首先,什么是监听器?
监听器主要有以下几种:
现在,我们来一一试过,把所有的事件监听器全部写好,按照输出,我们来分析:
首先是:ServletContextEvent事件:
- package com.xust.jia.listener;
- import java.text.SimpleDateFormat;
- import java.util.Date;
- import javax.servlet.ServletContextEvent;
- import javax.servlet.ServletContextListener;
- public class Listenerapplication implements ServletContextListener{
- @Override
- public void contextDestroyed(ServletContextEvent arg0) {
- // TODO Auto-generated method stub
- SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
- System.out.println();
- System.out.println();
- System.out.println(sdf.format(new Date())+"application结束");
- System.out.println();
- System.out.println();
- }
- @Override
- public void contextInitialized(ServletContextEvent arg0) {
- // TODO Auto-generated method stub
- SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
- System.out.println();
- System.out.println();
- System.out.println(sdf.format(new Date())+"application开始");
- System.out.println();
- System.out.println();
- }
- }
接下来是
ServletContextAttributeEvent:
- package com.xust.jia.listener;
- import java.text.SimpleDateFormat;
- import java.util.Date;
- import javax.servlet.ServletContextAttributeEvent;
- import javax.servlet.ServletContextAttributeListener;
- public class Listernerapplicationattr implements ServletContextAttributeListener{
- @Override
- public void attributeAdded(ServletContextAttributeEvent arg0) {
- // TODO Auto-generated method stub
- SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
- System.out.println();
- System.out.println();
- System.out.println(sdf.format(new Date())+"application的属性被新建"+arg0.getName());
- System.out.println();
- System.out.println();
- }
- @Override
- public void attributeRemoved(ServletContextAttributeEvent arg0) {
- // TODO Auto-generated method stub
- SimpleDateFormat sdFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
- System.out.println();
- System.out.println();
- System.out.println(sdFormat.format(new Date())+"application的"+arg0.getName()+"属性被删除");
- System.out.println();
- System.out.println();
- }
- @Override
- public void attributeReplaced(ServletContextAttributeEvent arg0) {
- // TODO Auto-generated method stub
- SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
- System.out.println();
- System.out.println();
- System.out.println(sdf.format(new Date())+"application的"+arg0.getName()+"属性值被修改为:"+arg0.getValue());
- System.out.println();
- System.out.println();
- }
- }
- package com.xust.jia.listener;
- import java.text.SimpleDateFormat;
- import java.util.Date;
- import javax.servlet.http.HttpSessionEvent;
- import javax.servlet.http.HttpSessionListener;
- public class Listenersession implements HttpSessionListener{
- @Override
- public void sessionCreated(HttpSessionEvent se) {
- // TODO Auto-generated method stub
- SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
- System.out.println();
- System.out.println();
- System.out.println(sdf.format(new Date()) + "session对象被创建" + se.getSession());
- System.out.println();
- System.out.println();
- }
- @Override
- public void sessionDestroyed(HttpSessionEvent se) {
- // TODO Auto-generated method stub
- SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
- System.out.println();
- System.out.println();
- System.out.println(sdf.format(new Date())+"session对象被销毁" + se.getSource()+se.getClass());
- System.out.println();
- System.out.println();
- }
- }
HttpSessionEvent事件的HttpSessionActivationListener接口:
这个接口并不是直接监听的,而是依附于具体的实体类对象中,即由具体需要的实体类进行实现这个接口,实现这个接口所定义的方法,这样,当在使用到这个实体类的对象时,就会触发这个监听器,从而执行对应的方法:
首先,我们现在实体类中实现这个接口:
- package com.xust.jia.listener;
- import java.text.SimpleDateFormat;
- import java.util.Date;
- import javax.servlet.http.HttpSessionActivationListener;
- import javax.servlet.http.HttpSessionEvent;
- public class Man implements HttpSessionActivationListener{
- @Override
- public void sessionDidActivate(HttpSessionEvent se) {
