filter实现监听的三种方式

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wx62e9cee37942d 2022-08-04 16:54:52 博主文章分类：Jsp ©著作权

文章标签 filter实现监听 filter实现监听的三种方式监听的三种方式 java xml 文章分类 虚拟化云计算

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1方式一实现servletContextListener，代码如下：

package com.ask.listener;
 import javax.servlet.ServletContextEvent;
 import javax.servlet.ServletContextListener;
 public class Demo1 implements ServletContextListener{
    public Demo1(){
       System.out.println("Demo1");
    }
    public void contextDestroyed(ServletContextEvent arg0) {
       System.out.println("contextDestroyed");     
    }
    public void contextInitialized(ServletContextEvent arg0) {
       System.out.println("contextInitialized");
    }

方式二实现servletRequestListener，代码如下:

package com.ask.listener;
 import javax.servlet.ServletRequestEvent;
 import javax.servlet.ServletRequestListener;
 public class Demo2 implements ServletRequestListener{
    public Demo2(){
       System.out.println("Demo2");
    }
    public void requestDestroyed(ServletRequestEvent arg0) {
       System.out.println("requestDestroyed");
    }
    public void requestInitialized(ServletRequestEvent arg0) {
       System.out.println("requestInitialized");
    }
 }

方式三实现 httpSessionListener，代码如下:

package com.ask.listener;
 import javax.servlet.http.HttpSessionEvent;
 import javax.servlet.http.HttpSessionListener;
 public class Demo3 implements HttpSessionListener {
    public Demo3(){
       System.out.println("Demo3");
    }
    public void sessionCreated(HttpSessionEvent arg0) {
       System.out.println("sessionCreated");
    }
    public void sessionDestroyed(HttpSessionEvent arg0) {
       System.out.println("sessionDestroyed");
    }
 }

4.servlet中show类中代码如下:

package com.ask.servlet;
 import java.io.IOException;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import javax.servlet.http.HttpSession;
 public class Show extends HttpServlet {
     @Override
     protected void service(HttpServletRequest req, HttpServletResponse res)
           throws ServletException, IOException {
        HttpSession session=req.getSession();
        session.setMaxInactiveInterval(1);
        System.out.println("实现监听的三种方式");
        res.getWriter().write("实现监听的三种方式");
     }
 }

xml配置文件如下:

<?xml version="1.0" encoding="UTF-8"?>
 <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
 <display-name>firstServlet</display-name>
 <welcome-file-list>
 <welcome-file>index.html</welcome-file>
 <welcome-file>index.htm</welcome-file>
 <welcome-file>index.jsp</welcome-file>
 <welcome-file>default.html</welcome-file>
 <welcome-file>default.htm</welcome-file>
 <welcome-file>default.jsp</welcome-file>
 </welcome-file-list>
 <listener>
 <listener-class>com.ask.listener.Demo1</listener-class>
 </listener>
 <listener>
 <listener-class>com.ask.listener.Demo2</listener-class>
 </listener>
 <listener>
 <listener-class>com.ask.listener.Demo3</listener-class>
 </listener>
 <servlet>
 <servlet-name>show</servlet-name>
 <servlet-class>com.ask.servlet.Show</servlet-class>
 </servlet>
 <servlet-mapping>
 <servlet-name>show</servlet-name>
 <url-pattern>/show</url-pattern>
 </servlet-mapping>
 </web-app>