//登录页面 login.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <script type="text/javascript" src="./js/jquery-3.5.1.min.js"></script> <script type="text/javascript" src="./js/vue.js"></script> <title>登录</title> <% String msg = (String)(request.getAttribute("msg")==null?"":request.getAttribute("msg")); %> <script type="text/javascript"> function show(){ if('<%=msg%>'!=''){ alert('<%=msg%>'); } } </script> </head> <body style="text-align: center" οnlοad="show();"> <form action="${pageContext.request.contextPath}/login.do" method="post"> <table border="1"> <tr> <td align="center" colspan="2"> <h3>用户登录</h3> </td> </tr> <tr> <td align="right"> 用户名 </td> <td align="left"> <input type="text" id="userName" name="userName"> </td> </tr> <tr> <td align="right"> 密 码 </td> <td align="left"> <input type="password" id="password" name="password"> </td> </tr> <tr> <td align="center" colspan="2"> <input type="submit" value="登录"> <input type="reset" value="重置"> </td> </tr> </table> </form> </body> </html>
//主页面 main.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>登录成功</title>
<script type="text/javascript" src="./js/jquery-3.5.1.min.js"></script>
<script type="text/javascript" src="./js/vue.js"></script>
</head>
<%
response.setHeader("Pragma","No-cache");
response.setHeader("Cache-Control","No-cache");
response.setDateHeader("Expires", -1);
response.setHeader("Cache-Control", "No-store");
String userName = "";
userName = (String)(session.getAttribute("userName")==null?"":session.getAttribute("userName"));
%>
<script type="text/javascript">
var count;
var userMsg = '';
var i =0;
function checkUserOnline(){
$.ajax({
type:"post",
url:"${pageContext.request.contextPath}/checkUserOnline.do",
dataType : "text",
success:function(data){
userMsg = data;
//alert(JSON.stringify(userMsg))
},
error:function(){
alert("获取用户信息失败！");
clearInterval(count);
reLogin();
}
});
if(userMsg=='null'||userMsg==''|| userMsg == 'undefined'){
return;
}else{
//alert(JSON.stringify(userMsg));
clearInterval(count);
reLogin();
}
}
function reLogin(){
window.location = "login.jsp";
}
function checkLogin(){
alert("检查");
count = setInterval("checkUserOnline()",5000);
}
</script>
<body onclick="checkLogin()">
<%
if(!"".equals(userName)){
out.print("登陆成功！<br/>用户名：<span id='userName'>"+userName+"</span><br/><input type='button' value='重新登陆' οnclick='reLogin();'/>");
}
%>
</body>
</html>
//控制类 LoginController
package com.zjn.oneLogin.dengLu;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
@Controller
public class LoginController{
/**
* 用户和Session绑定关系
*/
public static final Map<String, HttpSession> USER_SESSION = new HashMap<String, HttpSession>();
/**
* seeionId和用户的绑定关系
*/
public static final Map<String, String> SESSIONID_USER = new HashMap<String, String>();
@RequestMapping("/login")
@ResponseBody
public Map<String,Object>toLogin(HttpServletRequest request, HttpServletResponse response) throws Exception{
//获取请求命令
request.setCharacterEncoding("utf-8");
String servletPath = request.getServletPath();//获取请求路径
String uri = servletPath.substring(1, servletPath.lastIndexOf(".do"));
try{
//登录
if ("login".equals(uri)){
HttpSession session = request.getSession();
String userName = request.getParameter("userName");
String password = request.getParameter("password");
if (userName != null && !"".equals(userName.trim())){
//登录成功
if (login(userName, password)){
//处理用户登录(保持同一时间同一账号只能在一处登录)
userLoginHandle(request);
//添加用户与HttpSession的绑定