- // TODO Auto-generated method stub
- SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
- System.out.println();
- System.out.println();
- System.out.println(sdf.format(new Date()) +"这是session的didActive方法");
- System.out.println();
- System.out.println();
- }
- @Override
- public void sessionWillPassivate(HttpSessionEvent se) {
- // TODO Auto-generated method stub
- SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
- System.out.println();
- System.out.println();
- System.out.println(sdf.format(new Date())+"这是session的Willpassivate方法");
- System.out.println();
- System.out.println();
- }
- public Man() {
- super();
- // TODO Auto-generated constructor stub
- }
- }
- <%@page import="java.text.SimpleDateFormat"%>
- <%@page import="com.xust.jia.listener.Man"%>
- <%@page import="java.util.Date" %>
- <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
- <%
- String path = request.getContextPath();
- String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
- %>
- <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
- <html>
- <head>
- <base href="<%=basePath%>">
- <title>这是测试session的activationListener接口</title>
- <meta http-equiv="pragma" content="no-cache">
- <meta http-equiv="cache-control" content="no-cache">
- <meta http-equiv="expires" content="0">
- <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
- <meta http-equiv="description" content="This is my page">
- <!--
- <link rel="stylesheet" type="text/css" href="styles.css">
- -->
- </head>
- <body>
- <h1>测试session的activationListener接口</h1>
- <%
- if(session.getAttribute("act") == null)
- {
- Man man = new Man();
- session.setAttribute("act", man);
- }
- System.out.println(session.getId()+session.getAttribute("act"));
- Date d = new Date(session.getCreationTime());
- System.out.println(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(d));
- %>
- </body>
- </html>
其中,htmlday1是项目名称,然后,在里面写入:
接下来,我们先打开配置的xml,然后通过xml来访问测试页面进行测试:
说明这个测试页面里的语句被执行,然后关闭服务器,重新打开服务器,发现在E:盘下多了一个文件夹,a:
发现多了一个SESSION文件,打开如下:
在控制台输出以下信息:
注意,关闭服务器是正常关闭,不是直接关闭。
HttpSessionBindingEvent事件的HttpSessionAttributeListener接口:
- package com.xust.jia.listener;
- import java.text.SimpleDateFormat;
- import java.util.Date;
- import javax.servlet.http.HttpSessionAttributeListener;
- import javax.servlet.http.HttpSessionBindingEvent;
- public class Listenersessionattr implements HttpSessionAttributeListener{
- @Override
- public void attributeAdded(HttpSessionBindingEvent event) {
- // TODO Auto-generated method stub
- SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
- System.out.println();
- System.out.println();
- System.out.println(sdf.format(new Date())+"session的"+event.getName()+"属性被增加,值为:"+event.getValue());
- System.out.println();
- System.out.println();
- }
- @Override
- public void attributeRemoved(HttpSessionBindingEvent event) {
- // TODO Auto-generated method stub
- SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
- System.out.println();
- System.out.println();
- System.out.println(sdf.format(new Date())+"session的"+event.getName()+"属性被删除,值为:"+event.getValue());
- System.out.println();
- System.out.println();
- }
- @Override
- public void attributeReplaced(HttpSessionBindingEvent event) {
- // TODO Auto-generated method stub
- SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
- System.out.println();
- System.out.println();
- System.out.println(sdf.format(new Date())+"session的"+event.getName()+"属性值被修改为:"+event.getValue());
- System.out.println();
- System.out.println();
- }
- }
HttpSessionBindingEvent事件的HttpSessionBindingListener接口:
因为这个接口比较特殊,是在实体类中进行实现方法,而且不需要在Web.xml文件中进行配置,所以,我们只是简单的检测验证一下这个接口:
- package com.xust.jia.listener;
- import java.text.SimpleDateFormat;
- import java.util.Date;
- import javax.servlet.http.HttpSessionBindingEvent;
- import javax.servlet.http.HttpSessionBindingListener;
- public class Person implements HttpSessionBindingListener{
