s);
}
else if(nJOptionPane.NO_OPTION)
{ inputName.setText(null);
}
}
}
public class Example8_5
{ public static void main(String args[])
{ new Dwindow(“带对话框的窗口”);
}
}
例子6
import java.awt.event.;
import java.awt.;
import javax.swing.JColorChooser;
class Dwindow extends Frame implements ActionListener
{ Button button;
Dwindow(String s)
{ super(s);
button=new Button(“打开颜色对话框”);
button.addActionListener(this);
setLayout(new FlowLayout());
add(button);
setBounds(60,60,300,300);
setVisible(true);
validate();
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ System.exit(0);
}
}
);
}
public void actionPerformed(ActionEvent e)
{ Color newColor=JColorChooser.showDialog(this,“调色板”,button.getBackground());
button.setBackground(newColor);
}
}
public class Example8_6
{ public static void main(String args[])
{ new Dwindow(“带颜色对话框的窗口”);
}
}

第九章Java多线程机制
例子1
public class Example9_1
{ public static void main(String args[])
{ Lefthand left;
Righthand right;
left=new Lefthand() ; //创建线程
right=new Righthand();
left.start();
right.start();
for(int i=1;i<=6;i++)
{ System.out.println(“我是主线程”);
}
}
}
class Lefthand extends Thread
{ public void run()
{ for(int i=1;i<=9;i++)
{
System.out.println(“我是左手线程”);
}
}
}
class Righthand extends Thread
{ public void run()
{ for(int i=1;i<=9;i++)
{ System.out.println(“我是右手线程”);
}
}
}
例子2
public class Example9_2
{ public static void main(String args[])
{ People teacher,student;
ComputerSum sum=new ComputerSum();
teacher=new People(“老师”,200,sum);
student =new People(“学生”,200,sum);
teacher.start();
student.start();
}
}
class ComputerSum
{ int sum;
public void setSum(int n)
{ sum=n;
}
public int getSum()
{ return sum;
}
}
class People extends Thread
{ int timeLength; //线程休眠的时间长度
ComputerSum sum;
People(String s,int timeLength,ComputerSum sum)
{ setName(s); //调用Thread类的方法setName为线程起个名字
this.timeLength=timeLength;
this.sum=sum;
}
public void run()
{ for(int i=1;i<=5;i++)
{ int m=sum.getSum();
sum.setSum(m+1);
System.out.println(“我是”+getName()+",现在的和:"+sum.getSum());
try { sleep(timeLength);
}
catch(InterruptedException e){}
}
}
}
例子3
public class Example9_3
{ public static void main(String args[ ])
{ Bank bank=new Bank();
//线程的目标对象设置被线程共享的money
bank.setMoney(300);
bank.会计.start();
bank.出纳.start();
}
}
class Bank implements Runnable
{ private int money=0;
Thread 会计,出纳;
Bank()
{ 会计=new Thread(this);
会计.setName(“会计”);
出纳=new Thread(this); //会计和出纳的目标对象相同
出纳.setName(“出纳”);
}
public void setMoney(int mount)
{ money=mount;
}
public void run() //接口中的方法
{ while(true)
{ money=money-50;
if(Thread.currentThread()会计)
{ System.out.println(“我是”+会计.getName()+“现在有:”+money+“元”);
if(money<=150)
{ System.out.println(会计.getName()+“进入死亡状态”);
return; //如果money少于50, 会计的run方法结束
}
}
else if(Thread.currentThread()出纳)
{ System.out.println(“我是”+出纳.getName()+“现在有:”+money+“元”);
if(money<=0)
return; //如果money少于0, 出纳的run方法结束
}
try{ Thread.sleep(800);
}
catch(InterruptedException e){}
}
}
}
例子4
class Example9_4
{ public static void main(String args[ ])
{ Thread threadA,threadB,threadC,threadD;
TargetObject a1=new TargetObject(), //线程的目标对象
a2=new TargetObject();
threadA=new Thread(a1); //目标对象是a1的线程
threadB=new Thread(a1);
a1.setNumber(10);
threadA.setName(“add”);
threadB.setName(“add”);
threadC=new Thread(a2); //目标对象是a2的线程
threadD=new Thread(a2);
a2.setNumber(-10);
threadC.setName(“sub”);
threadD.setName(“sub”);
threadA.start();
threadB.start();
threadC.start();
threadD.start();
}
}
class TargetObject implements Runnable
{
private int number=0;
public void setNumber(int n)
{ number=n;
}
public void run()
{ while(true)
{ if(Thread.currentThread().getName().equals(“add”))
{ number++;
System.out.println(“现在number等于”+number);
}
if(Thread.currentThread().getName().equals(“sub”))
{ number–;
System.out.println(“现在number等于”+number);
}
try{ Thread.sleep(1000);
}
catch(InterruptedException e)
{
}
}
}
}
例子5
class Example9_5
{ public static void main(String args[])
{ Move move=new Move();
move.zhangsan.start();
move.lisi.start();
}
}
class Move implements Runnable
{ Thread zhangsan,lisi;
Move()
{ zhangsan=new Thread(this);
zhangsan.setName(“张三”);
lisi=new Thread(this);
lisi.setName(“李四”);
}
public void run()
{ int i=0;
while(i<=5)
{ if(Thread.currentThread()zhangsan)
{ i=i+1;
System.out.println(zhangsan.getName()+“线程的局部变量i=”+i);
}
else if(Thread.currentThread()lisi)
{ i=i+1;
System.out.println(lisi.getName()+“线程的局部变量i=”+i);
}
try{ Thread.sleep(800);
}
catch(InterruptedException e){}
}
}
}
例子6
public class Example9_6
{ public static void main(String args[])
{ Number number=new Number();
number.giveNumberThread.start();
number.guessNumberThread.start();
}
}
class Number implements Runnable
{
int realNumber,guessNumber,min=0,max=100,message;
final int SMALLER=-1,LARGER=1,SUCCESS=8;
Thread giveNumberThread,guessNumberThread;
Number()
{ giveNumberThread=new Thread(this);
guessNumberThread=new Thread(this);
}
public void run()
{
for(int count=1;true;count++)
{
if(Thread.currentThread()giveNumberThread)
{
if(count1)
{ realNumber=(int)(Math.random()*100)+1;
System.out.println(“随机给你一个数，猜猜是多少？”);
}
else
{ if(realNumber>guessNumber)
{ message=SMALLER;
System.out.println(“你猜小了”);
}
else if(realNumber<guessNumber)
{ message=LARGER;
System.out.println(“你猜大了”);
}
else
{ message=SUCCESS;
System.out.println(“恭喜，你猜对了”);
return;
}
}
try{ Thread.sleep(1500);
}
catch(Exception e){}
}
if(Thread.currentThread()guessNumberThread)
{
if(count1)
{ guessNumber=(min+max)/2;
System.out.println(“我第”+count+“次猜这个数是:”+guessNumber);
}
else
{ if(messageSMALLER)
{ min=guessNumber;
guessNumber=(min+max)/2;
System.out.println(“我第”+count+“次猜这个数是:”+guessNumber);
}
else if(messageLARGER)
{ max=guessNumber;
guessNumber=(min+max)/2;
System.out.println(“我第”+count+“次猜这个数是:”+guessNumber);
}
else if(messageSUCCESS)
{ System.out.println(“我成功了！”);
return;
}
}
try{ Thread.sleep(1500);
}
catch(Exception e){}
}
}
}
}
例子7
class Example9_7
{ public static void main(String args[ ])
{ ComputerSum sum=new ComputerSum();
sum.computer1.start();
}
}
class ComputerSum implements Runnable
{
Thread computer1,computer2;
int i=1,sum=0;
ComputerSum()
{ computer1=new Thread(this);
computer2=new Thread(this);
}
public void run()
{ while(i<=10)
{ sum=sum+i;
System.out.println(sum);
i++;
if(i6&&Thread.currentThread()computer1)
{ System.out.println(computer1.getName()+“完成任务了！”);
computer2.start();
return;
}
}
}
}
例子8
import java.util.*;
public class Example9_8
{ public static void main(String args[ ])
{ A a=new A();
a.thread.start();
}
}
class A implements Runnable
{ Thread thread;
int n=0;
A()
{ thread=new Thread(this);
}
public void run()
{ while(true)
{ System.out.println(new Date());
n++;
try{ Thread.sleep(1000);
}
catch(InterruptedException e){}
if(n3)
{ thread=new Thread(this);
thread.start();
}
if(n>=12)
return;
}
}
}
例子9
public class Example9_9
{ public static void main(String args[])
{ A a=new A();
a.student.start();
a.teacher.start();
}
}
class A implements Runnable
{ Thread student,teacher;
A()
{ teacher=new Thread(this);
student=new Thread(this);
teacher.setName(“王教授”);
student.setName(“张三”);
}
public void run()
{ if(Thread.currentThread()student)
{ try{ System.out.println(student.getName()+“正在睡觉，不听课”);
Thread.sleep(10006060);
}
catch(InterruptedException e)
{ System.out.println(student.getName()+“被老师叫醒了”);
}
System.out.println(student.getName()+“开始听课”);
}
else if(Thread.currentThread()teacher)
{
for(int i=1;i<=3;i++)
{ System.out.println(“上课!”);
try{ Thread.sleep(500);
}
catch(InterruptedException e){}
}
student.interrupt(); //吵醒student
}
}
}
例子10
import java.awt.;
import java.awt.event.;
public class Example9_10
{ public static void main(String args[])
{ new ThreadFrame();
}
}
class ThreadFrame extends Frame implements ActionListener,Runnable
{ TextField text1,text2;
boolean boo;
Label label=
new Label(“欢迎使用本字典”);
Button fast=new Button(“加速”);
Thread Scrollwords=null;
ThreadFrame()
{ setLayout(new FlowLayout());
Scrollwords=new Thread(this);
text1=new TextField(10);
text2=new TextField(10);
add(text1);
add(text2);
add(fast);
add(label);
text1.addActionListener(this);
fast.addActionListener(this);
setBounds(100,100,400,280);
setVisible(true);
validate();
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ System.exit(0);
}
});
Scrollwords.start();
}
public void run()
{ while(true)
{ int x=label.getBounds().x;
int y=120;
x=x+5;
label.setLocation(x,y);
if(x>380)
{ x=10;
label.setLocation(x,y);
}
try{ Scrollwords.sleep(1000);
}
catch(InterruptedException e){}
if(boo)
{ return; //结束run方法，导致线程死亡。
}
}
}
public void actionPerformed(ActionEvent e)
{ if(text1.getText().equals(“boy”))
{ text2.setText(“男孩”);
}
else if(text1.getText().equals(“die”))
{ boo=true;
}
else
{ text2.setText(“没有该单词”);
}
if(e.getSource()fast)
{ Scrollwords.interrupt(); //吵醒休眠的线程，以便加快字模的滚动
}
}
}
例子11
import java.awt.;
import java.awt.event.;
public class Example9_11
{ public static void main(String args[])
{ MyFrame frame=new MyFrame();
frame.setBounds(10,10,500,500) ;
frame.setVisible(true);
frame.addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ System.exit(0);
}
});
}
}
class MyFrame extends Frame implements Runnable
{ Thread 红色球,兰色球;
MyCanvas red,blue;
double t=0;
MyFrame()
{ 红色球=new Thread(this);
兰色球=new Thread(this);
red=new MyCanvas(Color.red);
blue=new MyCanvas(Color.blue);
setLayout(null);
add(red);
add(blue);
red.setLocation(60,100);
blue.setLocation(60,100);
红色球.start();
兰色球.start();
}
public void run()
{ while(true)
{ t=t+0.2;
if(t>20) t=0;
if(Thread.currentThread()红色球)
{ int x=60;
int h=(int)(1.0/2tt3.8)+60;
red.setLocation(x,h);
try{ 红色球.sleep(50);
}
catch(InterruptedException e){}
}
else if(Thread.currentThread()==兰色球)
{ int x=60+(int)(26t);
int h=(int)(1.0/2tt3.8)+60;
blue.setLocation(x,h);
try{ 兰色球.sleep(50);
}
catch(InterruptedException e){}
}
}
}
}
class MyCanvas extends Canvas
{
Color c;
MyCanvas(Color c)
{ setSize(20,20);
this.c=c;
}
public void paint(Graphics g)
{ g.setColor©;
g.fillOval(0,0,20,20);
}
}
例子12
import java.awt.event.;
import java.awt.;
import java.util.Date;
public class Example9_12
{ public static void main(String args[])
{ new Win();
}
}
class Win extends Frame
implements Runnable,ActionListener
{ Thread thread=null;
TextArea text=null;
Button buttonStart=new Button(“Start”),
buttonStop=new Button(“Stop”);
boolean die;
Win()
{ thread=new Thread(this);
text=new TextArea();
add(text,BorderLayout.CENTER);
Panel p=new Panel();
p.add(buttonStart);
p.add(buttonStop);
buttonStart.addActionListener(this);
buttonStop.addActionListener(this) ;
add(p,BorderLayout.NORTH);
setVisible(true);
setSize(500,500);
validate();
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{System.exit(0);
}
});
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()==buttonStart)
{ if(!(thread.isAlive()))
{ thread=new Thread(this);
die=false;
}
try { thread.start();
}
catch(Exception e1)
{ text.setText(“线程没有结束run方法之前,不要再调用start方法”);
}
}
else if(e.getSource()buttonStop)
{ die=true;
}
}
public void run()
{ while(true)
{ text.append("\n"+new Date());
try{ thread.sleep(1000);
}
catch(InterruptedException ee){}
if(dietrue)
return;
}
}
}
例子13
import java.awt.;
import java.awt.event.;
public class Example9_13
{ public static void main(String args[])
{ new FrameMoney();
}
}
class FrameMoney extends Frame
implements Runnable,ActionListener
{ int money=100;
TextArea text1,text2;
Thread 会计,出纳;
int weekDay;
Button start=new Button(“开始演示”);
FrameMoney()
{ 会计=new Thread(this);
出纳=new Thread(this);
text1=new TextArea(12,15);
text2=new TextArea(12,15);
setLayout(new FlowLayout());
add(start);
add(text1);
add(text2);
setVisible(true);
setSize(360,300);
validate();
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{System.exit(0);
}
});
start.addActionListener(this);
}
public void actionPerformed(ActionEvent e)
{ if(!(出纳.isAlive()))
{ 会计=new Thread(this);
出纳=new Thread(this);
}
try
{ 会计.start();
出纳.start();
}
catch(Exception exp){}
}
public synchronized void 存取(int number) //存取方法
{ if(Thread.currentThread()==会计)
{ text1.append(“今天是星期”+weekDay+"\n");
for(int i=1;i<=3;i++) //会计使用存取方法存入90元，存入30元，稍歇一下
{ money=money+number; //这时出纳仍不能使用存取方法
try { Thread.sleep(1000); //因为会计还没使用完存取方法
}
catch(InterruptedException e){}
text1.append(“帐上有”+money+“万\n”);
}
}
else if(Thread.currentThread()==出纳)
{ text2.append(“今天是星期 “+weekDay+”\n”);
for(int i=1;i<=2;i++) //出纳使用存取方法取出30元，取出15元，稍歇一下
{ money=money-number/2; //这时会计仍不能使用存取方法
try { Thread.sleep(1000); //因为出纳还没使用完存取方法
}
catch(InterruptedException e){}
text2.append(“帐上有”+money+“万\n”);
}
}
}
public void run()
{ if(Thread.currentThread()==会计||Thread.currentThread()==出纳)
{ for(int i=1;i<=3;i++) //从周一到周三会计和出纳都要使用帐本
{ weekDay=i;
存取(30);
}
}
}
}
例子14
import java.awt.;
import java.awt.event.*;
public class Example9_14
{ public static void main(String args[])
{ new MyFrame();
}
}
class MyFrame extends Frame
implements Runnable,ActionListener
{ 售票员 王小姐;
Thread 张平,李明;
static TextArea text;
Button start=new Button(“排队买票”);
MyFrame()
{ 王小姐=new 售票员();
张平=new Thread(this);
李明=new Thread(this);
text=new TextArea(10,30);
start.addActionListener(this);
add(text,BorderLayout.CENTER);
add(start,BorderLayout.NORTH);
setVisible(true);
setSize(360,300);
validate();
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{System.exit(0);
}
});
}
public void actionPerformed(ActionEvent e)
{ try{ 张平.start();
李明.start();
}
catch(Exception exp) {}
}
public void run()
{ if(Thread.currentThread()张平)
{ 王小姐.售票规则(20);
}
else if(Thread.currentThread()李明)
{ 王小姐.售票规则(5);
}
}
}
class 售票员
{ int 五元钱的个数=2,十元钱的个数=0,二十元钱的个数=0;
String s=null;
public synchronized void 售票规则(int money)
{ if(money5) //如果使用该方法的线程传递的参数是5,就不用等待
{ 五元钱的个数=五元钱的个数+1;
s= “给您入场卷您的钱正好”;
MyFrame.text.append("\n"+s);
}
else if(money20)
{ while(五元钱的个数<3)
{ try { wait(); //如果使用该方法的线程传递的参数是20须等待
}
catch(InterruptedException e){}
}
五元钱的个数=五元钱的个数-3;
二十元钱的个数=二十元钱的个数+1;
s=“给您入场卷”+" 您给我20，找您15元";
MyFrame.text.append("\n"+s);
}
notifyAll();
}
}
例子15
class A implements Runnable
{ int i=0;
String name;
public void run()
{ while(true)
{ i++;
System.out.println(name+“i=”+i);
if(i5)
{ try{ 挂起线程();
}
catch(Exception e){}
}
try{ Thread.sleep(1000);
}
catch(Exception e){}
}
}
public synchronized void 挂起线程() throws InterruptedException
{ wait();
}
public synchronized void 恢复线程()
{ notifyAll();
}
}
public class Example9_15
{ public static void main(String args[])
{ int m=0;
A target=new A(); //线程的目标对象
target.name=“张三”;
Thread thread=new Thread(target);
thread.setName(target.name);
thread.start();
while(true)
{ m++;
System.out.println(“我是主线程m=”+m);
if(m20)
{ System.out.println(“让”+thread.getName()+“继续工作”);
try { target.恢复线程(); //主线程占有CPU资源期间
} //让thread的目标对象调用notifyAll()
catch(Exception e){}
break;
}
try{ Thread.sleep(1000);
}
catch(Exception e){}
}
}
}
例子16
class MyThread extends Thread
{ int i=0;
public void run()
{ while(true)
{ i++;
System.out.println(“我的名字是”+getName()+“i=”+i);
if(i10)
{ try{ 挂起线程();
}
catch(Exception e){}
}
try{ Thread.sleep(1000);
}
catch(Exception e){}
}
}
public synchronized void 挂起线程() throws InterruptedException
{ wait();
}
public synchronized void 恢复线程()
{ notifyAll();
}
}
class YourThread extends Thread
{ int m=0;
MyThread otherThread;
YourThread(MyThread a)
{ otherThread=a;
}
public void run()
{ while(true)
{ m++;
System.out.println(“我的名字是”+getName()+“m=”+m);
if(m20)
{ System.out.println(“恢复线程: “+otherThread.getName());
System.out.println(getName()+“停止工作”);
try{ otherThread.恢复线程();
}
catch(Exception e){}
return;
}
try{ Thread.sleep(1000);
}
catch(Exception e){}
}
}
}
public class Example9_16
{ public static void main(String args[])
{ MyThread thread1=new MyThread();
thread1.setName(“张三”);
thread1.start();
YourThread thread2=new YourThread(thread1);
thread2.setName(“李四”);
thread2.start();
}
}
例子17
import java.awt.;
import java.awt.event.;
public class Example9_17
{ public static void main(String args[])
{ Win win=new Win();
}
}
class Win extends Frame implements
Runnable,ActionListener
{ Thread moveOrStop;
Button 开始,挂起,恢复,终止;
Label moveLabel;
boolean move=false,die=false;
Win()
{ moveOrStop=new Thread(this);
开始=new Button(“线程开始”);
挂起=new Button(“线程挂起”);
恢复=new Button(“线程恢复”);
终止=new Button(“线程终止”);
开始.addActionListener(this);
挂起.addActionListener(this);
恢复.addActionListener(this);
终止.addActionListener(this);
moveLabel=new Label(“线程负责运动我”);
moveLabel.setBackground(Color.cyan);
setLayout(new FlowLayout());
add(开始); add(挂起);
add(恢复); add(终止);
add(moveLabel);
setSize(200,300);
validate();
setVisible(true);
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ System.exit(0);
}
});
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()==开始)
{ try { move=true;
moveOrStop.start();
}
catch(Exception event) {}
}
else if(e.getSource()==挂起)
{ move=false;
}
else if(e.getSource()==恢复)
{ move=true;
恢复线程();
}
else if(e.getSource()终止)
{ die=true;
}
}
public void run()
{ while(true)
{
while(!move) //如果 move是false,挂起线程。
{ try{ 挂起线程();
}
catch(InterruptedException e1) { }
}
int x=moveLabel.getBounds().x;
int y=moveLabel.getBounds().y;
y=y+2;
if(y>=200) y=10;
moveLabel.setLocation(x,y);
try{ moveOrStop.sleep(200);
}
catch(InterruptedException e2) { }
if(dietrue)
{ return; //终止线程。
}
}
}
public synchronized void 挂起线程() throws InterruptedException
{ wait();
}
public synchronized void 恢复线程()
{ notifyAll();
}
}
例子18
import java.awt.;
import java.awt.event.;
import javax.swing.Timer;
public class Example9_18
{ public static void main(String args[])
{ TimeWin Win=new TimeWin();
}
}
class TimeWin extends Frame implements ActionListener
{ TextField text;
Button bStart,bStop,bContinue;
Timer time;
int n=0,start=1;
TimeWin()
{time=new Timer(1000,this);//TimeWin对象做计时器的监视器。
text=new TextField(10);
bStart=new Button(“开始计时”);
bStop=new Button(“暂停计时”);
bContinue=new Button(“继续计时”);
bStart.addActionListener(this);
bStop.addActionListener(this);
bContinue.addActionListener(this);
setLayout(new FlowLayout());
add(bStart);
add(bStop);
add(bContinue);
add(text);
setSize(500,500);
validate();
setVisible(true);
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ System.exit(0);
}
} );
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()==time)
{ java.util.Date date=new java.util.Date();
String str=date.toString().substring(11,19);
text.setText(“时间：”+str);
int x=text.getBounds().x;
int y=text.getBounds().y;
y=y+2;
text.setLocation(x,y);
}
else if(e.getSource()==bStart)
{ time.start();
}
else if(e.getSource()==bStop)
{ time.stop();
}
else if(e.getSource()==bContinue)
{ time.restart();
}
}
}
例子19
public class Example9_19
{ public static void main(String args[ ])
{ ThreadJoin a=new ThreadJoin();
a.customer.start();
a.tvMaker.start();
}
}
class ThreadJoin implements Runnable
{ TV tv;
Thread customer,tvMaker;
ThreadJoin()
{ customer=new Thread(this);
tvMaker=new Thread(this);
customer.setName(“顾客”);
tvMaker.setName(“电视制造厂”);
}
public void run()
{ if(Thread.currentThread()==customer)
{
System.out.println(customer.getName()+“等”+tvMaker.getName()+“生产电视”);
try{ tvMaker.join(); //线程customer开始等待tvMaker结束
}
catch(InterruptedException e){}
System.out.println(customer.getName()+
“买了一台电视：”+tv.name+” 价钱:”+tv.price);
}
else if(Thread.currentThread()==tvMaker)
{ System.out.println(tvMaker.getName()+“开始生产电视,请等…”);
try { tvMaker.sleep(2000);
}
catch(InterruptedException e){}
tv=new TV(“红星牌”,3288) ;
System.out.println(tvMaker.getName()+“生产完毕”);
}
}
}
class TV
{ float price;
String name;
TV(String name,float price)
{ this.name=name;
this.price=price;
}
}
例子20
public class Example9_20
{ public static void main(String args[ ])
{ Daemon a=new Daemon ();
a.A.start();
a.B.setDaemon(true);
a.B.start();
}
}
class Daemon implements Runnable
{ Thread A,B;
Daemon()
{ A=new Thread(this);
B=new Thread(this);
}
public void run()
{ if(Thread.currentThread()==A)
{ for(int i=0;i<8;i++)
{ System.out.println(“i=”+i) ;
try { Thread.sleep(1000);
}
catch(InterruptedException e) {}
}
}
else if(Thread.currentThread()==B)
{ while(true)
{ System.out.println("线程B是守护线程 ");
try { Thread.sleep(1000);
}
catch(InterruptedException e){}
}
}
}
}

