项目案例模板之登录注册的实现

Posted 2022-10-13 zyx110

项目案例模板之登录注册的实现

案例演示

 

 

 

 

 

 

  

案例代码

设计表

 

 

 

pom.xml

 <dependencies>
   <dependency>
     <groupId>junit</groupId>
     <artifactId>junit</artifactId>
     <version>4.11</version>
     <scope>test</scope>
   </dependency>
   <dependency>
     <groupId>mysql</groupId>
     <artifactId>mysql-connector-java</artifactId>
     <version>5.0.5</version>
   </dependency>
   <dependency>
     <groupId>javax.servlet</groupId>
     <artifactId>javax.servlet-api</artifactId>
     <version>3.1.0</version>
     <scope>provided</scope>
   </dependency>
   <dependency>
     <groupId>org.junit.jupiter</groupId>
     <artifactId>junit-jupiter-api</artifactId>
     <version>RELEASE</version>
     <scope>compile</scope>
   </dependency>
 </dependencies>

 

jdbc

JDBCUtils.java

 package jdbc;
 ?
 import org.junit.jupiter.api.Test;
 ?
 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.SQLException;
 ?
 public class JDBCUtils 
     public static Connection connection;
     private static String url="jdbc:mysql://localhost:3306/aaa?useUnicode=true&characterEncoding=utf-8";
     private static String username="root";
     private static String password="root";
 ?
     static
         try 
             Class.forName("com.mysql.jdbc.Driver");
             connection = DriverManager.getConnection(url,username,password);
 ?
          catch (ClassNotFoundException e) 
             e.printStackTrace();
          catch (SQLException e) 
             e.printStackTrace();
         
     
 ?
     public static Connection getConnection()
         return connection;
     
 ?
     @Test
     public void test()
         Connection connection = JDBCUtils.getConnection();
         System.out.println(connection);
     
 

entity

User.java

 package entity;
 ?
 public class User 
     private int id;
     private String username;
     private String password;
 ?
     public User() 
     
 ?
     public User(int id, String username, String password) 
         this.id = id;
         this.username = username;
         this.password = password;
     
 ?
     @Override
     public String toString() 
         return "User" +
                 "id=" + id +
                 ", username=‘" + username + ‘\\‘‘ +
                 ", password=‘" + password + ‘\\‘‘ +
                 ‘‘;
     
 ?
     public int getId() 
         return id;
     
 ?
     public void setId(int id) 
         this.id = id;
     
 ?
     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;
     
 

dao

UserDao.java

 package dao;
 ?
 import entity.User;
 import jdbc.JDBCUtils;
 ?
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.List;
 ?
 public class UserDao 
     private Connection connection = JDBCUtils.getConnection();
     private PreparedStatement ps;
 ?
     /*
     *添加用户
     * */
     public int add(User user) throws Exception
         String sql = "insert into user(username,password) values(?,?)";
 ?
             ps=connection.prepareStatement(sql);
             ps.setObject(1,user.getUsername());
             ps.setObject(2,user.getPassword());
             int exe = ps.executeUpdate();
             return exe;
     
     public int delete(int id) throws SQLException 
         String sql = "delete from user where id=?";
         ps = connection.prepareStatement(sql);
 ?
         /*
          * 删除用户
          * */
         ps.setObject(1,id);
         int exe = ps.executeUpdate();
         return exe;
     
 ?
     /*
     * 修改用户
     * */
     public int update(User user) throws SQLException 
         String sql = "update user set username=? , password=? where id=?";
         ps = connection.prepareStatement(sql);
         ps.setObject(1,user.getUsername());
         ps.setObject(2,user.getPassword());
         ps.setObject(3,user.getId());
          return ps.executeUpdate();
 ?
     
 ?
     /*
     * 查询所有用户
     * */
     public List<User> findAll() throws SQLException 
         String sql = "select * from user";
         ps=connection.prepareStatement(sql);
         ResultSet rs =ps.executeQuery();
         List<User> list = new ArrayList<User>();
         while(rs.next())
             //以 Java 编程语言中 int 的形式获取此 ResultSet 对象的当前行中指定列的值。
             int id = rs.getInt("id");
             String username = rs.getString("username");
             String password = rs.getString("password");
             User u = new User(id,username,password);
             list.add(u);
 ?
         
         return list;
     
 ?
 /*
 * 通过id查询用户
 * */
     public User findById(int id) throws SQLException 
         String sql = "select * from user where id=?";
         ps=connection.prepareStatement(sql);
         ps.setInt(1,id);
         ResultSet rs = ps.executeQuery();
 ?
         User u = null;
         while (rs.next())
             int uid = rs.getInt("id");
             String username = rs.getString("username");
             String password = rs.getString("password");
 ?
 ?
             u = new User(uid,username,password);
         
 ?
         return u;
     
 ?
 ?
     /*
     * 用户登录
     * */
     public User login(User user) throws SQLException 
         String sql = "select * from user where username=? and password=?";
         ps = connection.prepareStatement(sql);
         ps.setObject(1,user.getUsername());
         ps.setObject(2,user.getPassword());
 ?
         ResultSet rs = ps.executeQuery();
         User u = null;
 ?
         while (rs.next())
             int uid = rs.getInt("id");
             String username = rs.getString("username");
             String password = rs.getString("password");
             u = new User(uid,username,password);
         