- @Override
- public void valueBound(HttpSessionBindingEvent event) {
- // TODO Auto-generated method stub
- SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
- System.out.println();
- System.out.println();
- System.out.println(sdf.format(new Date())+"这是Binding的Bound"+event.getName()+event.getValue());
- System.out.println();
- System.out.println();
- }
- @Override
- public void valueUnbound(HttpSessionBindingEvent event) {
- // TODO Auto-generated method stub
- SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
- System.out.println();
- System.out.println();
- System.out.println(sdf.format(new Date())+"这是Binding的Unbound"+event.getName()+event.getValue());
- System.out.println();
- System.out.println();
- }
- public Person() {
- super();
- // TODO Auto-generated constructor stub
- }
- }
接下来,我们在servlet类中进行调用这个类,然后把这个类对象加载到会话的属性中,最后使用session的方法,销毁这个session:
在servlet的post或者get方法中写入如下代码:
- Person person = new Person();
- HttpSession hsHttpSession = request.getSession();
- hsHttpSession.setAttribute("person", person);
- hsHttpSession.invalidate();
接下来,我们调入这个servlet方法中,进行测试:
显示结果如下:
ServletRequestEvent事件:
- package com.xust.jia.listener;
- import java.text.SimpleDateFormat;
- import java.util.Date;
- import javax.servlet.ServletRequestEvent;
- import javax.servlet.ServletRequestListener;
- public class Listenerrequest implements ServletRequestListener{
- @Override
- public void requestDestroyed(ServletRequestEvent arg0) {
- // TODO Auto-generated method stub
- SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
- System.out.println();
- System.out.println();
- System.out.println(sdf.format(new Date())+"request被创建");
- System.out.println();
- System.out.println();
- }
- @Override
- public void requestInitialized(ServletRequestEvent arg0) {
- // TODO Auto-generated method stub
- SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
- System.out.println();
- System.out.println();
- System.out.println(sdf.format(new Date())+"request被销毁");
- System.out.println();
- System.out.println();
- }
- }
ServletRequestAttributeEvent事件:
- package com.xust.jia.listener;
- import java.text.SimpleDateFormat;
- import java.util.Date;
- import javax.servlet.ServletRequestAttributeEvent;
- import javax.servlet.ServletRequestAttributeListener;
- public class Listenerrequestattr implements ServletRequestAttributeListener{
- @Override
- public void attributeAdded(ServletRequestAttributeEvent arg0) {
- // TODO Auto-generated method stub
- SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
- System.out.println();
- System.out.println();
- System.out.println(sdf.format(new Date())+"request的"+arg0.getName()+"属性被创建,值为:"+arg0.getValue());
- System.out.println();
- System.out.println();
- }
- @Override
- public void attributeRemoved(ServletRequestAttributeEvent arg0) {
- // TODO Auto-generated method stub
- SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
- System.out.println();
- System.out.println();
- System.out.println(sdf.format(new Date())+"request的"+arg0.getName()+"属性被删除,值为:"+arg0.getValue());
- System.out.println();
- System.out.println();
- }
- @Override
- public void attributeReplaced(ServletRequestAttributeEvent arg0) {
- // TODO Auto-generated method stub
- SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
- System.out.println();
- System.out.println();
- System.out.println(sdf.format(new Date())+"request的"+arg0.getName()+"属性被修改,值为:"+arg0.getValue());
- System.out.println();
- System.out.println();
- }
- }
接下来,我们写一个测试页面:
- <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
- <%
- String path = request.getContextPath();
- String basePath = request.getScheme() + "://"
- + request.getServerName() + ":" + request.getServerPort()
- + path + "/";
- %>
- <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
- <html>
- <head>
- <base href="<%=basePath%>">
- <title>secondjsp page</title>
