servlet监听器统计在线人数

1.登录用户信息类
import java.util.Vector;

public class UserInfoList {

    private static UserInfoList user = new UserInfoList();
    private Vector vector = null;

    public UserInfoList() {
        this.vector = new Vector();
    }

    public static UserInfoList getInstance() {
        return user;
    }

    public boolean addUserInfoList(String user) {
        if (user != null) {
            this.vector.add(user);
            return true;
        } else {
            return false;
        }
    }

    public Vector getList() {
        return this.vector;
    }

    public void removeUserInfo(String user) {
        if (user != null) {
            vector.removeElement(user);
        }
    }
}
public class UserInfoList

2.监听器类

import javax.servlet.http.HttpSessionBindingEvent;
import javax.servlet.http.HttpSessionBindingListener;

import com.fmz.UserInfoList;

public class UserInfoTrace implements HttpSessionBindingListener {

    private String user;
    private UserInfoList container = UserInfoList.getInstance();

    public UserInfoTrace() {
        user = "";
    }

    public void setUser(String user) {
        this.user = user;
    }

    public String getUser() {
        return this.user;
    }

    public void valueBound(HttpSessionBindingEvent arg0) {
        System.out.println("上线" + this.user);
    }

    @Override
    public void valueUnbound(HttpSessionBindingEvent arg0) {
        System.out.println("下线" + this.user);
        if (user != null) {
            container.removeUserInfo(user);
        }
    }

}
UserInfoTrace implements HttpSessionBindingListener

3.后台show.jsp

<%@page import="java.util.Vector"%>
<%@page import="com.listener.UserInfoTrace"%>
<%@page import="com.fmz.UserInfoList"%>
<%@ page language="java" pageEncoding="UTF-8"%>
<!doctype html>
<html lang="zh-CN">
<head>
<meta charset="UTF-8" />
<title>showUser</title>
</head>
<body>
<%
    UserInfoList list = UserInfoList.getInstance();
    UserInfoTrace ut = new UserInfoTrace();
    String name = request.getParameter("name");
    ut.setUser(name);
    session.setAttribute("list", ut);
    list.addUserInfoList(ut.getUser());
    session.setMaxInactiveInterval(10);
%>
<textarea rows="8" cols="20">
<%
    Vector vector = list.getList();
    if (vector != null && vector.size() > 0) {
        for (int i = 0; i < vector.size(); i++) {
            out.println(vector.elementAt(i));
        }
    }
%>
</textarea>
</body>
</html>
show.jsp

测试：index.jsp（show.jsp页面显示的中文乱码未解决）

<%@ page language="java" pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<title>index</title>
<style>
input,p{
margin: 5px;
padding: 3px;
}
</style>
</head>
<body>
    <form action="showUser.jsp" method="post" align="center">
        nickname: <input type="text" name="name"><br> password:
        <input type="submit" value="submit" style="margin-left:100px "><br>
    </form>
    
</body>
</html>
test

 

posted @ 2017-08-16 09:53  fie  Views(687)  Comments(0)  Edit  收藏  举报