 ?
         return u;
     
 

service

UserService.java

 package service;
 ?
 import dao.UserDao;
 import entity.User;
 ?
 import java.sql.SQLException;
 import java.util.List;
 ?
 public class UserService 
     private UserDao userDao = new UserDao();
 ?
     public int add(User user) throws Exception 
         return userDao.add(user);
     
 ?
     public int delete(int id) throws SQLException 
         return userDao.delete(id);
     
 ?
     public int update(User user) throws SQLException 
         return userDao.update(user);
     
 ?
     public List<User> findAll() throws SQLException 
         return userDao.findAll();
 ?
     
 ?
     public User findByID(int id) throws SQLException 
         return userDao.findById(id);
     
 ?
     public User login(User user) throws SQLException 
         return userDao.login(user);
     
 

servlet

LoginServlet.java

 package servlet;
 ?
 import entity.User;
 import service.UserService;
 ?
 import javax.servlet.ServletException;
 import javax.servlet.annotation.WebServlet;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import java.io.IOException;
 import java.sql.SQLException;
 ?
 @WebServlet("/login")
 public class LoginServlet extends HttpServlet 
 ?
     @Override
     protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException 
         doPost(req, resp);
     
 ?
     @Override
     protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException 
         req.setCharacterEncoding("utf-8");
         resp.setCharacterEncoding("utf-8");
 ?
         //接受请求参数
         String username = req.getParameter("username");
         String password = req.getParameter("password");
 ?
         User user = new User();
         user.setUsername(username);
         user.setPassword(password);
 ?
         //查询数据
         UserService us = new UserService();
         User u = null;
 ?
         try 
             u=us.login(user);
             //跳转
             if (u==null)
                 req.setAttribute("mess","账号或密码错误");
                 req.getRequestDispatcher("login.jsp").forward(req,resp);
             else 
                 req.getSession().setAttribute("user",u);
                 resp.sendRedirect("main.jsp");
             
          catch (SQLException e) 
             e.printStackTrace();
         
 ?
 ?
 ?
 ?
     
 

 

RegServlet.java

 package servlet;
 ?
 import dao.UserDao;
 import entity.User;
 ?
 import javax.servlet.ServletException;
 import javax.servlet.annotation.WebServlet;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import java.io.IOException;
 @WebServlet("/reg")
 public class RegServlet extends HttpServlet 
     @Override
     protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException 
         doPost(req, resp);
     
 ?
     @Override
     protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException 
         req.setCharacterEncoding("utf-8");
         resp.setCharacterEncoding("utf-8");
 ?
         //接受请求参数
         String username = req.getParameter("username");
         String password = req.getParameter("password");
 ?
         User u = new User();
         u.setUsername(username);
         u.setPassword(password);
 ?
         UserDao dao = new UserDao();
         int i = 0;
 ?
         try 
             i=dao.add(u);
          catch (Exception e) 
             e.printStackTrace();
         
 ?
 ?
         //跳转
         if(i>0)
             req.setAttribute("mess","注册成功");
             resp.sendRedirect("login.jsp");
         else
             req.setAttribute("mess","注册失败");
             req.getRequestDispatcher("regist.jsp").forward(req,resp);
         
 ?
 ?
     
 

 

jsp

web.xml

 <!DOCTYPE web-app PUBLIC
  "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
  "http://java.sun.com/dtd/web-app_2_3.dtd" >
 ?
 <web-app>
   <display-name>Archetype Created Web Application</display-name>
 ?
   <welcome-file-list>
     <welcome-file>regist.jsp</welcome-file>
   </welcome-file-list>
 </web-app>

regist.jsp

 <%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
 <html>
 <head>
     <title>注册</title>
 </head>
 <body>
 <h1>用户注册</h1>
 <hr>
 <form action="reg" method="post">
     <p>
         用户名：<input type="text" name="username">
     </p>
     <p>
         密码：<input type="text" name="password">
     </p>
     <p>
         <input type="submit" value="注册">
     </p>
 ?
 </form>
 ?
 $mess
 ?
 </body>
 </html>

 

login.jsp

 <%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
 <html>
 <head>
     <title>登录</title>
 </head>
 <body>
 <h1>用户登录</h1>
 <hr>
 <form action="login" method="post">
     <p>
         用户名：<input type="text" name="username">
     </p>
     <p>
         密码：<input type="text" name="password">
     </p>
     <p>
         <input type="submit" value="登录">
     </p>
 ?
 </form>
 ?
 $mess
 ?
 </body>
 </html>

 

main.jsp

 <%--
   Created by IntelliJ IDEA.
   User: Lenovo
   Date: 2019/4/25
   Time: 9:11
   To change this template use File | Settings | File Templates.
 --%>
 ?
 <%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
 <html>
 <head>
     <title>主页</title>
 </head>
 <body>
 <h1>欢迎使用本系统</h1>
 当前用户：$sessionScope.user.username
 </body>
 </html>

 

 

 

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