- <meta http-equiv="pragma" content="no-cache">
- <meta http-equiv="cache-control" content="no-cache">
- <meta http-equiv="expires" content="0">
- <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
- <meta http-equiv="description" content="This is my page">
- <link rel="stylesheet" type="text/css" href="../CSS/index.css">
- <script type="text/javascript" src="./js/jquery.js"></script>
- <script type="text/javascript">
- $(document).ready(function() {
- $("#div").hide();
- $("#button").click(function() {
- $("#div").show();
- });
- });
- </script>
- </head>
- <body>
- <%
- String nameString = "小李子";
- String pswdString = "1234567";
- String sexString = "男";
- String ageString = "21";
- /* String nmString = request.getParameter("user");
- String pdString = request.getParameter("pswd");
- String sString = request.getParameter("sex");
- String aString = request.getParameter("age"); */
- /* nameString = new String(nmString.getBytes("ISO-8859-1"), "UTF-8");
- pswdString = new String(pdString.getBytes("ISO-8859-1"), "UTF-8");
- sexString = new String(sString.getBytes("ISO-8859-1"), "UTF-8");
- ageString = new String(aString.getBytes("ISO-8859-1"), "UTF-8"); */
- session.setAttribute("name", nameString);
- session.setAttribute("pswd", pswdString);
- session.setAttribute("sex", sexString);
- session.setAttribute("age", ageString);
- request.setAttribute("name", nameString);
- request.setAttribute("pswd", pswdString);
- request.setAttribute("sex", sexString);
- request.setAttribute("age", ageString);
- pageContext.setAttribute("name", nameString);
- pageContext.setAttribute("pswd", pswdString);
- pageContext.setAttribute("sex", sexString);
- pageContext.setAttribute("age", ageString);
- application.setAttribute("name", nameString);
- application.setAttribute("pswd", pswdString);
- application.setAttribute("sex", sexString);
- application.setAttribute("age", ageString);
- application.setAttribute("name", "123");
- application.setAttribute("pswd", "456");
- application.setAttribute("sex", "女");
- application.setAttribute("age", "25");
- request.setAttribute("name", "123");
- request.setAttribute("pswd", "456");
- request.setAttribute("sex", "女");
- request.setAttribute("age", "25");
- session.setAttribute("name", "123");
- session.setAttribute("pswd", "456");
- session.setAttribute("sex", "女");
- session.setAttribute("age", "25");
- String namepageContextString = (String) pageContext.getAttribute("name");
- String namesessionString = (String) session.getAttribute("name");
- String namerequestString = (String) request.getAttribute("name");
- String nameapplicationString = (String) application.getAttribute("name");
- String pswdpageContextString = (String) pageContext.getAttribute("pswd");
- String pswdsessionString = (String) session.getAttribute("pswd");
- String pswdrequestString = (String) request.getAttribute("pswd");
- String pswdapplicationString = (String) application.getAttribute("pswd");
- String sexpageContextString = (String) pageContext.getAttribute("sex");
- String sexsessionString = (String) session.getAttribute("sex");
- String sexrequestString = (String) request.getAttribute("sex");
- String sexapplicationString = (String) application.getAttribute("sex");
- String agepageContextString = (String) pageContext.getAttribute("age");
- String agesessionString = (String) session.getAttribute("age");
- String agerequestString = (String) request.getAttribute("age");
- String ageapplicationString = (String) application.getAttribute("age");
- %>
- <div align="center">
- <button id="button">点击进行pageContext测试</button>
- <br> <a href="JSP/four.jsp">点击进行session测试</a><br> <b>进行application测试:重启浏览器,并转到此链接:http://localhost:8080/htmlday1/JSP/four.jsp</b>
- </div>
- <div align="center" id="div"
- style="font-family: 楷体;font-size: 25px;color: green;">
- 客户信息:<br> pageContext:<br> 姓名:<%=namepageContextString%><br>
