Spring 容器中的 Bean 是有生命週期的，spring 允許 Bean 在初始化完成後以及銷燬前執行特定的操作。下面是常用的三種指定特定操作的方法：

• 通過實現InitializingBean/DisposableBean 介面來定製初始化之後/銷燬之前的操作方法；
• 通過<bean> 元素的 init-method/destroy-method屬性指定初始化之後 /銷燬之前呼叫的操作方法；
• 在指定方法上加上@PostConstruct或@PreDestroy註解來制定該方法是在初始化之後還是銷燬之前呼叫。

這幾種配置方式，執行順序是怎樣的呢？我們通過例子來研究下：

Java類：

1. import
    javax.annotation.PostConstruct;  
2. import javax.annotation.PreDestroy;  
3. import org.springframework.beans.factory.DisposableBean;  
4. import org.springframework.beans.factory.InitializingBean;  
5. import org.springframework.context.support.ClassPathXmlApplicationContext;  
6. publicclass InitAndDestroySeqBean 
   implements InitializingBean,DisposableBean {  
7.     public InitAndDestroySeqBean(){  
8.         System.out.println("執行InitAndDestroySeqBean: 構造方法");  
9.     }  
10.     @PostConstruct
11.     publicvoid postConstruct() {    
12.        System.out.println("執行InitAndDestroySeqBean: postConstruct");    
13.     }    
14.     @Override
15.     publicvoid afterPropertiesSet() throws Exception {  
16.         System.out.println("執行InitAndDestroySeqBean: afterPropertiesSet");   
17.     }  
18.     publicvoid initMethod() {  
19.         System.out.println("執行InitAndDestroySeqBean: init-method");  
20.     }  
21.     @PreDestroy
22.     publicvoid preDestroy()  {  
23.         System.out.println("執行InitAndDestroySeqBean: preDestroy");  
24.     }  
25.     @Override
26.     publicvoid destroy() throws Exception {  
27.         System.out.println("執行InitAndDestroySeqBean: destroy");  
28.     }  
29.     publicvoid destroyMethod() {  
30.         System.out.println("執行InitAndDestroySeqBean: destroy-method");  
31.     }  
32.     publicstaticvoid main(String[] args) {  
33.         ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("com/chj/spring/bean.xml");  
34.         context.close();  
35.     }  
36. }  

1. <?xmlversion="1.0"encoding="UTF-8"?>
2. <beansxmlns="http://www.springframework.org/schema/beans"
3.     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4.      xmlns:context="http://www.springframework.org/schema/context"
5.      xsi:schemaLocation="http://www.springframework.org/schema/beans    
6.  http://www.springframework.org/schema/beans/spring-beans-2.5.xsd    
7.  http://www.springframework.org/schema/context    
8.  http://www.springframework.org/schema/context/spring-context-2.5.xsd">
9.    <context:annotation-config/>
10.    <beanid="initAndDestroySeqBean"class="com.chj.spring.InitAndDestroySeqBean"init-method="initMethod"destroy-method="destroyMethod"/>
11. </beans>

1. 2013-03-03 17:11:19,098 DEBUG support.DefaultListableBeanFactory - Creating instance of bean 'initAndDestroySeqBean'  
2. 執行InitAndDestroySeqBean: 構造方法  
3. 2013-03-03 17:11:19,114 DEBUG annotation.CommonAnnotationBeanPostProcessor - Found init method on class [com.alibaba.chj.spring.InitAndDestroySeqBean]: public void com.alibaba.chj.spring.InitAndDestroySeqBean.postConstruct()  
4. 2013-03-03 17:11:19,114 DEBUG annotation.CommonAnnotationBeanPostProcessor - Found destroy method on class [com.alibaba.chj.spring.InitAndDestroySeqBean]: public void com.alibaba.chj.spring.InitAndDestroySeqBean.preDestroy()  
5. 2013-03-03 17:11:19,129 DEBUG support.DefaultListableBeanFactory - Eagerly caching bean 'initAndDestroySeqBean' to allow for resolving potential circular references  
6. 2013-03-03 17:11:19,129 DEBUG annotation.CommonAnnotationBeanPostProcessor - Invoking init method on bean 'initAndDestroySeqBean': public void com.alibaba.chj.spring.InitAndDestroySeqBean.postConstruct()  
7. 執行InitAndDestroySeqBean: postConstruct  
8. 2013-03-03 17:11:19,129 DEBUG support.DefaultListableBeanFactory - Invoking afterPropertiesSet() on bean with name 'initAndDestroySeqBean'  
9. 執行InitAndDestroySeqBean: afterPropertiesSet  
10. 2013-03-03 17:11:19,129 DEBUG support.DefaultListableBeanFactory - Invoking init method  'initMethod' on bean with name 'initAndDestroySeqBean'  
11. 執行InitAndDestroySeqBean: init-method  
12. 2013-03-03 17:11:19,129 DEBUG support.DefaultListableBeanFactory - Finished creating instance of bean 'initAndDestroySeqBean'  
13. 2013-03-03 17:11:19,129 INFO  support.ClassPathXmlApplicationContext - Closing org[email protected]56a499: display name [org[email protected]56a499]; startup date [Sun Mar 03 17:11:17 CST 2013]; root of context hierarchy  
14. 2013-03-03 17:11:19,129 INFO  support.DefaultListableBeanFactory - Destroying singletons in org.s[email protected]1292d26: defining beans [org.springframework.context.annotation.internalCommonAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,initAndDestroySeqBean]; root of factory hierarchy  
15. 2013-03-03 17:11:19,129 DEBUG annotation.CommonAnnotationBeanPostProcessor - Invoking destroy method on bean 'initAndDestroySeqBean': public void com.alibaba.chj.spring.InitAndDestroySeqBean.preDestroy()  
16. 執行InitAndDestroySeqBean: preDestroy  
17. 2013-03-03 17:11:19,145 DEBUG support.DisposableBeanAdapter - Invoking destroy() on bean with name 'initAndDestroySeqBean'  
18. 執行InitAndDestroySeqBean: destroy  
19. 2013-03-03 17:11:19,145 DEBUG support.DisposableBeanAdapter - Invoking destroy method 'destroyMethod' on bean with name 'initAndDestroySeqBean'  
20. 執行InitAndDestroySeqBean: destroy-method  

Bean在例項化的過程中：Constructor > @PostConstruct >InitializingBean > init-method

Bean在銷燬的過程中：@PreDestroy > DisposableBean > destroy-method