jsp 统计在线人数

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">
****************************************
<!-- Listeners -->
<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>


看看可以实现不?我也是找到的,我用了,可以统计出来.

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