第十章输入输出流
例子1
import java.io.;
public class Example10_1
{ public static void main(String args[])
{ File f1=new File(“F:\8000”,“Example20_1.java”);
File f2=new File(“F:\8000”);
System.out.println(“文件Example20_1是可读的吗:”+f1.canRead());
System.out.println(“文件Example20_1的长度:”+f1.length());
System.out.println(“文件Example20_1的绝对路径:”+f1.getAbsolutePath());
System.out.println(“F:\8000:是目录吗？”+f2.isDirectory());
}
}
例子2
import java.io.;
class FileAccept implements FilenameFilter
{ String str=null;
FileAccept(String s)
{ str="."+s;
}
public boolean accept(File dir,String name)
{ return name.endsWith(str);
}
}
public class Example10_2
{ public static void main(String args[ ])
{ File dir=new File(“E:\chaper9”);
File deletedFile=new File(dir,“E.java”);
FileAccept acceptCondition=new FileAccept(“java”);
File fileName[]=dir.listFiles(acceptCondition);
for(int i=0;i< fileName.length;i++)
{ System.out.println(“文件名称:”+fileName[i].getName());
}
boolean boo=deletedFile.delete();
if(boo)
{ System.out.println(“文件:”+deletedFile.getName()+“被删除”);
}
}
}
例子3
import java.awt.;
import java.io.;
import java.awt.event.;
public class Example10_3
{ public static void main(String args[])
{ try{
Runtime ce=Runtime.getRuntime();
ce.exec(“javac Example9_18.java”);
ce.exec(“java Example9_18”);
File file=new File(“c:/windows”,“Notepad.exe”);
ce.exec(file.getAbsolutePath());
}
catch(Exception e)
{ System.out.println(e);
}
}
}
例子4
import java.io.;
import java.awt.;
import java.awt.event.;
public class Example10_4
{ public static void main(String args[])
{ int b;
byte tom[]=new byte[25];
try{ File f=new File(“Example10_3.java”);
FileInputStream in=new FileInputStream(f);
while((b=in.read(tom,0,25))!=-1)
{ String s=new String (tom,0,b);
System.out.print(s);
}
in.close();
}
catch(IOException e)
{ System.out.println(“File read Error”+e);
}
}
}
例子5
import java.io.;
public class Example10_5
{ public static void main(String args[])
{ int b;
byte buffer[]=new byte[100];
try{ System.out.println(“输入一行文本，并存入磁盘：”);
b=System.in.read(buffer); //把从键盘敲入的字符存入buffer
FileOutputStream writefile=new FileOutputStream(“line.txt”);
writefile.write(buffer,0,b); // 通过流把 buffer写入到文件line.txt
}
catch(IOException e)
{ System.out.println("Error "+e);
}
}
}
例子6
import java.io.;
import java.awt.;
import java.awt.event.;
public class Example10_6
{ public static void main(String args[])
{ char a[]=
“今晚10点发起总攻”.toCharArray();
int n=0,m=0;
try{ File f=new File(“secret.txt”);
for(int i=0;i<a.length;i++)
{ a[i]=(char)(a[i]^‘R’);
}
FileWriter out=new FileWriter(f);
out.write(a,0,a.length);
out.close();
FileReader in=new FileReader(f);
char tom[]=new char[10];
System.out.println(“密文:”);
while((n=in.read(tom,0,10))!=-1)
{ String s=new String (tom,0,n);
System.out.print(s);
}
in.close();
in=new FileReader(f);
System.out.println("");
System.out.println(“明文:”);
while((n=in.read(tom,0,10))!=-1)
{ for(int i=0;i<n;i++)
{ tom[i]=(char)(tom[i]^‘R’);
}
String s=new String (tom,0,n);
System.out.print(s);
}
in.close();
}
catch(IOException e)
{ System.out.println(“File read Error”);
}
}
}
例子7
import java.io.;
public class Example10_7
{ public static void main(String args[ ])
{ File file=new File(“Student.txt”);
String content[]=
{“你好:”,“近来工作忙吗?”,“常联系”,“祝好”};
try{ FileWriter outOne=new FileWriter(file);
BufferedWriter outTwo= new BufferedWriter(outOne);
for(int k=0;k<content.length;k++)
{ outTwo.write(content[k]);
outTwo.newLine();
}
outTwo.close();
outOne.close();
FileReader inOne=new FileReader(file);
BufferedReader inTwo= new BufferedReader(inOne);
String s=null;
int i=0;
while((s=inTwo.readLine())!=null)
{ i++;
System.out.println(“第”+i+“行:”+s);
}
inOne.close();
inTwo.close();
}
catch(IOException e)
{ System.out.println(e);
}
}
}
例子8
import java.util.;
import java.io.;
import java.awt.;
import java.awt.event.;
import javax.swing.;
public class Example10_8
{ public static void main(String args[])
{ EWindow w=new EWindow();
w.validate();
}
}
class EWindow extends Frame implements ActionListener,ItemListener
{ String str[]=new String[7],s;
FileReader file;
BufferedReader in;
Button start,next;
Checkbox checkbox[];
TextField 题目,分数;
int score=0;
CheckboxGroup age=new CheckboxGroup();
EWindow()
{ super(“英语单词学习”);
分数=new TextField(10);题目=new TextField(70);
start=new Button(“重新练习”);
start.addActionListener(this);
next=new Button(“下一题目”);
next.addActionListener(this);
checkbox=new Checkbox[4];
for(int i=0;i<=3;i++)
{ checkbox[i]=new Checkbox("",false,age);
checkbox[i].addItemListener(this);
}
try { file=new FileReader(“English.txt”);
in=new BufferedReader(file);
}
catch(IOException e){}
setBounds(20,100,660,300); setVisible(true);
Box box=Box.createVerticalBox();
Panel p1=new Panel(),p2=new Panel(),
p3=new Panel() ,p4=new Panel(),p5=new Panel();
p1.add(new Label(“题目:”));p1.add(题目);
p2.add(new Label(“选择答案：”));
for(int i=0;i<=3;i++)
{ p2.add(checkbox[i]);
}
p3.add(new Label(“您的得分:”));p3.add(分数);
p4.add(start); p4.add(next);
box.add(p1);box.add(p2);box.add(p3);box.add(p4);
addWindowListener(new WindowAdapter()
{public void windowClosing(WindowEvent e)
{ System.exit(0);
}

                    });
 add(box,BorderLayout.CENTER);
 reading();

