1.生命周期的流程图:

Spring Bean 的完整生命周期从创建spring容器开始,直到最终的Spring容器销毁Bean,这其中包含了一系列的关键点。

若容器注册了以上各种接口,程序那么将会按照以上的流程进行。下面将仔细讲解各接口的作用。

2.各种接口方法分类:

Bean的完整生命周经历了各种方法的调用,这些方法可以划分为以下几个类:

1.Bean自身的方法:这个包括了Bean本身调用的方法通过配置文件中的<bean>的init-method和destroy-method指定的方法;

2.Bean级生命周期接口的方法:这个包括了BeanNameAware、BeanFactoryAware、InitializingBean和DiposableBean这些接口的方法

3.容量级生命周期接口的方法:这包括了InstantiationAwareBeanPostProcessor和BeanPostProcessor 这两个接口实现,一般称它们的实现类为“后处理器”。

4.工厂后处理器接口方法:这个包括了AspectJWeavingEnabler,ConfigurationClassPostProcessor, CustomAutowireConfigurer等等非常有用的工厂后处理器接口的方法。工厂后处理器也是容器级的。在应用上下文装配配置文件之后立即调用。

3.演示:

我们用一个简单Spring Bean来演示一下Spring Bean的生命周期。

1.首先是一个简单的Spring Bean ,调用Bean 自身的方法和Bean级生命周期接口的方法,为了方便演示,它实现了BeanNameAware、BeanFactoryAware、InitializingBean和DiposableBean这4个接口,同时有2个方法,对应配置文件中<bean> init-method和destroy-method。如下:

 package springBeanTest;
 2 
 3 import org.springframework.beans.BeansException;
 4 import org.springframework.beans.factory.BeanFactory;
 5 import org.springframework.beans.factory.BeanFactoryAware;
 6 import org.springframework.beans.factory.BeanNameAware;
 7 import org.springframework.beans.factory.DisposableBean;
 8 import org.springframework.beans.factory.InitializingBean;
 9 
10 /**
11  * @author qsk
12  */
13 public class Person implements BeanFactoryAware, BeanNameAware,
14         InitializingBean, DisposableBean {
15 
16     private String name;
17     private String address;
18     private int phone;
19 
20     private BeanFactory beanFactory;
21     private String beanName;
22 
23     public Person() {
24         System.out.println("【构造器】调用Person的构造器实例化");
25     }
26 
27     public String getName() {
28         return name;
29     }
30 
31     public void setName(String name) {
32         System.out.println("【注入属性】注入属性name");
33         this.name = name;
34     }
35 
36     public String getAddress() {
37         return address;
38     }
39 
40     public void setAddress(String address) {
41         System.out.println("【注入属性】注入属性address");
42         this.address = address;
43     }
44 
45     public int getPhone() {
46         return phone;
47     }
48 
49     public void setPhone(int phone) {
50         System.out.println("【注入属性】注入属性phone");
51         this.phone = phone;
52     }
53 
54     @Override
55     public String toString() {
56         return "Person [address=" + address + ", name=" + name + ", phone="
57                 + phone + "]";
58     }
59 
60     // 这是BeanFactoryAware接口方法
61     @Override
62     public void setBeanFactory(BeanFactory arg0) throws BeansException {
63         System.out
64                 .println("【BeanFactoryAware接口】调用BeanFactoryAware.setBeanFactory()");
65         this.beanFactory = arg0;
66     }
67 
68     // 这是BeanNameAware接口方法
69     @Override
70     public void setBeanName(String arg0) {
71         System.out.println("【BeanNameAware接口】调用BeanNameAware.setBeanName()");
72         this.beanName = arg0;
73     }
74 
75     // 这是InitializingBean接口方法
76     @Override
77     public void afterPropertiesSet() throws Exception {
78         System.out
79                 .println("【InitializingBean接口】调用InitializingBean.afterPropertiesSet()");
80     }
81 
82     // 这是DiposibleBean接口方法
83     @Override
84     public void destroy() throws Exception {
85         System.out.println("【DiposibleBean接口】调用DiposibleBean.destory()");
86     }
87 
88     // 通过<bean>的init-method属性指定的初始化方法
89     public void myInit() {
90         System.out.println("【init-method】调用<bean>的init-method属性指定的初始化方法");
91     }
92 
93     // 通过<bean>的destroy-method属性指定的初始化方法
94     public void myDestory() {
95         System.out.println("【destroy-method】调用<bean>的destroy-method属性指定的初始化方法");
96     }
97 }

