JSP统计在线人数

SessionCounter.java
==============
package SessionCount;
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;
 }
}
 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
</listener-class>
...............
</listener>
</web-app>
===============
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:<%=SessionCounter.getActiveSessions()%>
    </body>

</html>



my 2007-04-09 15:12 发表评论

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