利用session完成用户登陆

 1 package cn.itcast.cookie;
 2 
 3 import java.io.IOException;
 4 import java.io.PrintWriter;
 5 import java.util.List;
 6 
 7 import javax.servlet.ServletException;
 8 import javax.servlet.http.Cookie;
 9 import javax.servlet.http.HttpServlet;
10 import javax.servlet.http.HttpServletRequest;
11 import javax.servlet.http.HttpServletResponse;
12 import javax.servlet.http.HttpSession;
13 
14 import cn.itcast.Db;
15 import cn.itcast.Db1;
16 import cn.itcast.User;
17 
18 public class SessionDemo extends HttpServlet {
19 
20     public void doGet(HttpServletRequest request, HttpServletResponse response)
21             throws ServletException, IOException {
22         
23         response.setCharacterEncoding("UTF-8");
24         response.setContentType("text/html;charset=UTF-8");
25         PrintWriter out = response.getWriter();
26         
27         String username = request.getParameter("username");
28         String password = request.getParameter("password");
29 
30         List<User> list = Db1.getAll();
31         for (User user : list) {
32             if(user.getUsername().equals(username)&&user.getPassword().equals(password)){
33                 request.getSession().setAttribute("user", user);//登录成功，向session存入一个登录标记
34                 response.sendRedirect("/ServletDemo/index.jsp");
35                 return;
36             }
37         }
38         
39         out.write("用户名或密码错误！");
40     }
41 
42     public void doPost(HttpServletRequest request, HttpServletResponse response)
43             throws ServletException, IOException {
44 
45     }
46 
47 }

 1 package cn.itcast.cookie;
 2 
 3 import java.io.IOException;
 4 import java.io.PrintWriter;
 5 
 6 import javax.servlet.ServletException;
 7 import javax.servlet.http.HttpServlet;
 8 import javax.servlet.http.HttpServletRequest;
 9 import javax.servlet.http.HttpServletResponse;
10 import javax.servlet.http.HttpSession;
11 
12 //完成任务注销
13 public class SessionDemo2 extends HttpServlet {
14 
15     
16     public void doGet(HttpServletRequest request, HttpServletResponse response)
17             throws ServletException, IOException {
18 
19         response.setCharacterEncoding("UTF-8");
20         response.setContentType("text/html;charset=UTF-8");
21         PrintWriter out = response.getWriter();
22         
23         HttpSession session = request.getSession();
24         if(session==null){
25             response.sendRedirect("/ServletDemo/index.jsp");
26             return;
27         }
28         
29         session.removeAttribute("user");
30         response.sendRedirect("/ServletDemo/index.jsp");
31         
32     }
33 
34     
35     public void doPost(HttpServletRequest request, HttpServletResponse response)
36             throws ServletException, IOException {
37 
38         
39     }
40 
41 }

 1 package cn.itcast;
 2 
 3 import java.util.ArrayList;
 4 import java.util.List;
 5 
 6 public class Db1 {
 7     
 8     public static List list = new ArrayList();
 9     static{
10         list.add(new User("aaa","123"));
11         list.add(new User("bbb","123"));
12         list.add(new User("ccc","123"));
13         list.add(new User("ddd","123"));
14     }
15     
16     public static List getAll(){
17         return list;
18     }
19 
20 }

 1 package cn.itcast;
 2 
 3 public class User {
 4     private String username;
 5     
 6     public User() {
 7         super();
 8     }
 9 
10     public User(String username, String password) {
11         super();
12         this.username = username;
13         this.password = password;
14     }
15 
16     private String password;
17 
18     public String getUsername() {
19         return username;
20     }
21 
22     public void setUsername(String username) {
23         this.username = username;
24     }
25 
26     public String getPassword() {
27         return password;
28     }
29 
30     public void setPassword(String password) {
31         this.password = password;
32     }
33 
34 }

 1 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
 2 <%
 3 String path = request.getContextPath();
 4 String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
 5 %>
 6 
 7 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
 8 <html>
 9   <head>
10     <base href="<%=basePath%>">
11     
12     <title>My JSP ‘index.jsp‘ starting page</title>
13     <meta http-equiv="pragma" content="no-cache">
14     <meta http-equiv="cache-control" content="no-cache">
15     <meta http-equiv="expires" content="0">    
16     <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
17     <meta http-equiv="description" content="This is my page">
18     <!--
19     <link rel="stylesheet" type="text/css" href="styles.css">
20     -->
21   </head>
22   
23   <body>
24     欢迎您：${user.username }<a href="/ServletDemo/register.html">登录</a> <a href="/ServletDemo/servlet/SessionDemo2">退出登录</a>
25   </body>
26 </html>

 1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
 2 <html>
 3     <head>
 4         <title>register.html</title>
 5 
 6     </head>
 7     
 8     <style>
 9     </style>
10 
11     <body>
12         <form action="/ServletDemo/servlet/SessionDemo" method="get">
13         用户名：
14         <input type="text" name="username">
15         <br />
16         密码：
17         <input type="password" name="password">
18         <br />
19         <input type="submit" value="注册" />
20         </form>
21     </body>
22 </html>