}
public void reading()
{ int i=0;
try { s=in.readLine();
if(!(s.startsWith(“endend”)))
{ StringTokenizer tokenizer=new StringTokenizer(s,"#");
while(tokenizer.hasMoreTokens())
{ str[i]=tokenizer.nextToken();
i++;
}
题目.setText(str[0]);
for(int j=1;j<=4;j++)
{ checkbox[j-1].setLabel(str[j]);
}
}
else if(s.startsWith(“endend”))
{ 题目.setText(“学习完毕”);
for(int j=0;j<4;j++)
{ checkbox[j].setLabel(“end”);
in.close();file.close();
}
}
}
catch(Exception exp){ 题目.setText(“无试题文件”) ; }
}
public void actionPerformed(ActionEvent event)
{ if(event.getSource()==start)
{ score=0;
分数.setText("得分： "+score);
try { file=new FileReader(“English.txt”);
in=new BufferedReader(file);
}
catch(IOException e){}
reading();
}
if(event.getSource()==next)
{ reading();
for(int j=0;j<4;j++)
{ checkbox[j].setEnabled(true);
}
}
}
public void itemStateChanged(ItemEvent e)
{ for(int j=0;j<4;j++)
{ if(checkbox[j].getLabel().equals(str[5])&&checkbox[j].getState())
{ score++;
分数.setText("得分： "+score);
}
checkbox[j].setEnabled(false);
}
}
}
例子9
import java.awt.;import java.io.;
import java.awt.event.;
public class Example10_9
{ public static void main(String args[])
{ FileWindows win=new FileWindows();
}
}
class FileWindows extends Frame implements ActionListener
{ FileDialog filedialog_save,filedialog_load;//声明2个文件对话筐
MenuBar menubar;
Menu menu;
MenuItem itemOpen,itemSave;
TextArea text;
BufferedReader in;
FileReader file_reader;
BufferedWriter out;
FileWriter tofile;
FileWindows()
{ super(“带文件对话框的窗口”);
setSize(260,270);
setVisible(true);
menubar=new MenuBar();
menu=new Menu(“文件”);
itemOpen=new MenuItem(“打开文件”);
itemSave=new MenuItem(“保存文件”);
itemOpen.addActionListener(this);
itemSave.addActionListener(this);
menu.add(itemOpen);
menu.add(itemSave);
menubar.add(menu);
setMenuBar(menubar);
filedialog_save=new FileDialog(this,“保存文件话框”,FileDialog.SAVE);
filedialog_load=new FileDialog(this,“打开文件话框”,FileDialog.LOAD);
filedialog_save.addWindowListener(new WindowAdapter()
{public void windowClosing(WindowEvent e)
{ filedialog_save.setVisible(false);
}
});
filedialog_load.addWindowListener(new WindowAdapter()//对话框增加适配器
{public void windowClosing(WindowEvent e)
{ filedialog_load.setVisible(false);
}
});
addWindowListener(new WindowAdapter()
{public void windowClosing(WindowEvent e)
{ System.exit(0);}
});
text=new TextArea(10,10);
add(text,BorderLayout.CENTER);
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()==itemOpen)
{ filedialog_load.setVisible(true);
text.setText(null);
String s;
if(filedialog_load.getFile()!=null)
{ try{ File file= new
File(filedialog_load.getDirectory(),filedialog_load.getFile());
file_reader=new FileReader(file);
in=new BufferedReader(file_reader);
while((s=in.readLine())!=null)
text.append(s+’\n’);
in.close();
file_reader.close();
}
catch(IOException e2){}
}
}
else if(e.getSource()==itemSave)
{ filedialog_save.setVisible(true);
if(filedialog_save.getFile()!=null)
{ try { File file=new
File(filedialog_save.getDirectory(),filedialog_save.getFile());
tofile=new FileWriter(file);
out=new BufferedWriter(tofile);
out.write(text.getText(),0,(text.getText()).length());
out.close();
tofile.close();
}
catch(IOException e2){}
}
}
}
}
例子10
import java.io.;
public class Example10_10
{ public static void main(String args[])
{ RandomAccessFile in_and_out=null;
int data[]={1,2,3,4,5,6,7,8,9,10};
try{ in_and_out=new RandomAccessFile(“tom.dat”,“rw”);
}
catch(Exception e){}
try{ for(int i=0;i<data.length;i++)
{ in_and_out.writeInt(data[i]);
}
for(long i=data.length-1;i>=0;i–)
{ in_and_out.seek(i4);
//每隔4个字节往前读取一个整数
System.out.print(","+in_and_out.readInt());
}
in_and_out.close();
}
catch(IOException e){}
}
}
例子11
import java.io.;
class Example10_11
{ public static void main(String args[])
{ try{ RandomAccessFile in=new RandomAccessFile(“Example10_11.java”,“rw”);
long filePoint=0;
long fileLength=in.length();
while(filePoint<fileLength)
{ String s=in.readLine();
System.out.println(s);
filePoint=in.getFilePointer();
}
in.close();
}
catch(Exception e){}
}
}

例子12
import java.io.;
import javax.swing.;
import java.awt.;
import java.awt.event.;
public class Example10_12
{ public static void main(String args[])
{ new CommFrame();
}
}
class InputArea extends Panel
implements ActionListener
{ File f=null;
RandomAccessFile out;
Box baseBox ,boxV1,boxV2;
TextField name,email,phone;
Button button;
InputArea(File f)
{ setBackground(Color.cyan);
this.f=f;
name=new TextField(12);
email=new TextField(12);
phone=new TextField(12);
button=new Button(“录入”);
button.addActionListener(this);
boxV1=Box.createVerticalBox();
boxV1.add(new Label(“输入姓名”));
boxV1.add(Box.createVerticalStrut(8));
boxV1.add(new Label(“输入email”));
boxV1.add(Box.createVerticalStrut(8));
boxV1.add(new Label(“输入电话”));
boxV1.add(Box.createVerticalStrut(8));
boxV1.add(new Label(“单击录入”));
boxV2=Box.createVerticalBox();
boxV2.add(name);
boxV2.add(Box.createVerticalStrut(8));
boxV2.add(email);
boxV2.add(Box.createVerticalStrut(8));
boxV2.add(phone);
boxV2.add(Box.createVerticalStrut(8));
boxV2.add(button);
baseBox=Box.createHorizontalBox();
baseBox.add(boxV1);
baseBox.add(Box.createHorizontalStrut(10));
baseBox.add(boxV2);
add(baseBox);
}
public void actionPerformed(ActionEvent e)
{ try{
RandomAccessFile out=new RandomAccessFile(f,“rw”);
if(f.exists())
{ long length=f.length();
out.seek(length);
}
out.writeUTF(“姓名:”+name.getText());
out.writeUTF(“eamil:”+email.getText());
out.writeUTF(“电话:”+phone.getText());
out.close();
}
catch(IOException ee){}
}
}
class CommFrame extends Frame implements ActionListener
{ File file=null;
MenuBar bar;
Menu fileMenu;
MenuItem 录入,显示;
TextArea show;
InputArea inputMessage;
CardLayout card=null; //卡片式布局.
Panel pCenter;
CommFrame()
{ file=new File(“通讯录.txt”);
录入=new MenuItem(“录入”);
显示=new MenuItem(“显示”);
bar=new MenuBar();
fileMenu=new Menu(“菜单选项”);
fileMenu.add(录入);
fileMenu.add(显示);
bar.add(fileMenu);
setMenuBar(bar);
录入.addActionListener(this);
显示.addActionListener(this);
inputMessage=new InputArea(file);
show=new TextArea(12,20);
card=new CardLayout();
pCenter=new Panel();
pCenter.setLayout(card);
pCenter.add(“录入”,inputMessage);
pCenter.add(“显示”,show);
add(pCenter,BorderLayout.CENTER);
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ System.exit(0);
}
});
setVisible(true);
setBounds(100,50,420,380);
validate();
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()==录入)
{ card.show(pCenter,“录入”);
}
else if(e.getSource()==显示)
{ int number=1;
show.setText(null);
card.show(pCenter,“显示”);
try{ RandomAccessFile in=new RandomAccessFile(file,“r”);
String 姓名=null;
while((姓名=in.readUTF())!=null)
{ show.append("\n"+number+" “+姓名);
show.append(in.readUTF()); //读取email.
show.append(in.readUTF()); //读取phone
show.append(”\n------------------------- “);
number++;
}
in.close();
}
catch(Exception ee){}
}
}
}
例子13
import java.io.;
public class Example20_13
{ public static void main(String args[])
{ try
{ FileOutputStream fos=new FileOutputStream(“jerry.dat”);
DataOutputStream out_data=new DataOutputStream(fos);
out_data.writeInt(100);out_data.writeInt(10012);
out_data.writeLong(123456);
out_data.writeFloat(3.1415926f); out_data.writeFloat(2.789f);
out_data.writeDouble(987654321.1234);
out_data.writeBoolean(true);out_data.writeBoolean(false);
out_data.writeChars(“i am ookk”);
}
catch(IOException e){}
try
{ FileInputStream fis=new FileInputStream(“jerry.dat”);
DataInputStream in_data=new DataInputStream(fis);
System.out.println(":"+in_data.readInt());//读取第1个int整数
System.out.println(":"+in_data.readInt());//读取第2个int整数
System.out.println(":"+in_data.readLong()); //读取long整数
System.out.println(":"+in_data.readFloat());//读取第1个float数
System.out.println(":"+in_data.readFloat());//读取第2个float数
System.out.println(":"+in_data.readDouble());
System.out.println(":"+in_data.readBoolean());//读取第1个boolean
System.out.println(":"+in_data.readBoolean());//读取第2个boolean
char c;
while((c=in_data.readChar())!=’\0’) //’\0’表示空字符
System.out.print©;
}
catch(IOException e){}
}
}
例子14
import java.io.;
public class Example10_14
{ public static void main(String args[])
{ int n=-1;
try{ ByteArrayOutputStream outByte=new ByteArrayOutputStream();
byte a[]=“你好，内存条!”.getBytes();
outByte.write(a);
outByte.close();
ByteArrayInputStream inByte=new ByteArrayInputStream(outByte.toByteArray());
byte tom[]=new byte[8];
while((n=inByte.read(tom,0,4))!=-1)
{ System.out.print(new String(tom,0,n));
}
inByte.close();
char jerry[]=new char[8];
CharArrayWriter outChar=new CharArrayWriter();
char b[]=“你的价钱如何？”.toCharArray();
outChar.write(b);
outChar.close();
CharArrayReader inChar=new CharArrayReader(outChar.toCharArray());
while((n=inChar.read(jerry,0,4))!=-1)
{ System.out.print(new String(jerry,0,n));
}
inChar.close();
}
catch(IOException e){}
}
}
例子15
import java.io.;
class Student implements Serializable//实现Serializable接口
{ String name=null;
double height;
Student(String name,double height)
{ this.name=name;
this.height=height;
}
public void setHeight (double c)
{ this.height=c;
}
}
public class Example10_15
{ public static void main(String args[])
{ Student zhang=new Student(“张三”,1.65);
try{
FileOutputStream file_out=new FileOutputStream(“s.txt”);
ObjectOutputStream object_out=new ObjectOutputStream(file_out);
object_out.writeObject(zhang);
FileInputStream file_in=new FileInputStream(“s.txt”);
ObjectInputStream object_in=new ObjectInputStream(file_in);
Student li=(Student)object_in.readObject();
li.setHeight(1.78); //设置身高。
li.name=“李四”;
System.out.println(zhang.name+" 身高是："+zhang.height);
System.out.println(li.name+" 身高是："+li.height);
}
catch(ClassNotFoundException event)
{ System.out.println(“不能读出对象”);
}
catch(IOException event)
{ System.out.println(“can not read file”+event);
}
}
}
例子16
import java.io.;
class GetCloneObject
{ public Object getClone(Object a)
{ Object object=null;
try{
ByteArrayOutputStream outOne=new ByteArrayOutputStream();
ObjectOutputStream outTwo=new ObjectOutputStream(outOne);
outTwo.writeObject(a);
ByteArrayInputStream inOne=new ByteArrayInputStream(outOne.toByteArray());
ObjectInputStream inTwo=new ObjectInputStream(inOne);
object=inTwo.readObject();
}
catch(Exception event)
{ System.out.println(event);
}
return object;
}
}
class Student implements Serializable
{ String number=null;
double height;
Student(String number,double height)
{ this.number=number;
this.height=height;
}
public void setHeight (double c)
{ this.height=c;
}
public void setNumber(String number)
{ this.number=number;
}
}
class School
{ public void setStudent(Student s,String number,double m)
{ s.setNumber(number);
s.setHeight(m);
}
}
public class Example10_16
{ public static void main(String args[])
{ try
{ GetCloneObject cloneObject=new GetCloneObject();
School school=new School();
Student student=new Student(“0000000”,0.0);
Student studentClone=(Student)cloneObject.getClone(student);
school.setStudent(studentClone,“2006001”,1.78);
System.out.println(student.number+” 身高:"+student.height);
System.out.println(studentClone.number+" 身高:"+studentClone.height);
}
catch(Exception e){}
}
}
例子17
import java.awt.;
import java.awt.event.;
import java.io.;
public class Example10_17
{ public static void main(String args[])
{ MyWin win=new MyWin();
}
}
class MyWin extends Frame
implements ActionListener
{ TextArea text=null;
Button 读入=null,写出=null;
FileInputStream inOne=null;
FileOutputStream outOne=null;
ObjectInputStream inTwo=null;
ObjectOutputStream outTwo=null;
MyWin()
{ setLayout(new FlowLayout());
text=new TextArea(6,10);
读入=new Button(“读入对象”);
写出=new Button(“写出对象”);
读入.addActionListener(this);
写出.addActionListener(this);
text.addTextListener(new Boy(text));
setVisible(true);
add(text);add(读入);
add(写出);
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ System.exit(0);
}
});
setSize(300,300);
validate();
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()==写出)
{ try{ outOne=new FileOutputStream(“tom.txt”);
outTwo=new ObjectOutputStream(outOne);
outTwo.writeObject(text);
outTwo.close();
outOne.close();
}
catch(IOException event){}
}
else if(e.getSource()==读入)
{ try{ inOne=new FileInputStream(“tom.txt”);
inTwo=new ObjectInputStream(inOne);
TextArea temp=(TextArea)inTwo.readObject();
temp.setBackground(Color.pink);
this.add(temp);
this.validate();
inTwo.close();
inOne.close();
}
catch(Exception event)
{ System.out.println(event);
}
}
}
}
class Boy implements TextListener,Serializable
{ TextArea text;
int i=10;
Boy(TextArea text)
{ this.text=text;
}
public void textValueChanged(TextEvent e)
{ i++;
text.setBackground(new Color((i3)%255,(i7)%255,(i17)%255));
}
}
例子18
import java.io.;
import java.nio.;
import java.nio.channels.;
public class Example10_18
{ public static void main(String args[])
{ int b;
byte tom[]=new byte[100];
try{
RandomAccessFile input=new RandomAccessFile(“Example10_17.java”,“rw”);
FileChannel channel=input.getChannel();
while((b=input.read(tom,0,10))!=-1)
{ FileLock lock=channel.tryLock();
String s=new String (tom,0,b);
System.out.println(s);
try { Thread.sleep(1000);
lock.release();
}
catch(Exception eee){System.out.println(eee);}
}
input.close();
}
catch(Exception ee)
{ System.out.println(ee);
}
}
}
例子19
import java.awt.;
import java.io.;
import java.awt.event.;
public class Example10_19
{ public static void main(String args[])
{ JDK f=new JDK();
}
}
class JDK extends Frame
implements ActionListener,Runnable
{ Thread compiler=null;
Thread run_prom=null;
boolean bn=true;
CardLayout mycard;
Panel p=new Panel();
File file_saved=null;
TextArea input_text=new TextArea(),//程序输入区
compiler_text=new TextArea(), //编译出错显示区
dos_out_text=new TextArea(); //显示System.out流输出的信息
Button button_input_text,button_compiler_text,
button_compiler,button_run_prom,button_see_doswin;
TextField input_flie_name_text=new TextField(“输入被编译的文件名字.java”);
TextField run_file_name_text=new TextField(“输入应用程序主类的名字”);
JDK()
{ super(“Java编程小软件”);
mycard=new CardLayout();
compiler=new Thread(this);
run_prom=new Thread(this);
button_input_text=new Button(“程序输入区”);
button_compiler_text=new Button(“编译结果区”);
button_compiler=new Button(“编译程序”);
button_run_prom=new Button(“运行应用程序”);
button_see_doswin=new Button(“查看System.out流输出的信息”);
p.setLayout(mycard);
p.add(“input”,input_text);
p.add(“compiler”,compiler_text);
p.add(“dos”,dos_out_text);
add(p,“Center”);
add( button_see_doswin,“South”);
compiler_text.setBackground(Color.pink);
Panel p1=new Panel();
p1.setLayout(new GridLayout(4,2));
p1.add(new Label(“输入程序：”));
p1.add(button_input_text);
p1.add(new Label(“编译结果：”));
p1.add(button_compiler_text);
p1.add(input_flie_name_text);
p1.add(button_compiler);
p1.add(run_file_name_text);
p1.add(button_run_prom);
add(p1,BorderLayout.NORTH);
button_input_text.addActionListener(this);
button_compiler_text.addActionListener(this);
button_compiler.addActionListener(this);
button_run_prom.addActionListener(this);
button_see_doswin.addActionListener(this);
addWindowListener(new WindowAdapter()
{public void windowClosing(WindowEvent e)
{ System.exit(0);
}
});
setBounds(100,120,700,360);
setVisible(true);
validate();
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()==button_input_text)
{ mycard.show(p,“input”);
}
else if(e.getSource()==button_compiler_text)
{ mycard.show(p,“compiler”);
}
else if(e.getSource()==button_see_doswin)
{ mycard.show(p,“dos”);
}
else if(e.getSource()==button_compiler)
{ if(!(compiler.isAlive()))
{ compiler=new Thread(this);
}
try{ compiler.start();
}
catch(Exception eee){}
mycard.show(p,“compiler”);
}
else if(e.getSource()==button_run_prom)
{ if(!(run_prom.isAlive()))
{ run_prom =new Thread(this);
}
try{ run_prom.start();
}
catch(Exception eee){}
mycard.show(p,“dos”);
}
}
public void run()
{ if(Thread.currentThread()==compiler)
{ compiler_text.setText(null);
String temp=input_text.getText().trim();
byte buffer[]=temp.getBytes();
int b=buffer.length;
String flie_name=input_flie_name_text.getText().trim();
try{ file_saved=new File(flie_name);
FileOutputStream writefile=new FileOutputStream(file_saved);
writefile.write(buffer,0,b);
writefile.close();
}
catch(IOException e5)
{ System.out.println("Error ");
}
try{ Runtime ce=Runtime.getRuntime();
InputStream in=ce.exec("javac "+flie_name).getErrorStream();
BufferedInputStream bin=new BufferedInputStream(in);
byte shuzu[]=new byte[100];
int n;boolean bn=true;
while((n=bin.read(shuzu,0,100))!=-1)
{ String s=null;
s=new String(shuzu,0,n);
compiler_text.append(s);
if(s!=null) bn=false;
}
if(bn)
{ compiler_text.append(“编译正确”);
}
}
catch(IOException e1){}
}
else if(Thread.currentThread()==run_prom)
{ dos_out_text.setText(null);
try{ Runtime ce=Runtime.getRuntime();
String path=run_file_name_text.getText().trim();
InputStream in=ce.exec("java "+path).getInputStream();
BufferedInputStream bin=new BufferedInputStream(in);
byte zu[]=new byte[150];
int m;String s=null;
while((m=bin.read(zu,0,150))!=-1)
{ s=new String(zu,0,m);
dos_out_text.append(s);
}
}
catch(IOException e1){}
}
}
}
例子20
import javax.swing.;
import java.io.;
public class Example10_20
{ public static void main(String args[])
{ byte b[]=new byte[30];
try{ FileInputStream input=new FileInputStream(“Example10_20.java”);
ProgressMonitorInputStream in=
new ProgressMonitorInputStream(null,“读取java文件”,input);
ProgressMonitor p=in.getProgressMonitor(); //获得进度条
while(in.read(b)!=-1)
{ String s=new String(b);
System.out.print(s);
Thread.sleep(1000);//由于文件较小，为了看清进度条这里有意延缓1秒
}
}
catch(Exception e){}
}
}

