`
SilverRing
  • 浏览: 71332 次
社区版块
存档分类
最新评论

summary of Spring bean lifecycle management

BeanSpringXMLthreadServlet 
阅读更多

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. }  
分享到：
| stax conflict between weblogic 9.2 and x ...
评论
1 楼 SilverRing 2007-04-04  
Another method of implementing shutdown hook is to let the class implement BeanFactoryAware interface. 

public class ShutdownHookBean implements BeanFactoryAware,
        Runnable {
    
    private ConfigurableListableBeanFactory factory;
    
    public void setBeanFactory(BeanFactory factory) throws BeansException {
    
        if (factory instanceof ConfigurableListableBeanFactory) {
            this.factory = (ConfigurableListableBeanFactory) factory;
            Runtime.getRuntime().addShutdownHook(new Thread(this));
        }
    }
    
    public void run() {
        if (factory != null) {
            System.out.println("Destroying Singletons");
            factory.destroySingletons();
            System.out.println("Singletons Destroyed");
        }
    }
}


And the main method should be like this: 

    public static void main(String[] args) {
        ConfigurableListableBeanFactory factory = new XmlBeanFactory(
                new FileSystemResource(
                        "./shutdownHook.xml"));
    
        // make sure the shutdown hook is created
        factory.preInstantiateSingletons();
    
        DestructiveBeanWithInterface bean =  
        (DestructiveBeanWithInterface)factory.getBean("destructiveBean");
    }


Note the call to ConfigurableListableBeanFactory.preInstantiateSingletons(). By default, Spring lazily instantiates singleton beans as they are needed. Invoking preInstantiateSingletons() causes Spring to run through all its singleton bean definitions and create the instances.
发表评论

您还没有登录,请您登录后再发表评论

相关推荐

Magicbox
Global site tag (gtag.js) - Google Analytics