主页面

需要登录才能进入，所以需要设置一个登录拦截的功能

//获取session作用域中的数据

Object obj = session.getAttribute(“loginUser”);

if(obj==null){

//没有登录，进入登录页面

response.sendRedirect(“login.jsp”);

return;//结束这个页面

}

  1. <%@ page contentType="text/html;charset=UTF-8" language="java" %>
  2. <%@page import="com.mt.pojo.User" %>
  3. <%
  4.     //获取session作用域中的数据
  5.     Object obj = session.getAttribute("loginUser");
  6.     if(obj==null){
  7.         //没有登录，进入登录页面
  8.         response.sendRedirect("login.jsp");
  9.         return;//结束这个页面
  10.     }
  11. %>
  12. <html>
  13. <head>
  14.     <title>主页</title>
  15. </head>
  16. <body>
  17. <h1>后台管理的主页</h1>
  18. <h2>欢迎[<%=((User)obj).getUname()%>]</h2>
  19. </body>
  20. </html>

servlet

  1. 做一个登录的servlet,在登录的时候做一个查询用户，找到用户并且验证成功以后将用户添加到session作用域，重定向到主页面。如果验证失败就返回到登录界面；
  1. /**
  2.  * @author:刘倩云
  3.  * @createTime:2021-02-25
  4.  */
  5. public class LoginServlet extends HttpServlet {
  6.     @Override
  7.     protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
  8.         this.doPost(req,resp);
  9.     }
  10.     @Override
  11.     protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
  12.         //获取请求参数
  13.         String uname = req.getParameter("uname");
  14.         String password = req.getParameter("password");
  15.         String remember = req.getParameter("remember");
  17.         //获取用户
  18.         User user = UserData.queryUserByName(uname);
  19.         if(user!=null&&user.getPassword().equals(password)){
  20.             //登录成功
  21.             //获取session
  22.             HttpSession session = req.getSession();
  23.             //将用户对象信息放入session的作用域
  24.             session.setAttribute("loginUser",user);
  25.             //直接进入主页面
  26.             resp.sendRedirect("main");
  27.         }else {
  28.             resp.sendRedirect("login.jsp");
  29.         }
  30.     }
  31. }

登录页面

  1. <%@ page contentType="text/html;charset=UTF-8" language="java" %>
  2. <html>
  3. <head>
  4.     <meta charset="UTF-8">
  5.     <title>用户登录</title>
  6.     <link rel="stylesheet" href="https://cdn.staticfile.org/twitter-bootstrap/4.3.1/css/bootstrap.min.css">
  7.     <script src="https://cdn.staticfile.org/jquery/3.2.1/jquery.min.js"></script>
  8.     <script src="https://cdn.staticfile.org/popper.js/1.15.0/umd/popper.min.js"></script>
  9.     <script src="https://cdn.staticfile.org/twitter-bootstrap/4.3.1/js/bootstrap.min.js"></script>
  10.     <style>
  11.         form{
  12.             margin: 0 auto;
  13.             margin-top: 100px;
  14.             width: 350px;
  15.         }
  17.     </style>
  18. </head>
  19. <%--判断客户端是否有数据--%>
  20. <%
  21.     String uname = "";
  22.     String utoken = "";
  23.     //获取cookie
  24.     Cookie[] cookies = request.getCookies();
  25.     if(cookies!=null){
  26.         for(Cookie cookie:cookies){
  27.             if(cookie.getName().equals("uname")){
  28.                 uname = cookie.getValue();//记录在客户端的用户名
  29.             }
  30.             if(cookie.getName().equals("utoken")){
  31.                 utoken = cookie.getValue();//记录在客户端的token
  32.             }
  33.         }
  34.     }
  35. %>
  36. <body>
  37. <div class="container">
  38.     <form action="login" method="post">
  39.         <div class="form-group">
  40.             <label for="uname">用户名:</label>
  41.             <input type="text" class="form-control" name="uname" id="uname" placeholder="用户名">
  42.         </div>
  43.         <div class="form-group">
  44.             <label for="pwd">密码：</label>
  45.             <input type="password" class="form-control" name="password" id="pwd" placeholder="密码">
  46.         </div>
  47.         <div class="form-check">
  48.             <label class="form-check-label">
  49.                 <input class="form-check-input" type="checkbox" name="remember" value="1"> 记住密码
  50.             </label>
  51.         </div>
  52.         <button type="submit" class="btn btn-primary">登录</button>
  53.     </form>
  54. </div>
  55. </body>
  56. </html>

用户数据

  1. /**
  2.  * @author:刘倩云
  3.  * @createTime:2021-02-25
  4.  */
  5. public class UserData {
  6.     private static List<User> users = new ArrayList<>();
  8.     static {
  9.         addUser(new User("admin","123456",""));
  10.         addUser(new User("xiaoliu","123456",""));
  11.         addUser(new User("xiaowang","123456",""));
  12.         addUser(new User("haha","123456",""));
  13.         addUser(new User("Cherry","123456",""));
  14.         addUser(new User("Tracer","123456",""));
  15.     }
  16.     //添加用户
  17.     public static void addUser(User user){
  18.         users.add(user);
  19.     }
  21.     //通过用户名查找
  22.     public static User queryUserByName(String name){
  23.         //遍历集合
  24.         for(User user:users){
  25.             if(user.getUname().equals(name)){
  26.                 return user;
  27.             }
  28.         }
  29.         return null;
  30.     }
  31. }