jsp教程 利用application统计在线人数代码
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>application</title>
</head>
<body>
<%!
Integer number;//
synchronized void numberVisiter()
{
ServletContext application = getServletContext();
Integer num = (Integer)application.getAttribute("count");
if(num == null)//如果是第一个访问者
{
num = new Integer(1);
application.setAttribute("count",num);
}
else
{
num = new Integer(num.intValue() + 1);
application.setAttribute("count",num);
}
}
%>
<%
if(session.isNew())
{
numberVisiter();
Integer number = (Integer)application.getAttribute("count");
}
%>
<p>
<font size="2" color="blue">简单的页面访问计数器</font>
</p>
<p>
<font size="2" color="#000000">
欢迎访问此页面，您是<%=number%>个访问用户
</font>
</p>
</body>
</html>