- 密码:<%=pswdpageContextString%><br> 性别:<%=sexpageContextString%><br>
- 年龄:<%=agepageContextString%><br> session:<br> 姓名:<%=namesessionString%><br>
- 密码:<%=pswdsessionString%><br> 性别:<%=sexsessionString%><br>
- 年龄:<%=agesessionString%><br> request:<br> 姓名:<%=namerequestString%><br>
- 密码:<%=pswdrequestString%><br> 性别:<%=sexrequestString%><br>
- 年龄:<%=agerequestString%><br> application:<br> 姓名:<%=nameapplicationString%><br>
- 密码:<%=pswdapplicationString%><br> 性别:<%=sexapplicationString%><br>
- 年龄:<%=ageapplicationString%><br> <a href="JSP/Login.jsp">回到信息输入界面</a>
- </div>
- </body>
- </html>
在这个页面中,我们对request,pageContext,session,application的属性进行设置,修改。
其次还有一个页面,可以帮助我们完成测试:
- <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
- <%
- String path = request.getContextPath();
- String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
- %>
- <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
- <html>
- <head>
- <base href="<%=basePath%>">
- <title>fourjsp page</title>
- <meta http-equiv="pragma" content="no-cache">
- <meta http-equiv="cache-control" content="no-cache">
- <meta http-equiv="expires" content="0">
- <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
- <meta http-equiv="description" content="This is my page">
- <!--
- <link rel="stylesheet" type="text/css" href="styles.css">
- -->
- </head>
- <body>
- <%
- String namepageContextString = (String)pageContext.getAttribute("name");
- String namesessionString = (String)session.getAttribute("name");
- String namerequestString = (String)request.getAttribute("name");
- String nameapplicationString = (String)application.getAttribute("name");
- String pswdpageContextString = (String)pageContext.getAttribute("pswd");
- String pswdsessionString = (String)session.getAttribute("pswd");
- String pswdrequestString = (String)request.getAttribute("pswd");
- String pswdapplicationString = (String)application.getAttribute("pswd");
- String sexpageContextString = (String)pageContext.getAttribute("sex");
- String sexsessionString = (String)session.getAttribute("sex");
- String sexrequestString = (String)request.getAttribute("sex");
- String sexapplicationString = (String)application.getAttribute("sex");
- String agepageContextString = (String)pageContext.getAttribute("age");
- String agesessionString = (String)session.getAttribute("age");
- String agerequestString = (String)request.getAttribute("age");
- String ageapplicationString = (String)application.getAttribute("age");
- %>
- 客户信息:<br>
- pageContext:<br>
- 姓名:<%=namepageContextString %><br>
- 密码:<%=pswdpageContextString %><br>
- 性别:<%=sexpageContextString %><br>
- 年龄:<%=agepageContextString %><br>
- session:<br>
- 姓名:<%=namesessionString %><br>
- 密码:<%=pswdsessionString %><br>
- 性别:<%=sexsessionString %><br>
- 年龄:<%=agesessionString %><br>
- request:<br>
- 姓名:<%=namerequestString %><br>
- 密码:<%=pswdrequestString %><br>
- 性别:<%=sexrequestString %><br>
- 年龄:<%=agerequestString %><br>
- application:<br>
- 姓名:<%=nameapplicationString %><br>
- 密码:<%=pswdapplicationString %><br>
- 性别:<%=sexapplicationString %><br>
- 年龄:<%=ageapplicationString %><br>
- </body>
- </html>
接下来:
因为session并不会在关闭浏览器的时候,及时的销毁session对象,所以,我们在web.xml中进行设置自动销毁时间:
- <session-config>
- <session-timeout>1</session-timeout>
- </session-config>
然后启动项目,对这些事件进行监听:
当服务器开始启动时,就会创建一个application对象,然后服务器对application对象的属性进行操作:
为什么会有一个request对象被销毁呢?
因为浏览器打开有一个首页,但是我们需要浏览器跳转到指定的页面,所以手动的修改了url地址,只要url的地址发生改变,那么,就会产生一个request请求,那么就会有一个request请求被销毁。
因为我们新打开一个浏览器,所以就产生一个新的会话,就会创建一个新的session对象,当我们打开测试的页面时,因为在测试页面里对session,application等进行属性设置,修改,所以:
因为在jsp内部引入了jQuery文件,所以会发生request对象的销毁与新建:
这里是因为,我们设置了session的自动销毁时间是1分钟,所以当超过一分钟的时候,会自动的销毁session,此时如果刷新页面,则会:
到了这里,我们,对3大对象,6个事件八个接口进行了测试,可以检测到application创建销毁的接口,application属性改变的接口,request创建销毁的接口,request属性改变的接口,session创建销毁的接口,session属性改变的接口,以及session的active和Binding的接口事件。
所以,3大对象6种事件8个接口,到了这里就测试完毕了。