WEB容器监听器详解 ServletContextListener



WEB容器监听器ServletContextListener主要用来监听容器启动和 销毁的时候需要做一些操作，就可以使用这个监听器来做。

ServletContextListener在spring启动前启动。

我们实现一个简单的监听器，需要继承接口ServletContextListener：

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1.  * 一个测试的监听器例子  
2.  * @author zhuli  
3.  * @date 2014-7-26  
4.  */  
5. public class TestContextLister implements ServletContextListener {  
6.   
7.     @Override  
8.     public void contextInitialized(ServletContextEvent sce) {  
9.         System.out.println("==============================容器装载");  
10.   
11.     }  
12.   
13.     @Override  
14.     public void contextDestroyed(ServletContextEvent sce) {  
15.         System.out.println("==============================容器销毁");  
16.     }  
17.   
18. }  

 * 一个测试的监听器例子 * @author zhuli * @date 2014-7-26 */public class TestContextLister implements ServletContextListener {    @Override    public void contextInitialized(ServletContextEvent sce) {        System.out.println("==============================容器装载");    }    @Override    public void contextDestroyed(ServletContextEvent sce) {        System.out.println("==============================容器销毁");    }}

ServletContextListener 实现两个接口，一个是容器启动的时候，一个是容器销毁的时候：

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1. public interface ServletContextListener extends EventListener {  
2.     /** 
3.      ** Notification that the web application initialization 
4.      ** process is starting. 
5.      ** All ServletContextListeners are notified of context 
6.      ** initialization before any filter or servlet in the web 
7.      ** application is initialized. 
8.      */  
9.   
10.     public void contextInitialized ( ServletContextEvent sce );  
11.   
12.     /** 
13.      ** Notification that the servlet context is about to be shut down. 
14.      ** All servlets and filters have been destroy()ed before any 
15.      ** ServletContextListeners are notified of context 
16.      ** destruction. 
17.      */  
18.     public void contextDestroyed ( ServletContextEvent sce );  
19. }  

public interface ServletContextListener extends EventListener {/** ** Notification that the web application initialization ** process is starting. ** All ServletContextListeners are notified of context ** initialization before any filter or servlet in the web ** application is initialized. */    public void contextInitialized ( ServletContextEvent sce );/** ** Notification that the servlet context is about to be shut down. ** All servlets and filters have been destroy()ed before any ** ServletContextListeners are notified of context ** destruction. */    public void contextDestroyed ( ServletContextEvent sce );}

在web.xml中的配置：

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1. <listener>  
2.     <listener-class>com.xxx.controller.web.TestContextLister</listener-class>  
3. </listener>  

<listener><listener-class>com.xxx.controller.web.TestContextLister</listener-class></listener>

容器启动后，会在容器启动的日志中看到：

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1. ==============================容器装载  
2. 2014-07-26 08:54:01.302:INFO:/:Initializing Spring FrameworkServlet 'apiServlet'