2、接下来是演示BeanPostProcessor接口的方法,如下:

package springBeanTest;
 2 
 3 import org.springframework.beans.BeansException;
 4 import org.springframework.beans.factory.config.BeanPostProcessor;
 5 
 6 public class MyBeanPostProcessor implements BeanPostProcessor {
 7 
 8     public MyBeanPostProcessor() {
 9         super();
10         System.out.println("这是BeanPostProcessor实现类构造器!!");
11         // TODO Auto-generated constructor stub
12     }
13 
14     @Override
15     public Object postProcessAfterInitialization(Object arg0, String arg1)
16             throws BeansException {
17         System.out
18         .println("BeanPostProcessor接口方法postProcessAfterInitialization对属性进行更改!");
19         return arg0;
20     }
21 
22     @Override
23     public Object postProcessBeforeInitialization(Object arg0, String arg1)
24             throws BeansException {
25         System.out
26         .println("BeanPostProcessor接口方法postProcessBeforeInitialization对属性进行更改!");
27         return arg0;
28     }
29 }

 如上,BeanPostProcessor接口包括2个方法postProcessAfterInitialization和postProcessBeforeInitialization,这两个方法的第一个参数都是要处理的Bean对象,第二个参数都是Bean的name。返回值也都是要处理的Bean对象。这里要注意。

3、InstantiationAwareBeanPostProcessor 接口本质是BeanPostProcessor的子接口,一般我们继承Spring为其提供的适配器类InstantiationAwareBeanPostProcessor Adapter来使用它,如下:

package springBeanTest;
 2 
 3 import java.beans.PropertyDescriptor;
 4 
 5 import org.springframework.beans.BeansException;
 6 import org.springframework.beans.PropertyValues;
 7 import org.springframework.beans.factory.config.InstantiationAwareBeanPostProcessorAdapter;
 8 
 9 public class MyInstantiationAwareBeanPostProcessor extends
10         InstantiationAwareBeanPostProcessorAdapter {
11 
12     public MyInstantiationAwareBeanPostProcessor() {
13         super();
14         System.out
15                 .println("这是InstantiationAwareBeanPostProcessorAdapter实现类构造器!!");
16     }
17 
18     // 接口方法、实例化Bean之前调用
19     @Override
20     public Object postProcessBeforeInstantiation(Class beanClass,
21             String beanName) throws BeansException {
22         System.out
23                 .println("InstantiationAwareBeanPostProcessor调用postProcessBeforeInstantiation方法");
24         return null;
25     }
26 
27     // 接口方法、实例化Bean之后调用
28     @Override
29     public Object postProcessAfterInitialization(Object bean, String beanName)
30             throws BeansException {
31         System.out
32                 .println("InstantiationAwareBeanPostProcessor调用postProcessAfterInitialization方法");
33         return bean;
34     }
35 
36     // 接口方法、设置某个属性时调用
37     @Override
38     public PropertyValues postProcessPropertyValues(PropertyValues pvs,
39             PropertyDescriptor[] pds, Object bean, String beanName)
40             throws BeansException {
41         System.out
42                 .println("InstantiationAwareBeanPostProcessor调用postProcessPropertyValues方法");
43         return pvs;
44     }
45 }

这个有3个方法,其中第二个方法postProcessAfterInitialization就是重写了BeanPostProcessor的方法。第三个方法postProcessPropertyValues用来操作属性,返回值也应该是PropertyValues对象。

