package com.etwin.gateway.shopping.utils; 

import java.io.BufferedReader; 
import java.io.IOException; 
import java.io.InputStream; 
import java.io.InputStreamReader; 
import java.net.SocketException; 
import java.text.ParseException; 
import java.util.ArrayList; 
import java.util.List; 

import org.apache.commons.net.ftp.FTPClient; 
import org.apache.commons.net.ftp.FTPFile; 

/** 
* @describe 读取FTP上的文件 
* @auto li.wang 
* @date 2013-11-18 下午4:07:34 
*/ 
public class FtpUtils { 

private FTPClient ftpClient; 
private String fileName, strencoding; 
private String ip = "113.108.96.3";        // 服务器IP地址 
private String userName = "test";        // 用户名 
private String userPwd = "test";        // 密码 
private int port = 21;      // 端口号 
private String path = "/SZX348/OPFQ/";        // 读取文件的存放目录 

/** 
  * init ftp servere 
  */ 
public FtpUtils() { 
  this.reSet(); 
} 

public void reSet() { 
  // 以当前系统时间拼接文件名 
  fileName = "20131112114850793835861000010161141169.txt"; 
  strencoding = "UTF-8"; 
  this.connectServer(ip, port, userName, userPwd, path); 
} 

/** 
  * @param ip 
  * @param port 
  * @param userName 
  * @param userPwd 
  * @param path 
  * @throws SocketException 
  * @throws IOException function:连接到服务器 
  */ 
public void connectServer(String ip, int port, String userName, String userPwd, String path) { 
  ftpClient = new FTPClient(); 
  try { 
   // 连接 
   ftpClient.connect(ip, port); 
   // 登录 
   ftpClient.login(userName, userPwd); 
   if (path != null && path.length() > 0) { 
    // 跳转到指定目录 
    ftpClient.changeWorkingDirectory(path); 
   } 
  } catch (SocketException e) { 
   e.printStackTrace(); 
  } catch (IOException e) { 
   e.printStackTrace(); 
  } 
} 

/** 
  * @throws IOException function:关闭连接 
  */ 
public void closeServer() { 
  if (ftpClient.isConnected()) { 
   try { 
    ftpClient.logout(); 
    ftpClient.disconnect(); 
   } catch (IOException e) { 
    e.printStackTrace(); 
   } 
  } 
} 

/** 
  * @param path 
  * @return function:读取指定目录下的文件名 
  * @throws IOException 
  */ 
public List<String> getFileList(String path) { 
  List<String> fileLists = new ArrayList<String>(); 
  // 获得指定目录下所有文件名 
  FTPFile[] ftpFiles = null; 
  try { 
   ftpFiles = ftpClient.listFiles(path); 
  } catch (IOException e) { 
   e.printStackTrace(); 
  } 
  for (int i = 0; ftpFiles != null && i < ftpFiles.length; i++) { 
   FTPFile file = ftpFiles[i]; 
   if (file.isFile()) { 
    fileLists.add(file.getName()); 
   } 
  } 
  return fileLists; 
} 

/** 
  * @param fileName 
  * @return function:从服务器上读取指定的文件 
  * @throws ParseException 
  * @throws IOException 
  */ 
public String readFile() throws ParseException { 
  InputStream ins = null; 
  StringBuilder builder = null; 
  try { 
   // 从服务器上读取指定的文件 
   ins = ftpClient.retrieveFileStream(fileName); 
   BufferedReader reader = new BufferedReader(new InputStreamReader(ins, strencoding)); 
   String line; 
   builder = new StringBuilder(150); 
   while ((line = reader.readLine()) != null) { 
    System.out.println(line); 
    builder.append(line); 
   } 
   reader.close(); 
   if (ins != null) { 
    ins.close(); 
   } 
   // 主动调用一次getReply()把接下来的226消费掉. 这样做是可以解决这个返回null问题 
   ftpClient.getReply(); 
  } catch (IOException e) { 
   e.printStackTrace(); 
  } 
  return builder.toString(); 
} 

/** 
  * @param fileName function:删除文件 
  */ 
public void deleteFile(String fileName) { 
  try { 
   ftpClient.deleteFile(fileName); 
  } catch (IOException e) { 
   e.printStackTrace(); 
  } 
} 

/** 
  * @param args 
  * @throws ParseException 
  */ 
public static void main(String[] args) throws ParseException { 
  FtpUtils ftp = new FtpUtils(); 
  String str = ftp.readFile(); 
  System.out.println(str); 
} 
}

转自 http://www.cxyclub.cn/n/50660/