第十一章Java网络的基本知识
例子1
import java.awt.;
import java.awt.event.;
import java.net.;
import java.io.;
public class Example11_1
{ public static void main(String args[])
{ new NetWin();
}
}
class NetWin extends Frame
implements ActionListener,Runnable
{ Button button;
URL url;
TextField text;
TextArea area;
byte b[]=new byte[118];
Thread thread;
NetWin()
{ text=new TextField(20);
area=new TextArea(12,12);
button=new Button(“确定”);
button.addActionListener(this);
thread=new Thread(this);
Panel p=new Panel();
p.add(new Label(“输入网址:”));
p.add(text);
p.add(button);
add(area,BorderLayout.CENTER);
add(p,BorderLayout.NORTH);
setBounds(60,60,360,300);
setVisible(true);
validate();
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ System.exit(0);
}
});
}
public void actionPerformed(ActionEvent e)
{
if(!(thread.isAlive()))
thread=new Thread(this);
try{
thread.start();
}
catch(Exception ee)
{ text.setText(“我正在读取”+url);
}
}
public void run()
{ try { int n=-1;
area.setText(null);
url=new URL(text.getText().trim());
InputStream in=url.openStream();
while((n=in.read(b))!=-1)
{ String s=new String(b,0,n);
area.append(s);
}
}
catch(MalformedURLException e1)
{ text.setText(""+e1);
return;
}
catch(IOException e1)
{ text.setText(""+e1);
return;
}
}
}
例子2
import java.awt.;
import java.awt.event.;
import java.net.;
import java.io.;
import javax.swing.JEditorPane;
public class Example11_2
{ public static void main(String args[])
{ new Win();
}
}
class Win extends Frame
implements ActionListener,Runnable
{ Button button;
URL url;
TextField text;
JEditorPane editPane;
byte b[]=new byte[118];
Thread thread;
public Win()
{ text=new TextField(20);
editPane=new JEditorPane();
editPane.setEditable(false);
button=new Button(“确定”);
button.addActionListener(this);
thread=new Thread(this);
Panel p=new Panel();
p.add(new Label(“输入网址:”));
p.add(text);
p.add(button);
ScrollPane scroll=new ScrollPane();
scroll.add(editPane);
add(scroll,BorderLayout.CENTER);
add(p,BorderLayout.NORTH);
setBounds(160,60,360,300);
setVisible(true);
validate();
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ System.exit(0);
}
});
}
public void actionPerformed(ActionEvent e)
{ if(!(thread.isAlive()))
thread=new Thread(this);
try{ thread.start();
}
catch(Exception ee)
{ text.setText(“我正在读取”+url);
}
}
public void run()
{ try { int n=-1;
editPane.setText(null);
url=new URL(text.getText().trim());
editPane.setPage(url);
}
catch(Exception e1)
{ text.setText(""+e1);
return;
}
}
}
例子3
import java.awt.;
import java.awt.event.;
import java.net.;
import java.io.;
import javax.swing.event.;
import javax.swing.;
public class Example11_3
{ public static void main(String args[])
{ new LinkWin();
}
}
class LinkWin extends JFrame implements ActionListener,Runnable
{ Button button;
URL url;
TextField text;
JEditorPane editPane;
byte b[]=new byte[118];
Thread thread;
public LinkWin()
{ text=new TextField(20);
editPane=new JEditorPane();
editPane.setEditable(false);
button=new Button(“确定”);
button.addActionListener(this);
thread=new Thread(this);
Panel p=new Panel();
p.add(new Label(“输入网址:”));
p.add(text);
p.add(button);
ScrollPane scroll=new ScrollPane();
scroll.add(editPane);
add(scroll,BorderLayout.CENTER);
add(p,BorderLayout.NORTH);
setBounds(60,60,360,300);
setVisible(true);
validate();
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
editPane.addHyperlinkListener(new HyperlinkListener()
{
public void hyperlinkUpdate(HyperlinkEvent e)
{ if(e.getEventType()==
HyperlinkEvent.EventType.ACTIVATED)
{
try{ editPane.setPage(e.getURL());
}
catch(IOException e1)
{ editPane.setText(""+e1);
}
}
}});
}
public void actionPerformed(ActionEvent e)
{ if(!(thread.isAlive()))
thread=new Thread(this);
try{ thread.start();
}
catch(Exception ee)
{ text.setText(“我正在读取”+url);
}
}
public void run()
{ try {
int n=-1;
editPane.setText(null);
url=new URL(text.getText().trim());
editPane.setPage(url);
}
catch(Exception e1)
{ text.setText(""+e1);
return;
}
}
}

例子4
import java.net.;
public class DomainName
{ public static void main(String args[])
{ try{ InetAddress address_1=InetAddress.getByName(“www.sina.com.cn”);
System.out.println(address_1.toString());
InetAddress address_2=InetAddress.getByName(“166.111.222.3”);
System.out.println(address_2.toString());
}
catch(UnknownHostException e)
{ System.out.println(“无法找到 www.sina.com.cn”);
}
}
}
例子5
（1）客户端程序：
import java.io.;
import java.net.;
public class Client
{ public static void main(String args[])
{ String s=null;
Socket mysocket;
DataInputStream in=null;
DataOutputStream out=null;
try{
mysocket=new Socket(“127.0.0.1”,4331);
in=new DataInputStream(mysocket.getInputStream());
out=new DataOutputStream(mysocket.getOutputStream());
for(int k=1;k<100;k=k+2)
{ out.writeUTF(""+k);
s=in.readUTF();//in读取服务器发来的信息，堵塞状态
System.out.println(“客户收到:”+s);
Thread.sleep(500);
}
}
catch(Exception e)
{ System.out.println(“服务器已断开”+e);
}
}
}
（2）服务器端程序：
import java.io.;
import java.net.;
public class Server
{ public static void main(String args[])
{ ServerSocket server=null;
Socket you=null;
String s=null;
DataOutputStream out=null;
DataInputStream in=null;
try{ server=new ServerSocket(4331);
}
catch(IOException e1)
{System.out.println(e1);
}
try{ System.out.println(“等待客户呼叫”);
you=server.accept(); //堵塞状态，除非有客户呼叫
out=new DataOutputStream(you.getOutputStream());
in=new DataInputStream(you.getInputStream());
while(true)
{ s=in.readUTF(); // in读取客户放入"线路"里的信息，堵塞状态
int m=Integer.parseInt(s);
out.writeUTF(“你好:我是服务器”);
out.writeUTF(“你说的数是乘2后是:”+2m);
System.out.println(“服务器收到:”+s);
Thread.sleep(500);
}
}
catch(Exception e)
{ System.out.println(“客户已断开”+e);
}
}
}
例子6
(1) 客户端
import java.net.;
import java.io.;
import java.awt.;
import java.awt.event.;
import javax.swing.;
public class Client
{ public static void main(String args[])
{ new ComputerClient();
}
}
class ComputerClient extends Frame implements Runnable,ActionListener
{ Button connection,send;
TextField inputText,showResult;
Socket socket=null;
DataInputStream in=null;
DataOutputStream out=null;
Thread thread;
ComputerClient()
{ socket=new Socket();
setLayout(new FlowLayout());
Box box=Box.createVerticalBox();
connection=new Button(“连接服务器”);
send=new Button(“发送”);
send.setEnabled(false);
inputText=new TextField(12);
showResult=new TextField(12);
box.add(connection);
box.add(new Label(“输入三角形三边的长度,用逗号或空格分隔:”));
box.add(inputText);
box.add(send);
box.add(new Label(“收到的结果：”));
box.add(showResult);
connection.addActionListener(this);
send.addActionListener(this);
thread=new Thread(this);
add(box);
setBounds(10,30,300,400);
setVisible(true);
validate();
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ System.exit(0);
}
});
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()==connection)
{ try //请求和服务器建立套接字连接：
{ if(socket.isConnected())
{}
else
{ InetAddress address=InetAddress.getByName(“127.0.0.1”);
InetSocketAddress socketAddress=new InetSocketAddress(address,4331);
socket.connect(socketAddress);
in =new DataInputStream(socket.getInputStream());
out = new DataOutputStream(socket.getOutputStream());
send.setEnabled(true);
thread.start();
}
}
catch (IOException ee){}
}
if(e.getSource()==send)
{ String s=inputText.getText();
if(s!=null)
{ try { out.writeUTF(s);
}
catch(IOException e1){}
}
}
}
public void run()
{ String s=null;
while(true)
{ try{ s=in.readUTF();
showResult.setText(s);
}
catch(IOException e)
{ showResult.setText(“与服务器已断开”);
break;
}
}
}
}
（2）服务器端
import java.io.;
import java.net.;
import java.util.;
public class Server
{ public static void main(String args[])
{ ServerSocket server=null;
Server_thread thread;
Socket you=null;
while(true)
{ try{ server=new ServerSocket(4331);
}
catch(IOException e1)
{ System.out.println(“正在监听”); //ServerSocket对象不能重复创建
}
try{ System.out.println(" 等待客户呼叫");
you=server.accept();
System.out.println(“客户的地址:”+you.getInetAddress());
}
catch (IOException e)
{ System.out.println(“正在等待客户”);
}
if(you!=null)
{ new Server_thread(you).start(); //为每个客户启动一个专门的线程
}
}
}
}
class Server_thread extends Thread
{ Socket socket;
DataOutputStream out=null;
DataInputStream in=null;
String s=null;
boolean quesion=false;
Server_thread(Socket t)
{ socket=t;
try { out=new DataOutputStream(socket.getOutputStream());
in=new DataInputStream(socket.getInputStream());
}
catch (IOException e)
{}
}
public void run()
{ while(true)
{ double a[]=new double[3] ;
int i=0;
try{ s=in.readUTF();//堵塞状态，除非读取到信息
quesion=false;
StringTokenizer fenxi=new StringTokenizer(s," ,");
while(fenxi.hasMoreTokens())
{ String temp=fenxi.nextToken();
try{ a[i]=Double.valueOf(temp).doubleValue();i++;
}
catch(NumberFormatException e)
{ out.writeUTF(“请输入数字字符”);
quesion=true;
}
}
if(quesionfalse)
{ double p=(a[0]+a[1]+a[2])/2.0;
out.writeUTF(" “+Math.sqrt(p*(p-a[0])(p-a[1])(p-a[2])));
}
}
catch (IOException e)
{ System.out.println(“客户离开”);
return;
}
}
}
}
例子7
（1）服务器
Server.java
import java.io.;
import java.net.;
import java.util.zip.;
public class Server
{ public static void main(String args[])
{ ServerSocket server=null;
ServerThread thread;
Socket you=null;
while(true)
{ try{ server=new ServerSocket(4331);
}
catch(IOException e1)
{ System.out.println(“正在监听”);
}
try{ you=server.accept();
System.out.println(“客户的地址:”+you.getInetAddress());
}
catch (IOException e)
{ System.out.println(“正在等待客户”);
}
if(you!=null)
{ new ServerThread(you).start();
}
}
}
}
class ServerThread extends Thread
{ Socket socket;
ZipOutputStream out;
String s=null;
ServerThread(Socket t)
{ socket=t;
try { out=new ZipOutputStream(socket.getOutputStream());
}
catch (IOException e){}
}
public void run()
{ try{out.putNextEntry(new ZipEntry(“Example.java”));
FileInputStream reader=new FileInputStream(“Example.java”);
byte b[]=new byte[1024];
int n=-1;
while((n=reader.read(b,0,1024))!=-1)
{ out.write(b,0,n); //发送压缩后的数据到客户端。
}
out.putNextEntry(new ZipEntry(“E.java”));
reader=new FileInputStream(“E.java”);
n=-1;
while((n=reader.read(b,0,1024))!=-1)
{ out.write(b,0,n); //发送压缩后的数据到客户端。
}
reader.close();
out.close();
}
catch (IOException e) {}
}
}
（2）客户端
Client.java
import java.net.;
import java.io.;
import java.awt.;
import java.awt.event.;
import java.util.zip.;
public class Client extends Frame implements Runnable,ActionListener
{ Button connection,getFile;
TextArea showResult;
Socket socket=null;
ZipInputStream in;
Thread thread;
public Client()
{ socket=new Socket();
connection=new Button(“连接服务器,获取文件内容”);
setLayout(new FlowLayout());
showResult=new TextArea(10,28);
add(connection);
add(showResult);
connection.addActionListener(this);
thread=new Thread(this);
setBounds(100,100,460,410);
setVisible(true);
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ System.exit(0);
}
});
}
public void run()
{ byte b[]=new byte[1024];
ZipEntry zipEntry=null;
while(true)
{ try{ while((zipEntry=in.getNextEntry())!=null)
{ showResult.append(”\n"+zipEntry.toString()+":\n");
int n=-1;
while((n=in.read(b,0,1024))!=-1)
{ String str=new String(b,0,n);
showResult.append(str);
}
}
}
catch(IOException e) { }
}
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()connection)
{ try { if(socket.isConnected())
{}
else
{ InetAddress address=InetAddress.getByName(“127.0.0.1”);
InetSocketAddress socketAddress=new InetSocketAddress(address,4331);
socket.connect(socketAddress);
in=new ZipInputStream(socket.getInputStream());
thread.start();
}
}
catch (IOException ee)
{ System.out.println(ee);
}
}
}
public static void main(String args[])
{ Client win=new Client();
}
}
例子8
主机1
import java.net.;import java.awt.; import java.awt.event.*;
class Shanghai_Frame extends Frame implements Runnable,ActionListener
{ TextField out_message=new TextField(“发送数据到北京：”);
TextArea in_message=new TextArea();
Button b=new Button(“发送数据包到北京”);
Shanghai_Frame()
{ super(“我是上海”);
setSize(200,200);setVisible(true);
b.addActionListener(this);
add(out_message,“South”);add(in_message,“Center”);add(b,“North”);
Thread thread=new Thread(this);
thread.start();//线程负责接收数据包
}
public void actionPerformed(ActionEvent event) //点击按扭发送数据包
{ byte buffer[]=out_message.getText().trim().getBytes();
try{ InetAddress address=InetAddress.getByName(“127.0.0.1”);
DatagramPacket data_pack=
new DatagramPacket(buffer,buffer.length, address,888);
DatagramSocket mail_data=new DatagramSocket();
in_message.append(“数据报目标主机地址:”+data_pack.getAddress()+"\n");
in_message.append(“数据报目标端口是:”+data_pack.getPort()+"\n");
in_message.append(“数据报长度:”+data_pack.getLength()+"\n");
mail_data.send(data_pack);
}
catch(Exception e){}
}
public void run() // //接收数据包
{ DatagramPacket pack=null;
DatagramSocket mail_data=null;
byte data[]=new byte[8192];
try{ pack=new DatagramPacket(data,data.length);
mail_data=new DatagramSocket(666);
}
catch(Exception e){}
while(true)
{ if(mail_datanull) break;
else
try{ mail_data.receive(pack);
int length=pack.getLength();
InetAddress adress=pack.getAddress();
int port=pack.getPort();
String message=new String(pack.getData(),0,length);
in_message.append(“收到数据长度：”+length+"\n");
in_message.append(“收到数据来自：”+adress+“端口：”+port+"\n");
in_message.append(“收到数据是：”+message+"\n");
}
catch(Exception e){}
}
}
}
public class Shanghai
{ public static void main(String args[])
{ Shanghai_Frame shanghai_win=new Shanghai_Frame();
shanghai_win.addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{System.exit(0);
}
});
shanghai_win.validate();
}
}
主机2
import java.net.;import java.awt.; import java.awt.event.*;
class Beijing_Frame extends Frame implements Runnable,ActionListener
{ TextField out_message=new TextField(“发送数据到上海：”);
TextArea in_message=new TextArea();
Button b=new Button(“发送数据包到上海”);
Beijing_Frame()
{ super(“我是北京”);
setSize(200,200);setVisible(true);
b.addActionListener(this);
add(out_message,“South”);add(in_message,“Center”);add(b,“North”);
Thread thread=new Thread(this);
thread.start();//线程负责接收数据包
}
public void actionPerformed(ActionEvent event)
{ byte buffer[]=out_message.getText().trim().getBytes();
try{ InetAddress address=InetAddress.getByName(“127.0.0.1”);
DatagramPacket data_pack=
new DatagramPacket(buffer,buffer.length, address,666);
DatagramSocket mail_data=new DatagramSocket();
in_message.append(“数据报目标主机地址:”+data_pack.getAddress()+"\n");
in_message.append(“数据报目标端口是:”+data_pack.getPort()+"\n");
in_message.append(“数据报长度:”+data_pack.getLength()+"\n");
mail_data.send(data_pack);
}
catch(Exception e){}
}
public void run()
{ DatagramSocket mail_data=null;
byte data[]=new byte[8192];
DatagramPacket pack=null;
try{
pack=new DatagramPacket(data,data.length);
mail_data=new DatagramSocket(888);
}
catch(Exception e){}
while(true)
{ if(mail_datanull) break;
else
try{ mail_data.receive(pack);
int length=pack.getLength();
InetAddress adress=pack.getAddress();
int port=pack.getPort();
String message=new String(pack.getData(),0,length);
in_message.append(“收到数据长度：”+length+"\n");
in_message.append(“收到数据来自：”+adress+“端口：”+port+"\n");
in_message.append(“收到数据是：”+message+"\n");
}
catch(Exception e){}
}
}
}
public class Beijing
{ public static void main(String args[])
{ Beijing_Frame beijing_win=new Beijing_Frame();
beijing_win.addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{System.exit(0);
}
});
beijing_win.validate();
}
}
例子9
（1）广播信息的主机
BroadCast.java
import java.net.;
public class BroadCast extends Thread
{ String s=“天气预报,最高温度32度,最低温度25度”;
int port=5858; //组播的端口
InetAddress group=null; //组播组的地址
MulticastSocket socket=null; //多点广播套接字
BroadCast()
{try
{
group=InetAddress.getByName(“239.255.8.0”); //设置广播组的地址为239.255.8.0
socket=new MulticastSocket(port); //多点广播套接字将在port端口广播
socket.setTimeToLive(1); //多点广播套接字发送数据报范围为本地网络
socket.joinGroup(group); //加入广播组,加入group后,socket发送的数据报
} //可以被加入到group中的成员接收到
catch(Exception e)
{ System.out.println("Error: "+ e);
}
}
public void run()
{ while(true)
{ try{ DatagramPacket packet=null; //待广播的数据包
byte data[]=s.getBytes();
packet=new DatagramPacket(data,data.length,group,port);
System.out.println(new String(data));
socket.send(packet); //广播数据包
sleep(2000);
}
catch(Exception e)
{ System.out.println("Error: "+ e);
}
}
}
public static void main(String args[])
{ new BroadCast().start();
}
}
（2）接收广播的主机
Receive.java
import java.net.;
import java.awt.;
import java.awt.event.;
public class Receive extends Frame implements Runnable,ActionListener
{ int port; //组播的端口.
InetAddress group=null; //组播组的地址.
MulticastSocket socket=null; //多点广播套接字.
Button 开始接收,停止接收;
TextArea 显示正在接收内容,显示已接收的内容;
Thread thread; //负责接收信息的线程.
boolean 停止=false;
public Receive()
{ super(“定时接收信息”);
thread=new Thread(this);
开始接收=new Button(“开始接收”);
停止接收=new Button(“停止接收”);
停止接收.addActionListener(this);
开始接收.addActionListener(this);
显示正在接收内容=new TextArea(10,10);
显示正在接收内容.setForeground(Color.blue);
显示已接收的内容=new TextArea(10,10);
Panel north=new Panel();
north.add(开始接收);
north.add(停止接收);
add(north,BorderLayout.NORTH);
Panel center=new Panel();
center.setLayout(new GridLayout(1,2));
center.add(显示正在接收内容);
center.add(显示已接收的内容);
add(center,BorderLayout.CENTER);
validate();
port=5858; //设置组播组的监听端口
try{
group=InetAddress.getByName(“239.255.8.0”); //设置广播组的地址为239.255.8.0
socket=new MulticastSocket(port); //多点广播套接字将在port端口广播
socket.joinGroup(group); //加入广播组,加入group后,socket发送的数据报
} //可以被加入到group中的成员接收到
catch(Exception e){}
setBounds(100,50,360,380);
setVisible(true);
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ System.exit(0);
}
});

