JavaWeb-Listener2-在线用户统计

来源：互联网发布：淘宝乔丹是真的吗编辑：程序博客网时间：2024/04/29 18:19

话说：

各位读者，早安！前面专门有一篇博客介绍Listener的，这篇来点好玩的。

我们要实现的功能是这样的：一尊贵的来宾来访问enter.jsp,登陆后，跳转到online.jsp，页面显示来宾姓名和在线人数；因为我们用的是HttpSessionBindingListener，所以我们用不同浏览器访问测试：
目的很简单，也是运用一下监听器喽。

这里写图片描述

这里用的是360先测试，一会用专业浏览器谷歌哈。
以下是这个玩耍过程的整体布局：

这里写图片描述

先上三个页面：

enter.jsp

<%--  User: Meice  Date: 2017/10/9  Time: 23:23--%><%@ page contentType="text/html;charset=UTF-8" language="java" %><html><head>    <title>Title</title></head><body>    <form action="login.do" method="post">        来宾名：<input  type="text" name="gustName"/><br/>        <input type="submit" value="进入">    </form></body></html>

online.jsp

<%@ page import="com.hmc.listener.util.OnLineUtil" %><%--  User: Meice  Date: 2017/10/10  Time: 8:07--%><%@ page contentType="text/html;charset=UTF-8" language="java" %><html><head>    <title>统计在线人数</title>    <%     String username =   request.getParameter("username");    %></head><body>   <h2>您好： ${user.name}</h2>    <h2>此时的在线人数为：<%=OnLineUtil.ONLINE_COUNT %> <br/></h2>    <a href="loginOut.do">离开</a></body></html>

User
这个实体类，用来实现HttpSessionListener接口，实现登陆用户在线统计，是这里面最核心的功能

package com.hmc.listener.model;import com.hmc.listener.util.OnLineUtil;import javax.servlet.http.HttpSessionBindingEvent;import javax.servlet.http.HttpSessionBindingListener;/** * User:Meice * 2017/10/11 */public class User implements HttpSessionBindingListener {    private String name;    public User() {}    public User(String name) {        this.name = name;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    @Override    public void valueBound(HttpSessionBindingEvent httpSessionBindingEvent)    {        OnLineUtil.ONLINE_COUNT++;    }    @Override    public void valueUnbound(HttpSessionBindingEvent httpSessionBindingEvent) {        OnLineUtil.ONLINE_COUNT--;    }}

LoginServlet
用户登陆后，接收参数并实现页面跳转

package com.hmc.listener.servlet;import com.hmc.listener.model.User;import javax.servlet.ServletException;import javax.servlet.annotation.WebFilter;import javax.servlet.annotation.WebInitParam;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.IOException;/** * User:Meice * 2017/10/11 *///@WebFilter(urlPatterns = "/*",//        initParams = {//                @WebInitParam(name = "encoding",value = "UTF-8")//        })@WebServlet(urlPatterns = "/login.do")public class LoginServlet extends HttpServlet {    @Override    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {        doPost(req,resp);    }    @Override    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {        //接收参数        String gustName =  req.getParameter("gustName");        //实例化User        User user = new User(gustName);         req.getSession().setAttribute("user",user);        //页面跳转        resp.sendRedirect("online.jsp");    }}

LoginOutServlet
功能：点击离开，实现用户销毁

package com.hmc.listener.servlet;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.IOException;/** * User:Meice * 2017/10/11 */@WebServlet(urlPatterns = "/loginOut.do")public class LoginOutServlet extends HttpServlet {    @Override    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {        doPost(req,resp);    }    @Override    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {       //销毁session        req.getSession().invalidate();        resp.sendRedirect("enter.jsp");    }}

OnLineUtil

就是用户统计的一个常量存放

package com.hmc.listener.util;/** * User:Meice * 2017/10/11 */public class OnLineUtil {    //为便于调用且数量开始是常量所以定义为static    public static int ONLINE_COUNT=0;}

结果是这样的：

这里写图片描述

原谅我没有更多的浏览器了。。。。。。
如果让很多人访问，场面一定很壮观！OK，到这里吧。下期再见！

阅读全文

0 0