summary of Spring bean lifecycle management

In general, two lifecycle events are particularly relevant to a bean: post-initialization and pre-destruction. Both of these lifecycle events are only fired for beans that are singletons.

1. post-initialization event. 2 ways to implement it: method-based and interface-based.

1) method based. Specify the init method name in the configuration file (init-method="method name").

xml

1. <bean id="simpleBean1"    
2.       class="SimpleBean"    
3.       init-method="init">  
4.     <property name="age">  
5.         <value>100value>  
6.     property>  
7. bean>  

 

2) interface based. Implement InitializingBean interface and define afterPropertiesSet() method.

java

1. public class SimpleBeanWithInterface implements InitializingBean {   
2.        
3.     public void afterPropertiesSet() throws Exception {   
4.         System.out.println("Initializing bean");   
5.     }   
6. }  

 

2. pre-destruction event. 2 ways to implement it: method-based and interface-based.

1) method based. Specify the destroy mothod in the config file. (destroy-method="method name")

xml

1. <bean id="destructiveBean"    
2.       class="DestructiveBean"  
3.       destroy-method="destroy">  
4.     <property name="filePath">  
5.         <value>d:/tmp/test.txtvalue>  
6.     property>  
7. bean>  

2) interface based. Implement DisposableBean interface and define destroy() method.

java

1. public class DestructiveBeanWithInterface implements DisposableBean {   
2.        
3.     public void destroy() {   
4.        
5.         System.out.println("Destroying Bean");   
6.     }   
7. }   

Destruction callbacks are not fired automatically. You need to remember to call destroySingletons() before the application is closed. When the application runs as a servlet, you can simple call the method in the servlet's destroy() method. However, in a stand-alone application, you need to take advantage of the Java's shutdown hook, a thread executed just before the application shuts down.

java

1. public class ShutdownHook implements Runnable {   
2.        
3.     private ConfigurableListableBeanFactory factory;   
4.        
5.     public ShutdownHook(ConfigurableListableBeanFactory factory) {   
6.         this.factory = factory;   
7.     }   
8.        
9.     public void run() {   
10.         System.out.println("Destroying Singletons");   
11.         factory.destroySingletons();   
12.         System.out.println("Singletons Destroyed");   
13.     }   
14.        
15. }  

Register this Thread as a shutdown hook using Runtime.addShutdownHook(). 

java

1. public class ShutdownHookExample {   
2.        
3.     public static void main(String[] args) {   
4.         ConfigurableListableBeanFactory factory = new XmlBeanFactory(   
5.                 new FileSystemResource(   
6.                         "./disposeInterface.xml"));   
7.        
8.         Runtime.getRuntime().addShutdownHook(   
9.                 new Thread(new ShutdownHook(factory)));   
10.         DestructiveBeanWithInterface bean =     
11.         (DestructiveBeanWithInterface)factory.getBean("destructiveBean");   
12.     }   
13. }