}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()==开始接收)
{ 开始接收.setBackground(Color.blue);
停止接收.setBackground(Color.gray);
if(!(thread.isAlive()))
{ thread=new Thread(this);
}
try{ thread.start();
停止=false;
}
catch(Exception ee) {}
}
if(e.getSource()停止接收)
{ 开始接收.setBackground(Color.gray);
停止接收.setBackground(Color.blue);
停止=true;
}
}
public void run()
{ while(true)
{byte data[]=new byte[8192];
DatagramPacket packet=null;
packet=new DatagramPacket(data,data.length,group,port); //待接收的数据包。
try { socket.receive(packet);
String message=new String(packet.getData(),0,packet.getLength());
显示正在接收内容.setText(“正在接收的内容:\n”+message);
显示已接收的内容.append(message+"\n");
}
catch(Exception e) {}
if(停止true)
{ break;
}
}
}
public static void main(String args[])
{ new Receive();
}
}

第十二章Java Applet基础
例子1
import java.applet.;
import java.awt.;
public class Example12_1 extends Applet
{ Button button1,button2;
int sum;
public void init()
{ setBackground(Color.gray);
button1=new Button(“yes”);
button2=new Button(“No”);
add(button1);
add(button2);
}
public void start()
{ sum=0;
for(int i=1;i<=100;i++)
{ sum=sum+i;
}
}
public void stop() { }
public void paint(Graphics g)
{ g.setColor(Color.blue);
g.drawString(“程序设计方法”,20,60);
g.setColor(Color.red);
g.drawString(“sum=”+sum,20,100);
}
}
例子2
import java.awt.;
import java.applet.;
public class Example12_2 extends Applet
{ int x=0,y=0;
public void init()
{ String s1=getParameter(“girl”);//从html得到"girl"的值。
String s2=getParameter(“boy”);//从html得到"boy"的值。
x=Integer.parseInt(s1);
y=Integer.parseInt(s2);
}
public void paint(Graphics g)
{ g.drawString(“x=”+x+","+“y=”+y,90,120);
}
}
Boy.html




例子3
import java.applet.;
import java.awt.;
import java.awt.event.;
import java.net.;
public class Boy extends Applet implements ActionListener
{ Button button;
URL url;
TextField text;
public void init()
{ text=new TextField(18);
button=new Button(“确定”);
add(new Label(“输入网址:”));
add(text); add(button);
button.addActionListener(this);
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()==button)
{ try { url=new URL(text.getText().trim());
getAppletContext().showDocument(url);
}
catch(MalformedURLException g)
{ text.setText(“不正确的URL:"+url);
}
}
}
}
例子4
import java.applet.;
import java.awt.;
import java.net.;
import java.io.;
public class ReadFile extends Applet
{ TextArea text;
URL url;
public void init()
{ text=new TextArea(12,40);
add(text);
}
public void start()
{ try { url=new URL(getCodeBase(),“hello.txt”);
InputStream in=url.openStream(); //url返回输入流
int n=-1;
byte b[]=new byte[100];
while((n=in.read(b))!=-1)
{ String str=new String(b,0,n);
text.append(str);
}
}
catch(Exception ee) {}
}
}

例子5
import java.applet.;
import java.awt.;
import java.awt.event.;
public class CircleAndRect extends
Applet implements Runnable
{ Thread left ,right;
Graphics mypen;
int x,y;
public void init()
{ left=new Thread(this);
right=new Thread(this);
x=10;y=10;
mypen=getGraphics();
}
public void start()
{ try { left.start();
right.start();
}
catch(Exception e){}
}
public void run()
{ while(true)
{ if(Thread.currentThread()==left)
{ x=x+1;
if(x>240) x=10;
mypen.setColor(Color.blue);
mypen.clearRect(10,10,300,40);
mypen.drawRect(10+x,10,40,40);
try{ left.sleep(60);
}
catch(InterruptedException e){}
}
else if(Thread.currentThread()==right)
{ y=y+1;
if(y>240) y=10; mypen.setColor(Color.red);
mypen.clearRect(10,90,300,40);
mypen.drawOval(10+y,90,40,40);
try{ right.sleep(60);
}
catch(InterruptedException e){}
}
}
}
}
例子6
（1）客户端
import java.net.;
import java.io.;
import java.awt.;
import java.applet.;
public class Client extends Applet implements Runnable
{ TextField text;
Socket socket=null;
ObjectInputStream in=null;
ObjectOutputStream out=null;
Thread thread;
public void init()
{ thread=new Thread(this);
}
public void start()
{ try { thread.start();
socket=new Socket(this.getCodeBase().getHost(), 4331);
in=new ObjectInputStream(socket.getInputStream());
out=new ObjectOutputStream(socket.getOutputStream());
}
catch(Exception e){}
}
public void run()
{ String s=null;
while(true)
{ try{ text=(TextField)in.readObject();
add(text);
validate();
return;
}
catch(Exception e) {}
}
}
}
（2）服务器端
import java.io.;
import java.net.;
import java.util.;
import java.awt.*;
public class Server
{ public static void main(String args[])
{ ServerSocket server=null;
Server_thread thread;
Socket you=null;
while(true)
{ try{ server=new ServerSocket(4331);
}
catch(IOException e1)
{ System.out.println(“正在监听”);
}
try{ you=server.accept();
}
catch (IOException e){}
if(you!=null)
{ new Server_thread(you).start();
}
}
}
}
class Server_thread extends Thread
{ Socket socket;
ObjectOutputStream out=null;
ObjectInputStream in=null;
String s=null;
Server_thread(Socket t)
{ socket=t;
try { out=new ObjectOutputStream(socket.getOutputStream());
in=new ObjectInputStream(socket.getInputStream());
}
catch (IOException e){}
}
public void run()
{ TextField text=new TextField(“你好，我是服务器”,20);
try{ out.writeObject(text);
}
catch (IOException e){}
}
}

