本文实例为大家分享了Javaweb统计在线人数示的具体代码，供大家参考，具体内容如下
1. 实现功能
统计在线人数
显示每个人的sessionId、Ip、第一次登录时间
2. 运用监听器种类
3. 实现思想
4. 包目录
5. 代码实现
User
package entity;public class User { private String sessionID; private String ip; private String firstTime; public String getSessionID() { return sessionID; } public void setSessionID(String sessionID) { this.sessionID = sessionID; } public String getIp() { return ip; } public void setIp(String ip) { this.ip = ip; } public String getFirstTime() { return firstTime; } public void setFirstTime(String firstTime) { this.firstTime = firstTime; }}MyHttpSessionListener
package listenner;import java.util.ArrayList;import javax.servlet.annotation.WebListener;import javax.servlet.http.HttpSessionEvent;import javax.servlet.http.HttpSessionListener;import entity.User;import util.SessionUtil;@WebListenerpublic class MyHttpSessionListener implements HttpSessionListener { private int num = 0;//统计人数 public void sessionCreated(HttpSessionEvent se) { num++; se.getSession().getServletContext().setAttribute("number", num); } @SuppressWarnings("unchecked") public void sessionDestroyed(HttpSessionEvent se) { num--; se.getSession().getServletContext().setAttribute("number", num); //在此用户被销毁的时候，将链表中对应的用户对象删除 ArrayList<User> userlist = (ArrayList<User>) se.getSession().getServletContext().getAttribute("userlist"); if (SessionUtil.getUserBySessionID(userlist, se.getSession().getId()) != null) { userlist.remove(SessionUtil.getUserBySessionID(userlist, se.getSession().getId())); } }}MyServeltRequestListener
package listenner;import java.text.SimpleDateFormat;import java.util.ArrayList;import java.util.Date;import javax.servlet.ServletRequestEvent;import javax.servlet.ServletRequestListener;import javax.servlet.annotation.WebListener;import javax.servlet.http.HttpServletRequest;import entity.User;import util.SessionUtil;@WebListenerpublic class MyServeltRequestListener implements ServletRequestListener { @SuppressWarnings("unchecked") public void requestInitialized(ServletRequestEvent sre) { ArrayList<User> userlist=null; //获取全局变量中的链表，若不存在，则创建一个新的链表 userlist= (ArrayList<User>) sre.getServletContext().getAttribute("userlist"); if (userlist == null) { userlist = new ArrayList<User>(); } //获取request对象 HttpServletRequest request = (HttpServletRequest) sre.getServletRequest(); //获取sessionID String sessionID = request.getSession().getId(); //通过sessionID在链表中查找对象，若没有此对象，则创建加入到链表中 if (SessionUtil.getUserBySessionID(userlist, sessionID) == null) { User user = new User(); user.setSessionID(sessionID); user.setFirstTime(new SimpleDateFormat("YYYY-MM-DD hh:mm:ss").format(new Date())); user.setIp(request.getRemoteAddr()); userlist.add(user); } //将链表设置为全局变量 sre.getServletContext().setAttribute("userlist", userlist); }}getUserBySessionID
package util;import java.util.ArrayList;import entity.User;public class SessionUtil { //工具类，通过session在链表中找到相应的用户对象 public static User getUserBySessionID(ArrayList<User> userlist, String sessionID) { for (int i = 0; i < userlist.size(); i++) { User user=userlist.get(i); if (user.getSessionID().equals(sessionID)){ return user; } } return null; }}index.jsp
<%@page import="entity.User"%><%@page import="java.util.ArrayList"%><%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><title></title></head><body> 当前在线人数:${number} <hr> <% ArrayList<User> userlist = (ArrayList<User>) request.getServletContext().getAttribute("userlist"); if (userlist != null) { for (int i = 0; i < userlist.size(); i++) { User user = userlist.get(i); %> sessionID：<%=user.getSessionID()%> <br> IP:<%=user.getIp()%> <br> FirstName:<%=user.getFirstTime()%> <hr> <%}}%></body></html>以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持武林网。
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