显示当前在线人数——监听器listener
显示在线人员列表
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<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>登录页面</title></head><body><form action="loginConf.jsp" method="post"><table><tbody><tr><td><font color="red">${requestScope.error}</font></td></tr><tr><td align="right">用户名:</td><td><input type="text" name="username"/></td></tr><tr><td align="right">密码:</td><td><input type="password" name="password"/></td></tr><tr><td><input type="submit" value="登录"/></td><td><input type="reset" value="重置"/></td></tr></tbody></table></form></body></html>?
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<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>登录判断页面</title></head><body><%String username = request.getParameter("username");// 登录判断省略session.setAttribute("username", username);//将用户名保存到session中%><jsp:forward page="UserList.jsp"></jsp:forward></body></html>?
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<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><%@ page import="java.util.ArrayList" %> <%@ page import="java.util.Iterator" %> <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %><%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>在线人员列表</title></head><body> <h3>在线人员列表</h3> <h5>欢迎${sessionScope.username}的登录，您可以选择<a href="loginOut.jsp">注销</a></h5> <h5>当前总在线人数${fn:length(applicationScope.allUser)}</h5> <c:forEach items="${applicationScope.allUser}" var="username" varStatus="stat"> <img src="images/username.gif"><c:out value="${username}"></c:out> <c:if test="${(stat.index+1)%5==0}"> <br/> </c:if> </c:forEach> </body></html>?
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<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>注销</title></head><body> <% session.invalidate(); %> <jsp:forward page="loginForm.jsp"></jsp:forward></body></html>
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package com.mison.listener;import java.util.ArrayList;import javax.servlet.ServletContext;import javax.servlet.ServletContextEvent;import javax.servlet.ServletContextListener;import javax.servlet.http.HttpSessionAttributeListener;import javax.servlet.http.HttpSessionBindingEvent;import javax.servlet.http.HttpSessionEvent;import javax.servlet.http.HttpSessionListener;public class OnlineUserListListener implements ServletContextListener,HttpSessionListener, HttpSessionAttributeListener {private ServletContext application = null;public void contextInitialized(ServletContextEvent sce) {ArrayList<String> allUser = new ArrayList<String>();application = sce.getServletContext();application.setAttribute("allUser", allUser);}public void contextDestroyed(ServletContextEvent sce) {}public void sessionCreated(HttpSessionEvent se) {}public void sessionDestroyed(HttpSessionEvent se) {ArrayList<String> allUser = (ArrayList<String>) application.getAttribute("allUser");String user = (String) se.getSession().getAttribute("username");allUser.remove(user);application.setAttribute("allUser", allUser);}public void attributeAdded(HttpSessionBindingEvent se) {ArrayList<String> allUser = (ArrayList<String>) application.getAttribute("allUser");String user = (String) se.getValue();allUser.add(user);application.setAttribute("allUser", allUser);}@Overridepublic void attributeRemoved(HttpSessionBindingEvent se) {}@Overridepublic void attributeReplaced(HttpSessionBindingEvent se) {}}?
<?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" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5"><listener> <description>在线人数监听器</description> <listener-class>com.mison.listener.OnlineUserListListener</listener-class> </listener> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list></web-app>