第十三章常见数据结构的Java实现
例子1
import java.util.;
public class Example13_1
{ public static void main(String args[])
{ List list=new LinkedList();
list.add(“is”);
list.add(“a”);
int number=list.size();
System.out.println(“现在链表中有”+number+
“个节点:”);
for(int i=0;i<number;i++)
{ String temp=(String)list.get(i);
System.out.println(“第”+i+“节点中的数据:”+temp);
}
list.add(0,“It”);
number=list.size();
list.add(number-1,“door”);
number=list.size();
System.out.println(“现在链表中有”+number+“个节点:”);
for(int i=0;i<number;i++)
{ String temp=(String)list.get(i);
System.out.println(“第”+i+“节点中的数据:”+temp);
}
list.remove(0);
list.remove(1);
list.set(0,“open”);
number=list.size();
System.out.println(“现在链表中有”+number+“个节点:”);
for(int i=0;i<number;i++)
{ String temp=(String)list.get(i);
System.out.println(“第”+i+“节点中的数据:”+temp);
}
}
}
例子2
import java.util.;
class Student
{ String name ;
int number;
Student(String name,int number)
{ this.name=name;
this.number=number;
}
}
public class Example13_2
{ public static void main(String args[])
{ List list=new LinkedList();
for(int k=1;k<=22222;k++)
{ list.add(new Student(“I am “+k,k));
}
Iterator iter=list.iterator();
long time1=System.currentTimeMillis();
while(iter.hasNext())
{ Student te=(Student)iter.next();
}
long time2=System.currentTimeMillis();
System.out.println(“遍历链表用时:”+(time2-time1)+“毫秒”);
time1=System.currentTimeMillis();
for(int i=0;i<list.size();i++)
{ Student te=(Student)list.get(i);
}
time2=System.currentTimeMillis();
System.out.println(“遍历链表用时:”+(time2-time1)+“毫秒”);
}
}
例子3
import java.util.;
import java.awt.event.;
import java.awt.;
import javax.swing.;
import java.io.;
public class Example13_3
{ public static void main(String args[])
{ ShowWin win=new ShowWin();
win.setSize(320,200);
win.setVisible(true);
}
}
class 商品 implements Serializable
{ String name,price;
商品(String name,String price)
{ this.name=name;
this.price=price;
}
}
class ShowWin extends Frame implements ActionListener
{ LinkedList goods_list=null;
File file=new File(“商品信息.dat”) ;
TextField 名称文本框=new TextField(),
单价文本框=new TextField(),
删除文本框=new TextField();
Button b_add=new Button(“添加商品”),
b_del=new Button(“删除商品”);
TextArea 显示区=new TextArea(7,25);
ShowWin()
{ setLayout(new GridLayout(1,2));
goods_list=new LinkedList();
Box boxV1=Box.createVerticalBox();
boxV1.add(new Label(“输入名称:”));
boxV1.add(new Label(“输入单价:”));
boxV1.add(new Label(“点击添加:”));
boxV1.add(new Label(“删除的名称:”));
boxV1.add(new Label(“点击删除:”));
Box boxV2=Box.createVerticalBox();
boxV2.add(名称文本框);
boxV2.add(单价文本框);
boxV2.add(b_add);
boxV2.add(删除文本框);
boxV2.add(b_del);
Box baseBox=Box.createHorizontalBox();
baseBox.add(boxV1);
baseBox.add(boxV2);
Panel p=new Panel();
p.add(baseBox);
add§;
add(显示区);
b_add.addActionListener(this);
b_del.addActionListener(this);
addWindowListener(new WindowAdapter()
{public void windowClosing(WindowEvent e)
{System.exit(0);
}
});
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()==b_add)
{ String name,price;
name=名称文本框.getText();
price=单价文本框.getText();
if(file.exists())
{ if(name.length()>0&&price.length()>0)
{ 商品 goods=new 商品(name,price);
try { FileInputStream come_in=new FileInputStream(file);
ObjectInputStream in=new ObjectInputStream(come_in);
goods_list=(LinkedList)in.readObject();
in.close();
goods_list.add(goods);
FileOutputStream outOne=new FileOutputStream(file);
ObjectOutputStream out=new ObjectOutputStream(outOne);
out.writeObject(goods_list);
out.close();
}
catch(Exception event){}
}
else
{ 名称文本框.setText(“名称,价钱必须输入”);
}
}
else
{ if(name.length()>0&&price.length()>0)
{ 商品 goods=new 商品(name,price);
try { goods_list.add(goods);
FileOutputStream outOne=new FileOutputStream(file);
ObjectOutputStream out=new ObjectOutputStream(outOne);
out.writeObject(goods_list);
out.close();
}
catch(Exception event){}
}
else
{ 名称文本框.setText(“名称,价钱必须输入”);
}
}
showing();
}
else if(e.getSource()==b_del)
{ String name=删除文本框.getText();
try { FileInputStream come_in=new FileInputStream(file);
ObjectInputStream in=new ObjectInputStream(come_in);
goods_list=(LinkedList)in.readObject();
in.close();
for(int i=0;i<goods_list.size();i++)
{ 商品 temp=(商品)goods_list.get(i);
if(temp.name.equals(name))
goods_list.remove(i);
}
FileOutputStream outOne=new FileOutputStream(file);
ObjectOutputStream out=new ObjectOutputStream(outOne);
out.writeObject(goods_list);
out.close();
}
catch(Exception event){}
showing();
}
}
public void showing()
{ 显示区.setText(null);
try { FileInputStream come_in=new FileInputStream(file);
ObjectInputStream in=new ObjectInputStream(come_in);
goods_list=(LinkedList)in.readObject();
}
catch(Exception event){}
Iterator iter=goods_list.iterator();
while(iter.hasNext())
{ 商品 te=(商品)iter.next();
显示区.append(“名称:”+te.name+",");
显示区.append(“单价:”+te.price+".");
显示区.append("\n");
}
}
}
例子4
import java.util.;
public class Example13_4
{ public static void main(String args[])
{ Stack mystack=new Stack();
for(char c=‘A’;c<=‘Z’;c++)
{ mystack.push(new Character©);
}
while(!(mystack.empty()))
{ Character temp=(Character)mystack.pop();
System.out.print(“弹出数据:”+temp.charValue());
System.out.println(” 栈中还剩”+mystack.size()+“个数据”);
}
}
}
例子5
import java.util.;
public class Example13_5
{ public static void main(String args[])
{ Stack mystack=new Stack();
System.out.print(" “+1);
System.out.print(” “+1);
mystack.push(new Long(1));
mystack.push(new Long(1));
int k=1;
while(k<=50)
for(long i=1;i<=2;i++)
{ Long F1=(Long)mystack.pop();
Long F2=(Long)mystack.pop();
long f1=F1.longValue();
long f2=F2.longValue();
System.out.print(” "+(f1+f2));
Long temp=new Long(f1+f2);
mystack.push(temp);
mystack.push(F2);
k++;
}
}
}
例子6
import java.util.;
public class Example13_6
{ public static void main(String args[])
{ TreeSet mytree=new TreeSet();
mytree.add(“boy”);
mytree.add(“zoo”);
mytree.add(“apple”);
mytree.add(“girl”);
Iterator te=mytree.iterator();
while(te.hasNext())
System.out.println(""+te.next());
}
}
例子7
import java.util.;import java.awt.;
class Student implements Comparable
{ int english=0;
String name;
Student(int english,String name)
{ this.name=name;
this.english=english;
}
public int compareTo(Object b)
{ Student st=(Student)b;
return (this.english-st.english);
}
}
public class Example13_7
{ public static void main(String args[])
{ TreeSet mytree=new TreeSet(new Comparator()
{ public int compare(Object a,Object b)
{ Student stu1=(Student)a;
Student stu2=(Student)b;
return stu1.compareTo(stu2);
}
});
Student st1,st2,st3,st4;
st1=new Student(90,“赵一”);
st2=new Student(66,“钱二”);
st3=new Student(86,“孙三”);
st4=new Student(76,“李四”);
mytree.add(st1);
mytree.add(st2);
mytree.add(st3);
mytree.add(st4);
Iterator te=mytree.iterator();
while(te.hasNext())
{ Student stu=(Student)te.next();
System.out.println(""+stu.name+" “+stu.english);
}
}
}
例子8
import java.util.;
import java.awt.event.;
import java.awt.;
import java.io.;
public class Example13_8
{ public static void main(String args[])
{ Win win=new Win();
win.setSize(500,250);
win.setVisible(true);
win.addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{System.exit(0);
}
});
}
}
class 节目 implements Comparable,Serializable
{ String name;double time;
节目(String 名称,double 演出时间)
{ name=名称;
time=演出时间;
}
public int compareTo(Object b)
{ 节目 item=(节目)b;
return (int)((this.time-item.time)1000);
}
}
class Win extends Frame implements ActionListener
{ TreeSet 节目清单=null;
TextField 名称文本框=new TextField(10),
时间文本框=new TextField(5),
删除文本框=new TextField(5);
Button b_add=new Button(“添加节目”),
b_del=new Button(“删除节目”),
b_show =new Button(“显示节目清单”);
TextArea 显示区=new TextArea();
Win()
{ 节目清单=new TreeSet(new Comparator()
{ public int compare(Object a,Object b)
{ 节目 item_1=(节目)a;
节目 item_2=(节目)b;
return item_1.compareTo(item_2);
}
});
Panel 节目单输入区=new Panel();
节目单输入区.add(new Label(“节目名称:”));
节目单输入区.add(名称文本框);
节目单输入区.add(new Label(“演出时间:”));
节目单输入区.add(时间文本框);
节目单输入区.add(new Label(“点击添加:”));
节目单输入区.add(b_add);
节目单输入区.add(b_show);
Panel 节目单删除区=new Panel();
节目单删除区.add(new Label(“输入演出的时间:”));
节目单删除区.add(删除文本框);
节目单删除区.add(new Label(“点击删除:”));
节目单删除区.add(b_del);
Panel 节目单显示区=new Panel();
节目单显示区.add(显示区);
显示区.setBackground(Color.pink);
b_add.addActionListener(this);
b_del.addActionListener(this);
b_show.addActionListener(this);
add(节目单输入区,“North”);
add(节目单显示区,“Center”);
add(节目单删除区,“South”);
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()==b_add)
{ String 名称=null;
double 时间=0.0;
名称=名称文本框.getText();
try{ 时间=Double.parseDouble(时间文本框.getText());
}
catch(NumberFormatException ee)
{ 时间文本框.setText(“请输入代表时间的实数”);
}
节目 programme=new 节目(名称,时间);
节目清单.add(programme);
showing();
}
else if(e.getSource()==b_del)
{ 节目 待删除节目=null;
double time=Double.valueOf(删除文本框.getText()).doubleValue();
Iterator te=节目清单.iterator();
while(te.hasNext())
{ 节目 item=(节目)te.next();
if(Math.abs(item.time-time)<=0.000001d)
{ 待删除节目=item;
}
}
if(待删除节目!=null)
节目清单.remove(待删除节目);
showing();
}
else if(e.getSource()==b_show)
{ showing();
}
}
void showing()
{ 显示区.setText(null);
Iterator iter=节目清单.iterator();
while(iter.hasNext())
{ 节目 item=(节目)iter.next();
显示区.append(“节目名称:”+item.name+“演出时间: “+item.time);
显示区.append(”\n”);
}
}
}
例子9
import java.util.;
class StudentKey implements Comparable
{ double d=0;
StudentKey (double d)
{ this.d=d;
}
public int compareTo(Object b)
{ StudentKey st=(StudentKey)b;
if((this.d-st.d)==0)
{ return -1;
}
else
{ return (int)((this.d-st.d)1000);
}
}
}
class Student
{ String name=null;
double math,english;
Student(String s,double m,double e)
{ name=s;
math=m;
english=e;
}
}
public class Example13_9
{ public static void main(String args[ ])
{ TreeMap treemap= new TreeMap(new Comparator()
{ public int compare(Object a,Object b)
{ StudentKey key1=(StudentKey)a;
StudentKey key2=(StudentKey)b;
return key1.compareTo(key2);
}
});
String str[]={“赵一”,“钱二”,“孙三”,“李四”};
double math[]={89,45,78,76};
double english[]={67,66,90,56};
Student student[]=new Student[4];
for(int k=0;k<student.length;k++)
{ student[k]=new Student(str[k],math[k],english[k]);
}
StudentKey key[]=new StudentKey[4] ;
for(int k=0;k<key.length;k++)
{ key[k]=new StudentKey(student[k].math);
}
for(int k=0;k<student.length;k++)
{ treemap.put(key[k],student[k]);
}
int number=treemap.size();
System.out.println(“树映射中有”+number+“个对象,按数学成绩排序:”);
Collection collection=treemap.values();
Iterator iter=collection.iterator();
while(iter.hasNext())
{ Student stu=(Student)iter.next();
System.out.println("姓名 “+stu.name+” 数学 "+stu.math);
}
treemap.clear();
for(int k=0;k<key.length;k++)
{ key[k]=new StudentKey(student[k].english);
}
for(int k=0;k<student.length;k++)
{ treemap.put(key[k],student[k]);
}
number=treemap.size();
System.out.println(“树映射中有”+number+“个对象:按英语成绩排序:”);
collection=treemap.values();
iter=collection.iterator();
while(iter.hasNext())
{ Student stu=(Student)iter.next();
System.out.println("姓名 “+stu.name+” 英语 "+stu.english);
}
}
}
例子10
import java.util.;
public class Example13_10
{ public static void main(String args[])
{ Integer one=new Integer(1),
two=new Integer(2),
three=new Integer(3),
four=new Integer(4),
five=new Integer(5),
six=new Integer(6);
HashSet A=new HashSet(),
B=new HashSet(),
tempSet=new HashSet();
A.add(one);
A.add(two);
A.add(three);
A.add(four);
B.add(one);
B.add(two);
B.add(five);
B.add(six);
tempSet=(HashSet)A.clone();
A.removeAll(B); //A变成调用该方法之前的A集合与B集合的差集
B.removeAll(tempSet); //B变成调用该方法之前的B集合与tempSet集合的差集
B.addAll(A); //B就是最初的A与B的对称差
int number=B.size();
System.out.println(“A和B的对称差集合有”+number+“个元素:”);
Iterator iter=B.iterator();
while(iter.hasNext())
{ Integer te=(Integer)iter.next();
System.out.print(” “+te.intValue());
}
}
}
例子11
MainClass.java
public class MainClass
{ public static void main(String args[])
{ new ManagerWindow();
}
}
Student.java
public class Student
implements java.io.Serializable
{ String number,name;
public void setNumber(String number)
{ this.number=number;
}
public String getNumber()
{ return number;
}
public void setName(String name)
{ this.name=name;
}
public String getName()
{ return name;
}
}
ManagerWindow.java
import java.awt.;
import java.awt.event.;
import javax.swing.;
import java.io.;
import java.util.Hashtable;
public class ManagerWindow extends Frame implements ActionListener
{ InputStudent 基本信息录入=null;
Inquest 基本信息查询=null;
Button 查询;
Hashtable 基本信息=null;
File file=null;
public ManagerWindow()
{ 基本信息=new Hashtable();
查询=new Button(“查询”);
查询.addActionListener(this);
file=new File(“基本信息.txt”);
if(!file.exists())
{ try{ FileOutputStream out=new FileOutputStream(file);
ObjectOutputStream objectOut=new ObjectOutputStream(out);
objectOut.writeObject(基本信息);
objectOut.close();
out.close();
}
catch(IOException e){}
}
基本信息录入=new InputStudent(file);
基本信息查询=new Inquest(this,file);
add(基本信息录入,BorderLayout.CENTER);
add(查询,BorderLayout.SOUTH);
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ System.exit(0);
}
});
setVisible(true);
setBounds(100,50,420,380);
validate();
}
public void actionPerformed(ActionEvent e)
{ 基本信息查询.setVisible(true);
}
}
InputStudent.java
import java.awt.;
import java.awt.event.;
import javax.swing.;
import java.io.;
import java.util.;
public class InputStudent extends Panel implements ActionListener
{ Hashtable 基本信息表=null;
TextField 学号,姓名;
Student 学生=null;
Button 录入;
FileInputStream inOne=null;
ObjectInputStream inTwo=null;
FileOutputStream outOne=null;
ObjectOutputStream outTwo=null;
File file=null;
public InputStudent(File file)
{ this.file=file;
学号=new TextField(10);
姓名=new TextField(10);
录入=new Button(“录入”);
录入.addActionListener(this);
add(new Label(“学号:”,Label.CENTER));
add(学号);
add(new Label(“姓名:”,Label.CENTER));
add(姓名);
add(录入);
validate();
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()录入)
{ String number="";
number=学号.getText();
if(number.length()>0)
{ try { inOne=new FileInputStream(file);
inTwo=new ObjectInputStream(inOne);
基本信息表=(Hashtable)inTwo.readObject();
inOne.close();
inTwo.close();
}
catch(Exception ee){}
if(基本信息表.containsKey(number))
{ String m=“信息已存在,新的信息将覆盖原信息!”;
int ok=JOptionPane.showConfirmDialog(this,m,“确认”,
JOptionPane.YES_NO_OPTION,JOptionPane.INFORMATION_MESSAGE);
if(okJOptionPane.YES_OPTION)
{ record(number);
}
}
else
{ record(number);
}
}
else
{ String warning=“必须要输入学号!”;
JOptionPane.showMessageDialog(this,warning,“警告”,
JOptionPane.WARNING_MESSAGE);
}
}
}
public void record(String number)
{ String name=姓名.getText();
学生=new Student();
学生.setNumber(number);
学生.setName(name);
try{ outOne=new FileOutputStream(file);
outTwo=new ObjectOutputStream(outOne);
基本信息表.put(number,学生);
outTwo.writeObject(基本信息表);
outTwo.close();
outOne.close();
学号.setText(null);
姓名.setText(null);
}
catch(Exception ee){}
}
}
Inquest.java
import java.awt.;
import java.awt.event.;
import java.io.;
import java.util.;
import javax.swing.;
public class Inquest extends Dialog implements ActionListener
{ Hashtable 基本信息表=null;
TextField 学号;
Button 按学号查询,查询全部;
TextArea show=new TextArea(6,28);
FileInputStream inOne=null;
ObjectInputStream inTwo=null;
File file=null;
public Inquest(Frame f,File file)
{ super(f,“查询对话框”,false);
setLayout(new FlowLayout());
this.file=file;
学号=new TextField(10);
按学号查询=new Button(“按学号查询”);
按学号查询.addActionListener(this);
查询全部=new Button(“查询全部”);
查询全部.addActionListener(this);
add(new Label(“输入要查询的学号:”,JLabel.CENTER));
add(学号);
add(按学号查询);
add(查询全部);
add(show);
setBounds(100,200,360,270);
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ setVisible(false);
}
});
}
public void actionPerformed(ActionEvent e)
{ show.setText(null);
readHashtable();
if(e.getSource()==按学号查询)
{ String number=”";
number=学号.getText();
if(number.length()>0)
{ if(基本信息表.containsKey(number))
{ Student stu=(Student)基本信息表.get(number);
show.setText(“学号:”+stu.getNumber()+" 姓名:"+stu.getName());
}
else
{ String warning=“该学号不存在!”;
JOptionPane.showMessageDialog(this,warning,“警告”,
JOptionPane.WARNING_MESSAGE);
}
}
else
{ String warning=“必须要输入学号!”;
JOptionPane.showMessageDialog(this,warning,“警告”,
JOptionPane.WARNING_MESSAGE);
}
}
if(e.getSource()==查询全部)
{ Enumeration enum=基本信息表.elements();
while(enum.hasMoreElements()) //遍历当前散列表
{ Student stu=(Student)enum.nextElement();
show.append(“学号:”+stu.getNumber()+" 姓名:"+stu.getName()+"\n");
}
}
}
public void readHashtable()
{ try { inOne=new FileInputStream(file);
inTwo=new ObjectInputStream(inOne);
基本信息表=(Hashtable)inTwo.readObject();
inOne.close();
inTwo.close();
}
catch(Exception ee) {}
}
}
例子12
import java.util.Vector;
public class Example13_12
{ public static void main(String args[])
{ Vector vector=new Vector();
int a[]={1,2,3,4,1,2,3,4,1,2,3,4,1,2,3,4};
System.out.println(“随机排列之前的数组:”);
for(int i=0;i<a.length;i++)
{ System.out.print(" “+a[i]);
}
System.out.println(”");
for(int i=0;i<a.length;i++)
{ vector.add(new Integer(a[i]));
}
int k=0;
while(vector.size()>0)
{ int index=(int)(Math.random()*vector.size());
int number=((Integer)vector.get(index)).intValue();
a[k]=number;
k++;
vector.removeElementAt(index);
}
System.out.println(“随机排列之后的数组:”);
for(int i=0;i<a.length;i++)
{ System.out.print(" "+a[i]);
}
}
}

