jsp&servlet初体验——用户登录功能实现

数据库准备—创建db_login数据库  t_user表

1、创建web工程

2、创建用户model   user.java

 1 package com.gxy.model;
 2
 3 public class User {
 4     private int id;
 5     private String userName;
 6     private String password;
 7
 8     public User() {
 9         super();
10     }
11
12
13     public User(String userName, String password) {
14         super();
15         this.userName = userName;
16         this.password = password;
17     }
18
19
20     public int getId() {
21         return id;
22     }
23     public void setId(int id) {
24         this.id = id;
25     }
26     public String getUserName() {
27         return userName;
28     }
29     public void setUserName(String userName) {
30         this.userName = userName;
31     }
32     public String getPassword() {
33         return password;
34     }
35     public void setPassword(String password) {
36         this.password = password;
37     }
38
39 }

3、创建util包 Dbutil.java

 1 package com.gxy.util;
 2
 3 import java.sql.Connection;
 4 import java.sql.DriverManager;
 5
 6 public class Dbutil {
 7     private String dbUrl ="jdbc:mysql://localhost:3306/db_login";
 8     private String jdbcName="com.mysql.jdbc.Driver";
 9     private String dbUserName="root";
10     private String dbpassword="123456";
11
12     public Connection getcon() throws Exception{
13         Class.forName(jdbcName);
14         Connection con=DriverManager.getConnection(dbUrl,dbUserName,dbpassword);
15         return con;
16     }
17
18     public void closeCon(Connection con) throws Exception{
19         con.close();
20     }
21
22 }

4、创建dao包  UserDao.java

 1 package com.gxy.dao;
 2
 3 import java.sql.Connection;
 4 import java.sql.PreparedStatement;
 5 import java.sql.ResultSet;
 6
 7 import com.gxy.model.User;
 8
 9 public class UserDao {
10     public User login(Connection con,User user) throws Exception{
11         User resultUser=null;
12         String sql="select * from t_user where userName=? and passWord=?";
13         PreparedStatement pst=con.prepareStatement(sql);
14         pst.setString(1, user.getUserName());
15         pst.setString(2,user.getPassword());
16         ResultSet rs=pst.executeQuery();
17         if(rs.next()){
18             resultUser=new User();
19             resultUser.setUserName(rs.getString("userName"));
20             resultUser.setPassword(rs.getString("passWord"));
21         }
22         return resultUser;
23     }
24
25 }

5、创建servlet包  loginServlet

 1 package com.gxy.servlet;
 2
 3 import java.io.IOException;
 4 import java.sql.Connection;
 5
 6 import javax.servlet.RequestDispatcher;
 7 import javax.servlet.ServletException;
 8 import javax.servlet.http.HttpServlet;
 9 import javax.servlet.http.HttpServletRequest;
10 import javax.servlet.http.HttpServletResponse;
11 import javax.servlet.http.HttpSession;
12
13 import com.gxy.dao.UserDao;
14 import com.gxy.model.User;
15 import com.gxy.util.Dbutil;
16
17 public class loginServlet extends HttpServlet{
18
19     /**
20      *
21      */
22     private static final long serialVersionUID = 1L;
23
24     Dbutil dbutil=new Dbutil();
25     UserDao userDao=new UserDao();
26     @Override
27     protected void doGet(HttpServletRequest req, HttpServletResponse resp)
28             throws ServletException, IOException {
29         this.doPost(req, resp);
30     }
31
32     @Override
33     protected void doPost(HttpServletRequest req, HttpServletResponse resp)
34             throws ServletException, IOException {
35         String userName=req.getParameter("userName");
36         String passWord=req.getParameter("passWord");
37
38         Connection con=null;
39         try {
40             User user=new User(userName,passWord);
41             con=dbutil.getcon();
42             User resultUser=userDao.login(con, user);
43             if(resultUser==null){
44                 System.out.println("no");
45             }else{
46                 HttpSession session=req.getSession();
47                 session.setAttribute("userName", resultUser.getUserName());
48                 session.setAttribute("passWord", resultUser.getPassword());
49                 resp.sendRedirect("target.jsp");
50             }
51         } catch (Exception e) {
52             // TODO Auto-generated catch block
53             e.printStackTrace();
54         }
55
56     }
57
58 }

6、用户登录界面  login.jsp

 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 ‘login.jsp‘ starting page</title>
13
14     <meta http-equiv="pragma" content="no-cache">
15     <meta http-equiv="cache-control" content="no-cache">
16     <meta http-equiv="expires" content="0">
17     <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
18     <meta http-equiv="description" content="This is my page">
19     <!--
20     <link rel="stylesheet" type="text/css" href="styles.css">
21     -->
22
23   </head>
24
25   <body>
26   <form action="login" method="post">
27     <table>
28         <tr>
29             <td>用户名：</td>
30             <td><input type="text" id="userName" name="userName"></td>
31         </tr>
32         <tr>
33             <td>密码：</td>
34             <td><input type="password" id="passWord" name="passWord"></td>
35         </tr>
36         <tr>
37             <td colspan="2"><input type="submit" value="提交" ></td>
38         </tr>
39     </table>
40    </form>
41   </body>
42 </html>

跳转界面  target.jsp

 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 ‘target.jsp‘ starting page</title>
13
14     <meta http-equiv="pragma" content="no-cache">
15     <meta http-equiv="cache-control" content="no-cache">
16     <meta http-equiv="expires" content="0">
17     <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
18     <meta http-equiv="description" content="This is my page">
19     <!--
20     <link rel="stylesheet" type="text/css" href="styles.css">
21     -->
22
23   </head>
24
25   <body>
26     <h1>用户名：<%=session.getAttribute("userName") %></h1>
27     <h1>密码：<%=session.getAttribute("passWord") %></h1>
28   </body>
29 </html>

7、运行结果

原文地址：https://www.cnblogs.com/guoxiangyue/p/8439856.html