4、演示工厂后处理器接口方法,如下:

package springBeanTest;
 2 
 3 import org.springframework.beans.BeansException;
 4 import org.springframework.beans.factory.config.BeanDefinition;
 5 import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
 6 import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
 7 
 8 public class MyBeanFactoryPostProcessor implements BeanFactoryPostProcessor {
 9 
10     public MyBeanFactoryPostProcessor() {
11         super();
12         System.out.println("这是BeanFactoryPostProcessor实现类构造器!!");
13     }
14 
15     @Override
16     public void postProcessBeanFactory(ConfigurableListableBeanFactory arg0)
17             throws BeansException {
18         System.out
19                 .println("BeanFactoryPostProcessor调用postProcessBeanFactory方法");
20         BeanDefinition bd = arg0.getBeanDefinition("person");
21         bd.getPropertyValues().addPropertyValue("phone", "110");
22     }
23 
24 }

 5、配置文件如下beans.xml,很简单,使用ApplicationContext,处理器不用手动注册:

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="
            http://www.springframework.org/schema/beans 
            http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">

    <bean id="beanPostProcessor" class="springBeanTest.MyBeanPostProcessor">
    </bean>

    <bean id="instantiationAwareBeanPostProcessor" class="springBeanTest.MyInstantiationAwareBeanPostProcessor">
    </bean>

    <bean id="beanFactoryPostProcessor" class="springBeanTest.MyBeanFactoryPostProcessor">
    </bean>
    
    <bean id="person" class="springBeanTest.Person" init-method="myInit"
        destroy-method="myDestory" scope="singleton" p:name="张三" p:address="广州"
        p:phone="15900000000" />

</beans>

6.下面测试一下: 

 1 package springBeanTest;
 2 
 3 import org.springframework.context.ApplicationContext;
 4 import org.springframework.context.support.ClassPathXmlApplicationContext;
 5 
 6 public class BeanLifeCycle {
 7 
 8     public static void main(String[] args) {
 9 
10         System.out.println("现在开始初始化容器");
11         
12         ApplicationContext factory = new ClassPathXmlApplicationContext("springBeanTest/beans.xml");
13         System.out.println("容器初始化成功");    
14         //得到Preson,并使用
15         Person person = factory.getBean("person",Person.class);
16         System.out.println(person);
17         
18         System.out.println("现在开始关闭容器!");
19         ((ClassPathXmlApplicationContext)factory).registerShutdownHook();
20     }
21 }

关闭容器使用的是实际是AbstractApplicationContext的钩子方法。

 我们来看一下结果:

现在开始初始化容器
2014-5-18 15:46:20 org.springframework.context.support.AbstractApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@19a0c7c: startup date [Sun May 18 15:46:20 CST 2014]; root of context hierarchy
2014-5-18 15:46:20 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [springBeanTest/beans.xml]
这是BeanFactoryPostProcessor实现类构造器!!
BeanFactoryPostProcessor调用postProcessBeanFactory方法
这是BeanPostProcessor实现类构造器!!
这是InstantiationAwareBeanPostProcessorAdapter实现类构造器!!
2014-5-18 15:46:20 org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons
信息: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@9934d4: defining beans [beanPostProcessor,instantiationAwareBeanPostProcessor,beanFactoryPostProcessor,person]; root of factory hierarchy
InstantiationAwareBeanPostProcessor调用postProcessBeforeInstantiation方法
【构造器】调用Person的构造器实例化
InstantiationAwareBeanPostProcessor调用postProcessPropertyValues方法
【注入属性】注入属性address
【注入属性】注入属性name
【注入属性】注入属性phone
【BeanNameAware接口】调用BeanNameAware.setBeanName()
【BeanFactoryAware接口】调用BeanFactoryAware.setBeanFactory()
BeanPostProcessor接口方法postProcessBeforeInitialization对属性进行更改!
【InitializingBean接口】调用InitializingBean.afterPropertiesSet()
【init-method】调用<bean>的init-method属性指定的初始化方法
BeanPostProcessor接口方法postProcessAfterInitialization对属性进行更改!
InstantiationAwareBeanPostProcessor调用postProcessAfterInitialization方法
容器初始化成功
Person [address=广州, name=张三, phone=110]
现在开始关闭容器!
【DiposibleBean接口】调用DiposibleBean.destory()
【destroy-method】调用<bean>的destroy-method属性指定的初始化方法

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