第十四章 图形与图像
例子1
import java.applet.;
import java.awt.;
public class Example14_1 extends Applet
{ public void paint(Graphics g)
{ g.drawOval(0,0,100,100);
g.drawRoundRect(110,10,90,60,50,30);
g.setColor(Color.black);
g.fillArc(0,0,100,100,-90,-180);
g.setColor(Color.white);
g.fillArc(0,0,100,100, -90,180);
g.fillArc(25,0,50,50,-90,-180);
g.setColor(Color.black);
g.fillOval(40,15,20,20);
g.fillArc(25,50,50,50,90,-180);
g.setColor(Color.white);
g.fillOval(40,65,20,20);
g.setColor(Color.black);
int px[]={50,70,170};
int py[]={120,150,80};
g.drawPolygon(px,py,3);
}
}
例子2
import java.applet.;
import java.awt.;
public class Example14_2 extends Applet
{ Font f1=new Font(“隶书”,Font.BOLD,28);
Font f2= new Font(“TimesRoman”,Font.BOLD+Font.ITALIC,16);
public void paint(Graphics g)
{ g.setFont(f1);
g.drawString(“计算机科学技术”,10,30);
g.setFont(f2);
char a[]=“I Love You”.toCharArray();
int x=80,y=0;
for(int i=0;i<a.length;i++)
{ y=x-15;
g.drawChars(a,i,1,x,y);
x=x+8;
}
}
}
例子3
import java.applet.;
import java.awt.;
import java.awt.event.;
public class Example14_3 extends Applet
{ int i=0;
public void paint(Graphics g)
{ i=(i+2)%360;
Color c=new Color((3i)%255,(7i)%255,(11i)%255);
g.setColor©;
g.fillArc(30,50,120,100,i,2);
g.fillArc(30,152,120,100,i,2);
try{ Thread.sleep(300);
}
catch(InterruptedException e){}
repaint();
}
public void update(Graphics g)
{ g.clearRect(30,152,120,100);
paint(g);
}
}
例子4
import java.awt.;
import java.applet.;
import java.awt.geom.;
public class Example14_4 extends Applet
{ public void paint(Graphics g)
{ g.setColor(Color.blue) ;
Graphics2D g_2d=(Graphics2D)g;
Ellipse2D ellipse=
new Ellipse2D.Double (20,30,100,50);
Line2D line=new Line2D.Double(70,30,70,10);
g_2d.setColor(Color.red);
g_2d.draw(line);
for(int i=1,k=0;i<=6;i++)
{ ellipse.setFrame(20+k,30,100-2k,50);
if(i<=5)
g_2d.draw(ellipse);
else
g_2d.fill(ellipse);
k=k+5;
}
}
}
例子5
import java.awt.;
import java.applet.;
import java.awt.geom.;
public class Example14_4 extends Applet
{ public void paint(Graphics g)
{ g.setColor(Color.red) ;
Graphics2D g_2d=(Graphics2D)g;
Arc2D arc=
new Arc2D.Double (2,2,80,80,0,270,Arc2D.OPEN);
g_2d.draw(arc);
arc.setArc(2,90,80,80,0,270,Arc2D.CHORD);
g_2d.draw(arc);
arc.setArc(90,2,80,80,0,270,Arc2D.PIE);
g_2d.fill(arc);
}
}
例子6
import java.awt.;
import java.applet.;
import java.awt.geom.;
public class Example14_6 extends Applet
{ public void paint(Graphics g)
{ Graphics2D g_2d=(Graphics2D)g;
QuadCurve2D quadCurve=
new QuadCurve2D.Double(2,10,51,70,100,10);
g_2d.drawString(“控制点”,51,70);
Line2D line=new Line2D.Double(2,10,51,70);
g_2d.draw(quadCurve);
g_2d.draw(line);
line.setLine(100,10,51,70);
g_2d.draw(line);
CubicCurve2D cubicCurve=
new CubicCurve2D.Double(2,96,40,180,70,50,136,96);
g_2d.draw(cubicCurve);
}
}
例子7
import java.awt.;
import java.applet.;
import java.awt.geom.*;
public class Example14_7 extends Applet
{
public void paint(Graphics g)
{
Graphics2D g_2d=(Graphics2D)g;
BasicStroke bs_1
=new BasicStroke(16,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
BasicStroke bs_2
=new BasicStroke(16f,BasicStroke.CAP_ROUND,BasicStroke.JOIN_MITER);
BasicStroke bs_3
=new BasicStroke(16f,BasicStroke.CAP_SQUARE,BasicStroke.JOIN_ROUND);
Line2D redLineOne=new Line2D.Double(0,16,120,16);
Line2D redLineTwo=new Line2D.Double(120,16,120,70);
g_2d.setStroke(bs_1);
g_2d.setColor(Color.red);
g_2d.draw(redLineOne);
g_2d.draw(redLineTwo);
g_2d.setColor(Color.blue);
Line2D blueLineOne=new Line2D.Double(0,40,85,40);
Line2D blueLineTwo=new Line2D.Double(85,40,85,80);
g_2d.setStroke(bs_2);
g_2d.draw(blueLineOne);
g_2d.draw(blueLineTwo);
g_2d.setColor(Color.green);
Line2D greanLineOne=new Line2D.Double(0,80,65,80);
Line2D greanLineTwo=new Line2D.Double(65,80,65,120);
g_2d.setStroke(bs_3);
g_2d.draw(greanLineOne);
g_2d.draw(greanLineTwo);

}

}
例子8
import java.awt.;
import java.applet.;
import java.awt.geom.;
public class Example extends Applet
{ public void paint(Graphics g)
{ Graphics2D g_2d=(Graphics2D)g;
GradientPaint gradient_1
=new GradientPaint(0,0,Color.red,50,50,Color.green,false);
g_2d.setPaint(gradient_1);
Rectangle2D rect_1=new Rectangle2D.Double (0,0,50,50);
g_2d.fill(rect_1);
GradientPaint gradient_2
=new GradientPaint(60,50,Color.white,150,50,Color.red,false);
g_2d.setPaint(gradient_2);
Rectangle2D rect_2=new Rectangle2D.Double (60,50,90,50);
g_2d.fill(rect_2);
}
}
例子9
import java.awt.;
import java.applet.;
import java.awt.geom.;
public class Example14_9 extends Applet
{ public void paint(Graphics g)
{ Graphics2D g_2d=(Graphics2D)g;
String s=“旋转起来”;
Ellipse2D ellipse=
new Ellipse2D. Double (30,30,80,30);
AffineTransform trans=new AffineTransform();
for(int i=1;i<=24;i++)
{ trans.rotate(15.0Math.PI/180,70,45);
g_2d.setTransform(trans);
//现在画的就是旋转后的椭圆样子
g_2d.draw(ellipse);
}
for(int i=1;i<=12;i++)
{ trans.rotate(30.0Math.PI/180,60,160);
g_2d.setTransform(trans);
//现在画的就是旋转后的字符串
g_2d.drawString(s,60,160);
}
}
}
例子10
import java.awt.geom.;
import java.awt.;
import java.applet.;
public class Example14_8 extends Applet
{ public void paint(Graphics g)
{ Graphics2D g_2d=(Graphics2D)g;
Ellipse2D ellipse=
new Ellipse2D.Double(0,2,80,80);
Rectangle2D rect=
new Rectangle2D.Double(40,2,80,80);
Area a1=new Area(ellipse);
Area a2=new Area(rect);
a1.intersect(a2); //“与”
g_2d.fill(a1);
ellipse.setFrame(130,2,80,80);
rect.setFrame(170,2,80,80);
a1=new Area(ellipse);
a2=new Area(rect);
a1.add(a2); //“或”
g_2d.draw(a1);
ellipse.setFrame(0,90,80,80);
rect.setFrame(40,90,80,80);
a1=new Area(ellipse);
a2=new Area(rect);
a1.subtract(a2); //“差”
g_2d.draw(a1);
ellipse.setFrame(130,90,80,80);
rect.setFrame(170,90,80,80);
a1=new Area(ellipse);
a2=new Area(rect);
a1.exclusiveOr(a2); //“异或”
g_2d.fill(a1);
}
}
例子11
import java.awt.;
import java.applet.;
import java.awt.geom.;
public class Example14_11 extends Applet
{
public void paint(Graphics g)
{
Graphics2D g_2d=(Graphics2D)g;
Ellipse2D ellipse1=
new Ellipse2D. Double (20,80,60,60),
ellipse2=
new Ellipse2D. Double (40,80,80,80);
g_2d.setColor(Color.blue);
Area a1=new Area(ellipse1),
a2=new Area(ellipse2);
a1.subtract(a2); //“差”
AffineTransform trans=new AffineTransform();
for(int i=1;i<=10;i++)
{
trans.rotate(36.0Math.PI/180,95,105);
g_2d.setTransform(trans);
g_2d.fill(a1);
}
}
}
例子12
import java.awt.;
import java.awt.event.;
import javax.swing.Timer;
import java.awt.geom.;
import java.util.;
class Clock extends Canvas
implements ActionListener
{ Date date;
Timer secondTime;
int hour,munite,second;
Line2D secondLine,muniteLine,hourLine;
int a,b,c;
double pointSX[]=new double[60],//用来表示秒针端点坐标的数组
pointSY[]=new double[60],
pointMX[]=new double[60], //用来表示分针端点坐标的数组
pointMY[]=new double[60],
pointHX[]=new double[60], //用来表示时针端点坐标的数组
pointHY[]=new double[60];
Clock()
{ secondTime=new Timer(1000,this);
pointSX[0]=0; //12点秒针位置
pointSY[0]=-100;
pointMX[0]=0; //12点分针位置
pointMY[0]=-90;
pointHX[0]=0; //12点时针位置
pointHY[0]=-70;
double angle=6Math.PI/180; //刻度为6度
for(int i=0;i<59;i++) //计算出各个数组中的坐标
{ pointSX[i+1]=pointSX[i]Math.cos(angle)-Math.sin(angle)pointSY[i];
pointSY[i+1]=pointSY[i]Math.cos(angle)+pointSX[i]Math.sin(angle);
pointMX[i+1]=pointMX[i]Math.cos(angle)-Math.sin(angle)pointMY[i];
pointMY[i+1]=pointMY[i]Math.cos(angle)+pointMX[i]Math.sin(angle);
pointHX[i+1]=pointHX[i]Math.cos(angle)-Math.sin(angle)pointHY[i];
pointHY[i+1]=pointHY[i]Math.cos(angle)+pointHX[i]Math.sin(angle);
}
for(int i=0;i<60;i++)
{ pointSX[i]=pointSX[i]+120; //坐标平移
pointSY[i]=pointSY[i]+120;
pointMX[i]=pointMX[i]+120; //坐标平移
pointMY[i]=pointMY[i]+120;
pointHX[i]=pointHX[i]+120; //坐标平移
pointHY[i]=pointHY[i]+120;
}
secondLine=new Line2D.Double(0,0,0,0);
muniteLine=new Line2D.Double(0,0,0,0);
hourLine=new Line2D.Double(0,0,0,0);
secondTime.start(); //秒针开始计时
}
public void paint(Graphics g)
{ for(int i=0;i<60;i++) //绘制表盘上的小刻度和大刻度
{ int m=(int)pointSX[i];
int n=(int)pointSY[i];
if(i%5==0)
{ g.setColor(Color.red);
g.fillOval(m-4,n-4,8,8);
}
else
{ g.setColor(Color.cyan);
g.fillOval(m-2,n-2,4,4);
}
}
g.fillOval(115,115,10,10); //钟表中心的实心圆
Graphics2D g_2d=(Graphics2D)g;
g_2d.setColor(Color.red);
g_2d.draw(secondLine);
BasicStroke bs=
new BasicStroke(3f,BasicStroke.CAP_ROUND,BasicStroke.JOIN_MITER);
g_2d.setStroke(bs);
g_2d.setColor(Color.blue);
g_2d.draw(muniteLine);
bs=new BasicStroke(6f,BasicStroke.CAP_BUTT,BasicStroke.JOIN_MITER);
g_2d.setStroke(bs);
g_2d.setColor(Color.green);
g_2d.draw(hourLine);
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()==secondTime)
{ date=new Date();
String s=date.toString();
hour=Integer.parseInt(s.substring(11,13));
munite=Integer.parseInt(s.substring(14,16));
second=Integer.parseInt(s.substring(17,19)); //获取时间中的秒
int h=hour%12;
a=second; //秒针端点的坐标
b=munite; //分针端点的坐标
c=h5+munite/12; //时针端点的坐标
secondLine.setLine(120,120,(int)pointSX[a],(int)pointSY[a]);
muniteLine.setLine(120,120,(int)pointMX[b],(int)pointMY[b]);
hourLine.setLine(120,120,(int)pointHX[c],(int)pointHY[c]);
repaint();
}
}
}
public class Example14_12
{ public static void main(String args[])
{ Frame win=new Frame();
win.add(new Clock(),BorderLayout.CENTER);
win.setVisible(true);
win.setSize(246,280);
win.validate();
win.addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ System.exit(0);
}
} );
}
}
例子13
import java.applet.;
import java.awt.;
public class Example14_13 extends Applet
{ Image img;
public void start()
{ img=getImage(getCodeBase(),“vintdev.jpg”);
}
public void paint(Graphics g)
{ g.drawImage(img,22,72,100,100,this);
}
}
例子14
import java.awt.;
import java.awt.event.;
class Imagecanvas extends Canvas
{ Toolkit tool;
Image image;
Imagecanvas()
{ setSize(200,200);
tool=getToolkit();//得到一个Toolkit对象。
image=tool.getImage(“dog.gif”);//由tool负责获取图像。
}
public void paint(Graphics g)
{ g.drawImage(image,10,10,image.getWidth(this),image.getHeight(this),this);
}
public Image getImage()
{ return image;
}
}
public class Example14_14
{ public static void main(String args[])
{ Imagecanvas canvas=new Imagecanvas();
Frame frame=new Frame();
frame.add(canvas,BorderLayout.CENTER);
frame.setSize(300,300);
frame.setVisible(true);
frame.setIconImage(canvas.getImage());
frame.validate();
frame.addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ System.exit(0);
}
});
}
}
例子15
import com.sun.image.codec.jpeg.;
import java.awt.image.;
import java.awt.;
import java.util.;
import java.awt.event.;
import java.io.;
class PaintCanvas extends Canvas
{ int x=-1,y=-1;
Vector v=new Vector();
BufferedImage image;
Graphics2D g2D;
PaintCanvas()
{ image=new BufferedImage(300,300,BufferedImage.TYPE_INT_RGB);
g2D=image.createGraphics();
addMouseMotionListener(new MouseMotionAdapter()
{ public void mouseDragged(MouseEvent e)
{ x=(int)e.getX();y=(int)e.getY();
Point p=new Point(x,y);
v.addElement§;
if(x!=-1&&y!=-1)
{ for(int i=0;i<v.size()-1;i++)
{ Point p1=(Point)v.elementAt(i);
Point p2=(Point)v.elementAt(i+1);
//在图像image上绘制
g2D.drawLine(p1.x,p1.y,p2.x,p2.y);
}
repaint();
}
}
}
);
addMouseListener(new MouseAdapter()
{ public void mouseReleased(MouseEvent e)
{ v.removeAllElements();
}
}
);
}
public void paint(Graphics g)
{ g.drawImage(image,0,0,this) ; //将内存中的图像iamge绘制在画布上
}
public void update(Graphics g)
{ paint(g);
}
}
class WindowCanvas extends Frame implements ActionListener
{ PaintCanvas canvas=new PaintCanvas();
Button button=new Button(“save”);
WindowCanvas()
{ button.addActionListener(this);
add(canvas,BorderLayout.CENTER);
add(button,BorderLayout.NORTH);
setBounds(100,100,400,400);
setVisible(true);
}
public void actionPerformed(ActionEvent e)
{ try {JPEGImageEncoder encoder=
JPEGCodec.createJPEGEncoder(new FileOutputStream(“A.jpg”));
encoder.encode(canvas.image);
}
catch(Exception ee) {}
}
}
public class JPG
{ public static void main(String args[])
{ new WindowCanvas();
}
}
例子16
import java.awt.;import java.applet.;
public class PaintTest extends Applet
{ public void init()
{ setBackground(Color.yellow);
}
public void paint(Graphics g)
{ g.setXORMode(Color.red);
g.setColor(Color.green);
g.fillRect(20,20,80,40);
g.setColor(Color.yellow);
g.fillRect(60,20,80,40);
g.setColor(Color.green);
g.fillRect(20,70,80,40);
g.fillRect(60,70,80,40);
g.drawLine(100,100,200,200);
g.drawLine(100,100,220,220); //该直线消失
}
}
例子17
import java.awt.;
import java.awt.event.;
import java.awt.geom.;
public class Example14_17
{ public static void main(String args[])
{ Frame f=new Frame();
f.setSize(170,170);
f.setVisible(true);
f.addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ System.exit(0);
}
});
PrintJob p=f.getToolkit().getPrintJob(f,“ok”,null);
Graphics g=p.getGraphics();
g.drawRect(30,30,40,40);
g.dispose();
p.end();
}
}

