jsp统计在线人数代码

关注+2011-05-17作者：不详

首先写个类:

    import javax.servlet.*;

    import javax.servlet.http.*;

    public class SessionCounter implements HttpSessionListener {

    private static int activeSessions = 0;

    public void sessionCreated(HttpSessionEvent se) {

    activeSessions++;

    }

    public void sessionDestroyed(HttpSessionEvent se) {

    if(activeSessions > 0)

    activeSessions--;

    }

    public static int getActiveSessions() {

    return activeSessions;

    }

    }

    然后配置web.xml



    <?xml version="1.0" encoding="UTF-8"?>

    <web-app version="2.4"

    xmlns="http://java.sun.com/xml/ns/j2ee"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee

    http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

    ****************************************

    

    <listener>

    <listener-class>

    SessionCount.SessionCounter (注意此处)

    </listener-class>

    </listener>

    *****************************************

    </web-app>

  建个JSP测试:

    test.jsp

    <%@ page language="Java" contentType="text/html;charset=GBK"%>

    <%@ page import="java.sql.*"%>

    <%@ page import="SessionCount.SessionCounter" %>

    <html>

    <head>

    <meta http-equiv="Content-Type" content="text/html; charset=GBK">

    <title>无标题文档</title>

    <body bgcolor="#FFFFFF">

    在线人数:<%=SessionCounter.getActiveSessions()%>

    </body>

    </html>

     测试以下，会发现程序已经统计出结果了。