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
时间： 2024-10-19 12:11:18