监视在线用户数<测试通过>
创建监听器：OnlineListener.java
package com.Sourcecode.SessionFactory;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;
public class OnlineListener implements HttpSessionListener
{
private int count;
public OnlineListener()
{
count = 0;
}
public void sessionCreated(HttpSessionEvent sessionEvent)
{
count++;
sessionEvent.getSession().setAttribute("online", new Integer(count));
}
public void sessionDestroyed(HttpSessionEvent sessionEvent)
{
count--;
sessionEvent.getSession().setAttribute("online", new Integer(count));
}
}
监听器在web.xml中的配置
<listener>
<listener-class>com.Sourcecode.SessionFactory.OnlineListener</listener-class>
</listener>
页面测试online.jsp
<%@ page language="java" pageEncoding="UTF-8"%>
<html>
<head>
</head>
<body>
<h2>
当前在线人数:<%=(Integer) session.getAttribute("online")%></h2>
</body>
</html>
