1. 监听器

 1 package com.eagle.listener;
 2 
 3 import javax.servlet.ServletRequestEvent;
 4 import javax.servlet.ServletRequestListener;
 5 
 6 public class MyServletRequestListener implements ServletRequestListener {
 7 
 8     public MyServletRequestListener() {
 9         super();
10         System.out.println("request对象的构造方法");
11     }
12 
13     public void requestInitialized(ServletRequestEvent sre) {
14         System.out.println("request创建了！");
15     }
16 
17     public void requestDestroyed(ServletRequestEvent sre) {
18         System.out.println("request对象销毁了！");
19     }
20 
21 }

1   <listener>
2     <listener-class>com.eagle.listener.MyServletRequestListener</listener-class>
3   </listener>

 1 package com.eagle.listener;
 2 
 3 import javax.servlet.http.HttpSessionEvent;
 4 import javax.servlet.http.HttpSessionListener;
 5 
 6 public class MyHttpSessionListener implements HttpSessionListener {
 7 
 8     public MyHttpSessionListener() {
 9 
10         super();
11         System.out.println("session对象构造方法");
12     }
13 
14     public void sessionCreated(HttpSessionEvent arg0) {
15         System.out.println("创建session对象");
16     }
17 
18     public void sessionDestroyed(HttpSessionEvent arg0) {
19         System.out.println("销毁session对象");
20     }
21 
22 }

 1 package com.eagle.web;
 2 
 3 import java.io.IOException;
 4 import javax.servlet.ServletException;
 5 import javax.servlet.http.HttpServlet;
 6 import javax.servlet.http.HttpServletRequest;
 7 import javax.servlet.http.HttpServletResponse;
 8 import javax.servlet.http.HttpSession;
 9 
10 public class CreateSession extends HttpServlet {
11 
12     private static final long serialVersionUID = 1L;
13 
14     public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
15         request.setCharacterEncoding("utf-8");
16         response.setContentType("text/html;charset=utf-8"); 
17         HttpSession httpSession = request.getSession();
18         httpSession.setMaxInactiveInterval(10);
19         String id = httpSession.getId();
20         if(httpSession.isNew()) {
21             httpSession.setAttribute("name", "狼");        
22             String name = (String) httpSession.getAttribute("name");
23             response.getWriter().print("恭喜session创建成功，sessionid="+id+";name="+name);
24         }else {
25             String name = (String) httpSession.getAttribute("name");
26             response.getWriter().print("服务器已经存在session了，sessionid="+id+";name="+name);
27         }
28     }
29 
30     public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
31         doGet(request, response);
32     }
33 }

1   <listener>
2     <listener-class>com.eagle.listener.MyHttpSessionListener</listener-class>
3   </listener>

 1 package com.eagle.listener;
 2 
 3 import javax.servlet.ServletContextEvent;
 4 import javax.servlet.ServletContextListener;
 5 
 6 public class MyServletContextListener implements ServletContextListener {
 7 
 8     public MyServletContextListener() {
 9         System.out.println("ServletContext对象构建！");
10     }
11 
12     public void contextInitialized(ServletContextEvent sce) {
13         System.out.println("ServletContext对象初始化！");
14     }
15     
16     public void contextDestroyed(ServletContextEvent sce) {
17         System.out.println("ServletContext对象销毁！");
18     }
19 }

1  <listener>
2       <listener-class>com.eagle.listener.MyServletContextListener</listener-class>
3   </listener>