USER_SESSION.put(userName.trim(), session);
//添加sessionId和用户的绑定
SESSIONID_USER.put(session.getId(), userName);
System.out.println("添加sessionId和用户的绑定 ==="+session.getId());
System.out.println("用户[" + userName + "] 已上线...");
session.setAttribute("userName", userName);
session.removeAttribute("userMsg");//从session中移除用户信息
//重定向到首页
response.sendRedirect("main.jsp");
}
//登录失败
else{
System.out.println("用户[" + userName + "] 登录失败...");
request.setAttribute("msg", "登录失败，请重新登录！");
//response.sendRedirect("login.jsp");
request.getRequestDispatcher("login.jsp").forward(request, response);
}
}
else{
System.out.println("用户[" + userName + "] 登录失败...");
request.setAttribute("msg", "登录失败，请重新登录！");
//response.sendRedirect("login.jsp");
request.getRequestDispatcher("login.jsp").forward(request, response);//跳转到用户页面，返回请求响应对象
}
}else if ("reLogin".equals(uri)){
//重新登陆
HttpSession session = request.getSession();
String userName = (String)session.getAttribute("userName");
if (session != null){
//销毁相关session
//USER_SESSION.remove(SESSIONID_USER.remove(session.getId()));
session.invalidate();
}
if (userName != null && !"".equals(userName)){
System.out.println("用户[" + userName + "] 已下线...");
}
//重定向到登录页面
response.sendRedirect("login.jsp");
}
}
catch (Exception e){
System.out.println(e.getClass() + e.getMessage());
PrintWriter out = response.getWriter();
out.print("服务器内部错误！");
}
return null;
}
/**
*
* Description:用户登录时的处理 <br>
* @param request
* @see
*/
private void userLoginHandle(HttpServletRequest request){
//当前登录的用户
String userName = request.getParameter("userName");
System.out.println("userName=="+userName);
//当前sessionId
//String sessionId = request.getSession().getId();
//删除当前sessionId绑定的用户，用户--HttpSession
//USER_SESSION.remove(SESSIONID_USER.remove(sessionId));
//删除当前登录用户已绑定的HttpSession
HttpSession session = USER_SESSION.remove(userName);//map中的remove方法返回删除value值
if (session != null){
//删除已登录的sessionId绑定的用户
SESSIONID_USER.remove(session.getId());
session.removeAttribute("userName");
session.setAttribute("userMsg", "您的账号已经在另一处登录，您被迫下线！");
}
}
/**
*
* Description: 模拟DB登录判断<br>
* @param userName 用户
* @param password 密码
* @return
* @see
*/
private boolean login(String userName, String password){
return ("peizhongxian".equals(userName) && "123456".equals(password));
}
/**
* 判断用户是否同时登陆同一个用户
*
* */
@RequestMapping(value="/checkUserOnline")
@ResponseBody
public void checkUserOnline(HttpServletRequest request,HttpServletResponse response) throws IOException{
HttpSession session=request.getSession();
PrintWriter out = response.getWriter();
out.print(session.getAttribute("userMsg"));
}
}
//监听器 MyListener
package com.zjn.oneLogin.dengLu;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;
public class MyListener implements HttpSessionListener {
/**
* 实现HttpSessionListener接口监听 监听session的创建事件
*/
public void sessionCreated(HttpSessionEvent se){
String sessionId = se.getSession().getId();
System.out.println("创建session sessionId= " + sessionId);
}
/**
* 实现HttpSessionListener接口监听 监听session的销毁事件
*/
public void sessionDestroyed(HttpSessionEvent se){
String sessionId = se.getSession().getId();
System.out.println("sessionId========="+sessionId);
//当前session销毁时删除当前session绑定的用户信息
//同时删除当前session绑定用户的HttpSession
LoginController.USER_SESSION.remove(LoginController.SESSIONID_USER.remove(sessionId));
System.out.println("销毁session sessionId= " + sessionId);
}
}
//web.xml 文件
<listener> <listener-class>com.zjn.oneLogin.dengLu.MyListener</listener-class> </listener>