关于MVC模式的登录注册

最近初学jsp，顺便编写了一个基于MVC开发模式的登录注册

1、util包用于连接数据库操作

 1 package com.util;
 2 
 3 import java.sql.Connection;
 4 import java.sql.DriverManager;
 5 import java.sql.SQLException;
 6 
 7 public class DbUtil {
 8     
 9     private String url="jdbc:mysql://localhost:3306/test";
10     private String user="root";
11     private String password="root";
12     private String driver="com.mysql.jdbc.Driver";
13     
14     public Connection getCon() throws Exception{
15         Class.forName(driver);
16         Connection con=DriverManager.getConnection(url, user, password);
17         return con;
18     }
19     
20     public static void getClose(Connection con) throws SQLException{
21         if(con!=null){
22             con.close();
23         }
24     }
25     
26     /*public static void main(String[] args) {
27         DbUtil db=new DbUtil();
28         try {
29             db.getCon();
30             System.out.println("测试连接数据库，连接成功");
31         } catch (Exception e) {
32             // TODO Auto-generated catch block
33             e.printStackTrace();
34             System.out.println("测试连接数据库，连接失败");
35         }
36         
37     }*/
38 }

View Code

2、model层对于成员变量的get set方法控制

 1 package com.model;
 2 
 3 import java.sql.DriverManager;
 4 
 5 import com.mysql.jdbc.Connection;
 6 import com.mysql.jdbc.PreparedStatement;
 7 
 8 public class User {
 9 
10     private int id;
11     private String username;
12     private String password;
13     
14     
15     public User() {
16         super();
17     }
18     public User(String username, String password) {
19         super();
20         this.username = username;
21         this.password = password;
22     }
23     public int getId() {
24         return id;
25     }
26     public void setId(int id) {
27         this.id = id;
28     }
29     public String getUsername() {
30         return username;
31     }
32     public void setUsername(String username) {
33         this.username = username;
34     }
35     public String getPassword() {
36         return password;
37     }
38     public void setPassword(String password) {
39         this.password = password;
40     }
41     
42 
43 }

View Code

3.dao层用于操作数据库的增删改查方法

  1 package com.dao;
  2 
  3 import java.sql.Connection;
  4 import java.sql.PreparedStatement;
  5 import java.sql.ResultSet;
  6 import java.sql.SQLException;
  7 
  8 
  9 import com.ningmeng.model.User;
 10 
 11 public class UserDao {
 12     
 13     public User login(Connection con,User user) throws SQLException{
 14         User resultUser=null;
 15         String sql="select * from user where name=? and password=?";
 16         PreparedStatement ps=con.prepareStatement(sql);//
 17         ps.setString(1, user.getUsername());
 18         ps.setString(2, user.getPassword());
 19         ResultSet rs=ps.executeQuery();
 20         if(rs.next()){
 21             resultUser=new User();
 22             resultUser.setUsername(rs.getString("name"));
 23             resultUser.setPassword(rs.getString("password"));
 24         }
 25         return resultUser;
 26     }
 27     public boolean insert(Connection con,User user)
 28     {
 29         String sql = "INSERT INTO user(name,password) VALUES (?,?)";  //添加的SQL语句
 30          boolean flag=false;  
 31          try{  
 32              PreparedStatement psta=con.prepareStatement(sql);// 
 33              psta.setString(1, user.getUsername());  
 34              psta.setString(2, user.getPassword());  
 35              flag=psta.executeUpdate()>0;
 36          }catch(Exception e){  
 37              e.printStackTrace();  
 38          }
 39              try {
 40                 con.close();
 41             } catch (SQLException e) {
 42                 
 43                 e.printStackTrace();
 44             }
 45              return flag;      
 46     }
 47     
 48     //通过id查找  
 49     public User selectById(Connection con,int id){  
 50          
 51         PreparedStatement psta=null;  
 52         ResultSet rs=null;  
 53         User user=null;  
 54         String sql="select * from user where id=?";  
 55         try{  
 56             psta=con.prepareStatement(sql);  
 57             psta.setInt(1, id);  
 58             rs=psta.executeQuery();  
 59             if(rs.next()){  
 60                 user=new User();  
 61                 user.setId(rs.getInt(1));  
 62                 user.setUsername(rs.getString(2));  
 63                 user.setPassword(rs.getString(3));  
 64 
 65             }  
 66         }catch(Exception e){  
 67             e.printStackTrace();  
 68         } 
 69             try{  
 70                 con.close();  
 71             }catch(Exception e){  
 72                 e.printStackTrace();  
 73             }  
 74             return user;    
 75     }
 76   //更新方法（修改数据）（改）  
 77     public boolean update(Connection con,User user){  
 78         PreparedStatement psta=null;  
 79         String sql="update user set name=?,password=? where id=?";  
 80         boolean flag=false;  
 81         try{  
 82             psta=con.prepareStatement(sql);  
 83             psta.setString(1, user.getUsername());  
 84             psta.setString(2, user.getPassword());   
 85             psta.setInt(3,user.getId());  
 86             flag=psta.executeUpdate()>0;  
 87         }catch(Exception e){  
 88             e.printStackTrace();  
 89         }
 90             try{  
 91                 con.close();  
 92             }catch(Exception e){  
 93                 e.printStackTrace();  
 94             }  
 95             return flag;  
 96     } 
 97     
 98     public boolean deleteAdmin(Connection con,int id){  //删除
 99         String sql = "delete from user where id = ?";  //删除的SQL语句，根据ID删除
100         try {
101             PreparedStatement pst = con.prepareStatement(sql);
102             pst.setInt(1, id);
103             int count = pst.executeUpdate();
104             pst.close();
105             return count>0?true:false;  //是否删除的判断
106         } catch (SQLException e) {
107             e.printStackTrace();
108         }
109         return false;
110     }
111     
112 }

