1、第一次訪問，登錄成功
(1)登陸界面
<%@ 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="jquery-3.2.1/jquery-3.2.1.min.js"></script>
<script type="text/javascript">
function login() {
var userInfo = {
"uname":$("#userName").val(),
"upsw":$("#userPwd").val()
};
$.getJSON("UserLoginServlet.action",userInfo,function(data){
if(data.success){
//需要完善
window.location.href = "${pageContext.request.contextPath}/HouseInfoShowServlet.action";
}else{
alert("用戶名或密碼錯誤，請重新輸入");
$("#userName").focus();
}
});
}
</script>
<title>Insert title here</title>
</head>
<body>
<div>
<input type="text" id="userName"/><br/>
<input type="password" id="userPwd"/><br/>
<button onclick="login()">登錄</button>
</div>
</body>
</html>
2、根據用戶名和密碼檢查是否有該session，如果有session中存入已登錄信息，覆蓋session
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
String name=request.getParameter("Userame");
String password=request.getParameter("password");
System.out.println(name);
System.out.println(password);
//List<UserInfo> lists = Methods.selectNamePwd();
UserInfo info = Methods.selectNamePwd(name, password);
ResultMsg result;
if(info!=null) {
checkUser(request);
info.setUserName(name);
HttpSession session = request.getSession();
session.setAttribute("info", info);
response.sendRedirect("HouseShow.action");
result = ResultMsg.success();
}else{
result = ResultMsg.failure("輸入的密碼不正確！請查證！");
request.getRequestDispatcher("login.html").forward(request, response);
}
response.getWriter().write(JSON.toJSONString(result));
/*for(UserInfo s2:lists) {
String name1 = s2.getUserName();
String password2 = s2.getUserPwd();
if(name.equals(name1)&&password.equals(password2)) {
response.sendRedirect("HouseShow");
}else {
request.getRequestDispatcher("login.html");
}
}*/
}
3、如果沒有添加session
private void checkUser(HttpServletRequest request) {
String userName = request.getParameter("Userame");
String userPwd = request.getParameter("password");
//獲取上次登錄的session(如果有的話)
HttpSession session = SessionInfo.USER_SESSION.get(userName+userPwd);
if(session!=null) {
//在上次登錄的session中放入一條信息
session.setAttribute("msg", ResultMsg.failure("該賬號在另一處登錄，是否重新登錄"));
}
//此處有替換session的功能
SessionInfo.USER_SESSION.put(userName+userPwd, request.getSession());
}
4、跳轉到data.jsp界面
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
HttpSession session = request.getSession();
UserInfo info = (UserInfo) session.getAttribute("info");
System.out.println(info.getUserName());
String userName = info.getUserName();
List<HouseInfo> houseInfos = Methods.selectHouse(userName);
session.setAttribute("houseInfos",houseInfos);
request.getRequestDispatcher("/WEB-INF/data.jsp").forward(request, response);
5、在該界面中循環訪問checkLogin，獲取信息
$(function() {
setInterval(checkUserOnline, 5*1000);
});
function checkUserOnline() {
$.getJSON("UserCheckLoginServlet.action",function(data){
if(!data.success){
alert(data.msg);
//註銷
window.location.href = "${pageContext.request.contextPath}/UserLogoutServlet.action";
}
});
}
6、如果發現已登錄，跳轉到註銷servlet中
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("application/json");
ResultMsg msg = (ResultMsg) request.getSession().getAttribute("msg");
//表示未出現重複登錄情況
if(msg == null) {
msg = ResultMsg.success();
}
response.getWriter().write(JSON.toJSONString(msg));
}
6、在註銷servlet中，使session實效，跳轉到login.jsp
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//註銷以後把 對象移除
HttpSession session = request.getSession();
UserInfo userInfo = (UserInfo) session.getAttribute("info");
if(session == SessionInfo.USER_SESSION.get(userInfo.getUserName()+userInfo.getUserPwd())) {
SessionInfo.USER_SESSION.remove(userInfo.getUserName()+userInfo.getUserPwd());
}
//移除session
session.invalidate();
//重定向到登錄頁面login.jsp
response.sendRedirect(request.getContextPath()+"/login.html");
}