Javaweb实现在线人数统计代码实例

package com.my.count;
import javax.servlet.http.*;
public class SessionCounter implements HttpSessionListener {

  private static int activeSessiOns= 0;
  //session创建时执行
  public void sessionCreated(HttpSessionEvent se) {
    activeSessions++;
  }
  //session销毁时执行
  public void sessionDestroyed(HttpSessionEvent se) {
    if (activeSessions > 0)
      activeSessions--;
  }
  //获取活动的session个数(在线人数)
  public static int getActiveSessions() {
    return activeSessions;
  }
}

   
     com.my.count.SessionCounter //这里是包名加类名
   
 

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ page import="com.my.count.SessionCounter"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>



 
  
  
  
  
  
  
    
  
  
  

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

package com.wangyun.web.controllers;

import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;

public class SessionCounter implements HttpSessionListener {

   static int activeSessiOns= 0;
  //session创建时执行
  public void sessionCreated(HttpSessionEvent se) {
    activeSessions++;
  }
  //session销毁时执行
  public void sessionDestroyed(HttpSessionEvent se) {
    if (activeSessions > 0)
      activeSessions--;
  }
  //获取活动的session个数(在线人数)
  public static int getActiveSessions() {
    return activeSessions;
  }

}

  /**
 	 * 在线用户人数
 	 * @throws IOException 
 	 * @throws ServletException 
 	 */
   @RequestMapping(value="user_online", method=RequestMethod.POST, produces="text/json;charset=utf-8")
 	@ResponseBody
 	public Object user_online() throws ServletException, IOException {
 			JSONObject data = new JSONObject();
 			int number=SessionCounter.activeSessions;
 			data.put("msg",number);
 			return data.toString();
   }