第十五章 Java数据库连接(JDBC)
例子1
import java.sql.;
public class Example15_1
{ public static void main(String args[])
{ Connection con;
Statement sql;
ResultSet rs;
try { Class.forName(“sun.jdbc.odbc.JdbcOdbcDriver”);
}
catch(ClassNotFoundException e)
{ System.out.println(""+e);
}
try { con=DriverManager.getConnection(“jdbc:odbc:sun”,“gxy”,“123”);
sql=con.createStatement();
rs=sql.executeQuery(“SELECT * FROM chengjibiao”);
while(rs.next())
{ String number=rs.getString(1);
String name=rs.getString(2);
String date=rs.getString(3);
int math=rs.getInt(“math”);
int english=rs.getInt(“english”);
System.out.print(“学号：”+number);
System.out.print(" 姓名："+name);
System.out.print(" 出生："+date);
System.out.print(" 数学："+math);
System.out.println(" 英语："+english);
}
con.close();
}
catch(SQLException e)
{ System.out.println(e);
}
}
}
例子2
import java.sql.;
public class Example15_2
{ public static void main(String args[])
{ Connection con;
Statement sql;
ResultSet rs;
try { Class.forName(“sun.jdbc.odbc.JdbcOdbcDriver”);
}
catch(ClassNotFoundException e){}
try { con=DriverManager.getConnection(“jdbc:odbc:sun”,“gxy”,“123”);
sql=con.createStatement();
rs=sql.executeQuery(“SELECT name,english FROM chengjibiao WHERE english >= 80 “);
while(rs.next())
{ String name=rs.getString(1);
int english=rs.getInt(“english”);
System.out.print(” 姓名：”+name);
System.out.println(" 英语："+english);
}
con.close();
}
catch(SQLException e)
{ System.out.println(e);
}
}
}
例子3
import java.sql.;
public class Example15_3
{ public static void main(String args[])
{ Connection con;Statement sql; ResultSet rs;
try { Class.forName(“sun.jdbc.odbc.JdbcOdbcDriver”);
}
catch(ClassNotFoundException e)
{ System.out.println(""+e);
}
try { con=DriverManager.getConnection(“jdbc:odbc:sun”,“gxy”,“123”);
sql=
con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_READ_ONLY);
rs=sql.executeQuery(“SELECT name,english FROM chengjibiao”);
rs.last();
int number=rs.getRow();
System.out.println(“该表共有”+number+“条记录”);
rs.afterLast();
while(rs.previous())
{ String name=rs.getString(“name”);
int english=rs.getInt(“english”);
System.out.print(" 姓名："+name);
System.out.println(" 英语："+english);
}
System.out.println(“单独输出第5条记录:”);
rs.absolute(5);
String name=rs.getString(“name”);
int english=rs.getInt(“english”);
System.out.print(" 姓名："+name);
System.out.println(" 英语："+english);
con.close();
}
catch(SQLException e)
{ System.out.println(e);
}
}
}
例子4
import java.sql.;
public class Example15_4
{ public static void main(String args[])
{ Connection con;Statement sql; ResultSet rs;
try { Class.forName(“sun.jdbc.odbc.JdbcOdbcDriver”);
}
catch(ClassNotFoundException e){}
try { con=DriverManager.getConnection(“jdbc:odbc:sun”,“gxy”,“123”);
sql=con.createStatement();
String condition=“SELECT name,english FROM chengjibiao ORDER BY english”;
rs=sql.executeQuery(condition);
while(rs.next())
{ String name=rs.getString(1);
int english=rs.getInt(2);
System.out.print(" 姓名："+name);
System.out.println(" 英语："+english);
}
con.close();
}
catch(SQLException e)
{ System.out.println(e);
}
}
}
例子5
import java.sql.*;
public class Example15_5
{ public static void main(String args[])
{ Connection con;
Statement sql;
ResultSet rs;
try { Class.forName(“sun.jdbc.odbc.JdbcOdbcDriver”);
}
catch(ClassNotFoundException e){}
try { con=DriverManager.getConnection(“jdbc:odbc:sun”,“gxy”,“123”);
sql=con.createStatement();
rs=sql.executeQuery(“SELECT name,math FROM chengjibiao WHERE name LIKE ‘%小%’ “);
while(rs.next())
{ String name=rs.getString(1);
int math=rs.getInt(2);
System.out.print(” 姓名：”+name);
System.out.println(" 数学："+math);
}
con.close();
}
catch(SQLException e)
{ System.out.println(e);
}
}
}

例子6
import java.sql.;
import java.util.LinkedList;
public class Example15_6
{ public static void main(String args[])
{ LinkedList list=new LinkedList();
Connection con;
Statement sql;
ResultSet rs;
try{ Class.forName(“sun.jdbc.odbc.JdbcOdbcDriver”);
}
catch(ClassNotFoundException e){}
try { con=DriverManager.getConnection(“jdbc:odbc:sun”,“gxy”,“123”);
sql=
con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_READ_ONLY);
rs=sql.executeQuery(“SELECT name,math FROM chengjibiao”);
rs.last();
int lownumber=rs.getRow();
int number=lownumber;
for(int i=1;i<=number;i++)
{ list.add(new Integer(i));
}
double sum=0;
int k=4;
int 抽取数目=k;
while(k>0)
{ int i=(int)(Math.random()list.size());
int index=((Integer)list.get(i)).intValue();
rs.absolute(index);
System.out.print(“姓名:”+rs.getString(1));
System.out.println(“数学:”+rs.getString(2));
int math=rs.getInt(“math”);
sum=sum+math;
k–;
list.remove(i);
}
System.out.println(“抽样的数学平均成绩：”+sum/抽取数目);
con.close();
}
catch(SQLException e)
{ System.out.println(e);
}
}
}
例子7
import java.sql.;
public class Example15_7
{ public static void main(String args[])
{ Connection con;
Statement sql;
ResultSet rs;
try{ Class.forName(“sun.jdbc.odbc.JdbcOdbcDriver”);
}
catch(ClassNotFoundException e){}
try { con=DriverManager.getConnection(“jdbc:odbc:sun”,“gxy”,“123”);
sql=con.createStatement();
int math=99,english=0;
String number=“2003001”,date,name,recode,updateStr,insertStr,delStr;
updateStr=
“UPDATE chengjibiao SET math =”+math+" WHERE number = “+”’"+number+"’";
math=92;
english=66;
number=“2003039”;
name=“周王”;
date=“1999-12-28”;
recode= “(”+"’"+number+"’"+","+"’"+name+"’"+","+"’"+date+"’"+","+math+","+english+")";
insertStr=“INSERT INTO chengjibiao VALUES “+recode;
delStr=“DELETE FROM chengjibiao WHERE number = ‘2003004’ “;
sql.executeUpdate(updateStr);
sql.executeUpdate(insertStr);
sql.executeUpdate(delStr);
rs=sql.executeQuery(“SELECT * FROM chengjibiao”);
while(rs.next())
{ number=rs.getString(1);
name=rs.getString(2);
date=rs.getString(3);
math=rs.getInt(“math”);
english=rs.getInt(“english”);
System.out.print(“学号：”+number);
System.out.print(” 姓名：”+name);
System.out.print(” 出生：”+date);
System.out.print(" 数学："+math);
System.out.println(" 英语："+english);
}
con.close();
}
catch(SQLException e)
{ System.out.println(e);
}
}
}
例子8
import java.sql.;
public class Example15_8
{ public static void main(String args[])
{ Connection con;
PreparedStatement sql;
ResultSet rs;
try { Class.forName(“sun.jdbc.odbc.JdbcOdbcDriver”);
}
catch(ClassNotFoundException e)
{ System.out.println(""+e);
}
try { con=DriverManager.getConnection(“jdbc:odbc:sun”,“gxy”,“123”);
sql=con.prepareStatement(“SELECT * FROM chengjibiao”); //预处理语句
rs=sql.executeQuery();
while(rs.next())
{ String number=rs.getString(1);
String name=rs.getString(2);
System.out.print(“学号：”+number);
System.out.println(" 姓名："+name);
}
con.close();
}
catch(SQLException e)
{ System.out.println(e);
}
}
}
例子9
import java.sql.;
public class Example15_9
{ public static void main(String args[])
{ Connection con;
PreparedStatement sqlOne,sqlTwo,sqlThree;
ResultSet rs;
try{ Class.forName(“sun.jdbc.odbc.JdbcOdbcDriver”);
}
catch(ClassNotFoundException e){}
try { con=DriverManager.getConnection(“jdbc:odbc:sun”,“gxy”,“123”);
sqlOne=
con.prepareStatement(“UPDATE chengjibiao SET math = ? WHERE number= ? “);
sqlOne.setInt(1,100);
sqlOne.setString(2,“2003001”);
sqlOne.executeUpdate();
sqlOne.setInt(1,99);
sqlOne.setString(2,“2003002”);
sqlOne.executeUpdate();
sqlTwo=
con.prepareStatement(“INSERT INTO chengjibiao VALUES (?,?,?,?,?)”);
sqlTwo.setString(1,“2003888”);
sqlTwo.setString(2,“李向阳”);
sqlTwo.setString(3,“1919-05-04”);
sqlTwo.setInt(4,99);
sqlTwo.setInt(5,88);
sqlTwo.executeUpdate();
sqlThree=con.prepareStatement
(“SELECT number,math,english FROM chengjibiao WHERE english >= ? AND math >= ? “);
sqlThree.setInt(1,88);
sqlThree.setInt(2,90);
rs=sqlThree.executeQuery() ;
while(rs.next())
{ System.out.print(“学号：”+rs.getString(1));
System.out.print(” 数学：”+rs.getInt(2));
System.out.println(” 英语：”+rs.getInt(3));
}
con.close();
}
catch(SQLException e)
{ System.out.println(e);
}
}
}
例子10
（1） 客户端程序
Client.java
import java.net.;
import java.io.;
import java.awt.;
import java.awt.event.;
import javax.swing.;
public class Client
{
public static void main(String args[])
{ new QueryClient();
}
}
class QueryClient extends Frame
implements Runnable,ActionListener
{ Button connection,send;
TextField inputText;
TextArea showResult;
Socket socket=null;
DataInputStream in=null;
DataOutputStream out=null;
Thread thread;
QueryClient()
{ socket=new Socket();
Panel p=new Panel();
connection=new Button(“连接服务器”);
send=new Button(“发送”);
send.setEnabled(false);
inputText=new TextField(8);
showResult=new TextArea(6,42);
p.add(connection);
p.add(new Label(“输入学号”));
p.add(inputText);
p.add(send);
add(p,BorderLayout.NORTH);
add(showResult,BorderLayout.CENTER);
connection.addActionListener(this);
send.addActionListener(this);
thread=new Thread(this);
setBounds(10,30,350,400);
setVisible(true);
validate();
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{ System.exit(0);
}
});
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()==connection)
{ try
{ if(socket.isConnected())
{}
else
{ InetAddress address=InetAddress.getByName(“127.0.0.1”);
InetSocketAddress socketAddress=new InetSocketAddress(address,4331);
socket.connect(socketAddress);
in =new DataInputStream(socket.getInputStream());
out = new DataOutputStream(socket.getOutputStream());
send.setEnabled(true);
thread.start();
}
}
catch (IOException ee){}
}
if(e.getSource()==send)
{ String s=inputText.getText();
if(s!=null)
{ try { out.writeUTF(s);
}
catch(IOException e1){}
}
}
}
public void run()
{ String s=null;
while(true)
{ try{ s=in.readUTF();
showResult.append("\n"+s);
}
catch(IOException e)
{ showResult.setText(“与服务器已断开”);
break;
}
}
}
}
（2） 服务器端程序
Server.java
import java.io.;
import java.net.;
import java.util.;
import java.sql.;
public class Server
{ public static void main(String args[])
{ Connection con;
PreparedStatement sql=null;
ResultSet rs;
try{ Class.forName(“sun.jdbc.odbc.JdbcOdbcDriver”);
}
catch(ClassNotFoundException e){}
try{ con=DriverManager.getConnection(“jdbc:odbc:sun”,“gxy”,“123”);
sql=con.prepareStatement(“SELECT * FROM chengjibiao WHERE number = ? “);
}
catch(SQLException e){}
ServerSocket server=null;
Server_thread thread;
Socket you=null;
while(true)
{ try{ server=new ServerSocket(4331);
}
catch(IOException e1)
{ System.out.println(“正在监听”);
}
try{ System.out.println(” 等待客户呼叫”);
you=server.accept();
System.out.println(“客户的地址:”+you.getInetAddress());
}
catch(IOException e)
{ System.out.println(“正在等待客户”);