View Code

4、Servlet控制连接前台界面

 1 package com.web;
 2 
 3 import java.io.IOException;
 4 import java.sql.Connection;
 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 import com.ningmeng.dao.UserDao;
13 import com.ningmeng.model.User;
14 import com.ningmeng.util.DbUtil;
15 
16 public class LoginServlet extends HttpServlet{
17 
18     DbUtil db=new DbUtil();
19     UserDao userDao=new UserDao();
20     /**
21      * 
22      */
23     private static final long serialVersionUID = 1L;
24 
25     @Override
26     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
27         this.doPost(request, response);
28     }
29 
30     @Override
31     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
32         String username=request.getParameter("username");
33         String password=request.getParameter("password");
34         Connection con=null;
35         try {
36             User user=new User(username,password);
37             con=db.getCon();
38             User currentUser=userDao.login(con, user);
39             if(currentUser==null){
40                 //System.out.println("no");
41                 request.setAttribute("error", "用户名或者密码错误");
42                 request.setAttribute("username", username);
43                 request.setAttribute("password", password);
44                 request.getRequestDispatcher("login.jsp").forward(request, response);
45             }else{
46                 //System.out.println("yes");
47                 HttpSession session=request.getSession();
48                 session.setAttribute("currentUser",currentUser);
49                 response.sendRedirect("main.jsp");
50             }
51         } catch (Exception e) {
52             // TODO Auto-generated catch block
53             e.printStackTrace();
54         }
55         
56     }
57     
58     
59 }

LoginServlet

 1 package com.web;
 2 
 3 import java.io.IOException;
 4 import java.sql.Connection;
 5 
 6 import javax.servlet.ServletException;
 7 import javax.servlet.annotation.WebServlet;
 8 import javax.servlet.http.HttpServlet;
 9 import javax.servlet.http.HttpServletRequest;
10 import javax.servlet.http.HttpServletResponse;
11 
12 import com.ningmeng.dao.UserDao;
13 import com.ningmeng.model.User;
14 import com.ningmeng.util.DbUtil;
15 
16 /**
17  * Servlet implementation class RegistServlet
18  */
19 @WebServlet("/RegistServlet")
20 public class RegistServlet extends HttpServlet {
21     private static final long serialVersionUID = 1L;
22        
23     DbUtil db=new DbUtil();
24     UserDao userDao=new UserDao();
25     /**
26      * @see HttpServlet#HttpServlet()
27      */
28     public RegistServlet() {
29         super();
30         // TODO Auto-generated constructor stub
31     }
32 
33     /**
34      * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
35      */
36     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
37         String username=request.getParameter("username");
38         String password=request.getParameter("password");
39         Connection con=null;
40         
41         User user=new User(username,password);
42         try {
43             con=db.getCon();
44         } catch (Exception e) {
45             
46             e.printStackTrace();
47         }
48         boolean current=userDao.insert(con, user);
49         System.out.print(current);
50         System.out.print(user.getUsername());
51         if(current){
52              request.setAttribute("error", "注册成功");
53             
54         }else{
55              request.setAttribute("error", "注册失败");
56              request.getRequestDispatcher("Regist.jsp").forward(request, response);
57         }
58         
59     }
60 
61     /**
62      * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
63      */
64     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
65         // TODO Auto-generated method stub
66         doGet(request, response);
67     }
68 
69 }

RegistServlet

5、修改web.xml对应的servlet

6、前台页面展示

 1 <%@ page language="java" contentType="text/html; charset=gbk"
 2     pageEncoding="gbk"%>
 3 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 4 <html>
 5 <head>
 6 <meta http-equiv="Content-Type" content="text/html; charset=gbk">
 7 <title>Insert title here</title>
 8 </head>
 9 <body>
10 <form action="login" method="post">
11      <table>
12          <tr>
13              <th colspan="2">登录界面</th>
14          </tr>
15          <tr>
16              <td>账号</td>
17              <td><input type="text" id="username" name="username" value="${username}"></td>
18          </tr>
19          <tr>
20              <td>密码：</td>
21              <td><input type="text" id="password" name="password" value="${password}"></td>
22          </tr>
23          <tr>
24              <td><input type="submit" value="提交"></td>
25              <td><font color="red">${error}</font></td>
26          </tr>
27      </table>
28  </form>
29  </body>
30 </html>

 1 <%@ page language="java" contentType="text/html; charset=gbk"
 2     pageEncoding="gbk"%>
 3 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 4 <html>
 5 <head>
 6 <meta http-equiv="Content-Type" content="text/html; charset=gbk">
 7 <title>Insert title here</title>
 8 </head>
 9 <body>
10 <form action="login" method="post">
11      <table>
12          <tr>
13              <th colspan="2">注册界面</th>
14          </tr>
15          <tr>
16              <td>账号</td>
17              <td><input type="text" id="username" name="username" ></td>
18          </tr>
19          <tr>
20              <td>密码：</td>
21              <td><input type="text" id="password" name="password" ></td>
22          </tr>
23          <tr>
24              <td><input type="submit" value="提交"></td>
25              <td><font color="red">${error}</font></td>
26          </tr>
27      </table>
28  </form>
29  </body>
30 </html>

regist

 1 <%@ page language="java" contentType="text/html; charset=gbk"
 2     pageEncoding="gbk"%>
 3 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 4 <html>
 5 <head>
 6 <meta http-equiv="Content-Type" content="text/html; charset=gbk">
 7 <title>Insert title here</title>
 8 </head>
 9 <body>
10  <p>登录成功</p>
11  当前用户：${currentUser.username}<br/>
12  当前密码：${currentUser.password}<br/>
13  </body>
14 </html>

main