利用session完成用户登陆

时间：2021-04-29 07:08:55
 package cn.itcast.cookie;

 import java.io.IOException;

 import java.io.PrintWriter;

 import java.util.List;

 import javax.servlet.ServletException;

 import javax.servlet.http.Cookie;

 import javax.servlet.http.HttpServlet;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 import javax.servlet.http.HttpSession;

 import cn.itcast.Db;

 import cn.itcast.Db1;

 import cn.itcast.User;

 public class SessionDemo extends HttpServlet {

     public void doGet(HttpServletRequest request, HttpServletResponse response)

             throws ServletException, IOException {

         response.setCharacterEncoding("UTF-8");

         response.setContentType("text/html;charset=UTF-8");

         PrintWriter out = response.getWriter();

         String username = request.getParameter("username");

         String password = request.getParameter("password");

         List<User> list = Db1.getAll();

         for (User user : list) {

             if(user.getUsername().equals(username)&&user.getPassword().equals(password)){

                 request.getSession().setAttribute("user", user);//登录成功，向session存入一个登录标记

                 response.sendRedirect("/ServletDemo/index.jsp");

                 return;

             }

         }

         out.write("用户名或密码错误！");

     }

     public void doPost(HttpServletRequest request, HttpServletResponse response)

             throws ServletException, IOException {

     }

 }
 package cn.itcast.cookie;

 import java.io.IOException;

 import java.io.PrintWriter;

 import javax.servlet.ServletException;

 import javax.servlet.http.HttpServlet;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 import javax.servlet.http.HttpSession;

 //完成任务注销

 public class SessionDemo2 extends HttpServlet {

     public void doGet(HttpServletRequest request, HttpServletResponse response)

             throws ServletException, IOException {

         response.setCharacterEncoding("UTF-8");

         response.setContentType("text/html;charset=UTF-8");

         PrintWriter out = response.getWriter();

         HttpSession session = request.getSession();

         if(session==null){

             response.sendRedirect("/ServletDemo/index.jsp");

             return;

         }

         session.removeAttribute("user");

         response.sendRedirect("/ServletDemo/index.jsp");

     }

     public void doPost(HttpServletRequest request, HttpServletResponse response)

             throws ServletException, IOException {

     }

 }
 package cn.itcast;

 import java.util.ArrayList;

 import java.util.List;

 public class Db1 {

     public static List list = new ArrayList();

     static{

         list.add(new User("aaa","123"));

         list.add(new User("bbb","123"));

         list.add(new User("ccc","123"));

         list.add(new User("ddd","123"));

     }

     public static List getAll(){

         return list;

     }

 }
 package cn.itcast;

 public class User {

     private String username;

     public User() {

         super();

     }

     public User(String username, String password) {

         super();

         this.username = username;

         this.password = password;

     }

     private String password;

     public String getUsername() {

         return username;

     }

     public void setUsername(String username) {

         this.username = username;

     }

     public String getPassword() {

         return password;

     }

     public void setPassword(String password) {

         this.password = password;

     }

 }
 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

 <%

 String path = request.getContextPath();

 String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";

 %>

 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

 <html>

   <head>

     <base href="<%=basePath%>">

     <title>My JSP 'index.jsp' starting page</title>

     <meta http-equiv="pragma" content="no-cache">

     <meta http-equiv="cache-control" content="no-cache">

     <meta http-equiv="expires" content="0">

     <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">

     <meta http-equiv="description" content="This is my page">

     <!--

     <link rel="stylesheet" type="text/css" href="styles.css">

     -->

   </head>

   <body>

     欢迎您：${user.username }<a href="/ServletDemo/register.html">登录</a> <a href="/ServletDemo/servlet/SessionDemo2">退出登录</a>

   </body>

 </html>
 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

 <html>

     <head>

         <title>register.html</title>

     </head>

     <style>

     </style>

     <body>

         <form action="/ServletDemo/servlet/SessionDemo" method="get">

         用户名：

         <input type="text" name="username">

         <br />

         密码：

         <input type="password" name="password">

         <br />

         <input type="submit" value="注册" />

         </form>

     </body>

 </html>

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