JavaWeb 实现简单登录、注册功能

1.首先创建一个简单的动态Javaweb项目

2.然后手动建立文件目录：

项目创建好之后，在src下建几个包：

controller：控制器，负责转发请求，对请求进行处理，主要存放servlet；

dao：数据库管理，主要是写数据库操作方法；

model：存放实体类；

service：业务逻辑的处理；

util：存放工具类，在这里我主要是把数据库加载驱动和创立连接、关闭连接封装成了一个静态类。

ps:别忘了在lib文件夹里放入这个jar包，用以连接数据库。

3.下面直接贴上对应的代码：

src代码：

 package com.maike.controller;

 import java.io.IOException;
 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 com.maike.service.UserService;
 import com.maike.service.UserServiceImpl;

 /**
  * Servlet implementation class RegisterServlet
  */
 @WebServlet("/RegisterServlet")
 public class RegisterServlet extends HttpServlet {
     UserService userService = new UserServiceImpl();
     private static final long serialVersionUID = 1L;

     /**
      * @see HttpServlet#HttpServlet()
      */
     public RegisterServlet() {
         super();
         // TODO Auto-generated constructor stub
     }

     /**
      * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
      */
     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
         // TODO Auto-generated method stub
         response.getWriter().append("Served at: ").append(request.getContextPath());
     }

     /**
      * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
      */
     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
         // TODO Auto-generated method stub
         request.setCharacterEncoding("utf-8");
         String userName = request.getParameter("userName");
         String userPwd = request.getParameter("userPwd");
         String userRePwd = request.getParameter("userRePwd");

         int k = userService.insertUser(userName,userPwd,userRePwd);

         if(k > 0) {
             request.getRequestDispatcher("login.jsp").forward(request, response);
         }else {
             request.getRequestDispatcher("register.jsp").forward(request, response);
         }
     }

 }

RegisterServlet

 package com.maike.controller;

 import java.io.IOException;
 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 com.maike.service.UserService;
 import com.maike.service.UserServiceImpl;

 /**
  * Servlet implementation class LoginServlet
  */
 @WebServlet("/LoginServlet")
 public class LoginServlet extends HttpServlet {
     UserService userService = new UserServiceImpl();
     private static final long serialVersionUID = 1L;

     /**
      * @see HttpServlet#HttpServlet()
      */
     public LoginServlet() {
         super();
         // TODO Auto-generated constructor stub
     }

     /**
      * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
      */
     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
         // TODO Auto-generated method stub
         response.getWriter().append("Served at: ").append(request.getContextPath());
     }

     /**
      * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
      */
     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
         // TODO Auto-generated method stub
         request.setCharacterEncoding("utf-8");
         String userName = request.getParameter("userName");
         String uesrPwd = request.getParameter("userPwd");

         int k = userService.judgeLogin(userName,uesrPwd);
         if(k > 0) {
             request.getRequestDispatcher("success.jsp").forward(request, response);
         }else {
             request.getRequestDispatcher("login.jsp").forward(request, response);
         }
     }

 }

LoginServlet

 package com.maike.dao;

 import com.maike.model.User;

 public interface UserDao {

     int insert(String userName,String userPwd);
     User selectByName(String userName);

 }

UserDao

 package com.maike.dao;

 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;

 import com.maike.model.User;
 import com.maike.util.ConnectionUtil;

 public class UserDaoImpl implements UserDao {
     Connection con = null;
     PreparedStatement pt = null;
     ResultSet rs = null;
     String sql;

     @Override
     public int insert(String userName, String userPwd) {
         // TODO Auto-generated method stub
         int k = 0;
         sql = "insert into user value(null,?,?)";
         try {
             con = ConnectionUtil.getConnection();
             pt = con.prepareStatement(sql);
             pt.setString(1, userName);
             pt.setString(2, userPwd);
             k = pt.executeUpdate();
         } catch (SQLException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }finally {
             ConnectionUtil.closeRe(con, pt);
         }
         return k;
     }

     @Override
     public User selectByName(String userName) {
         // TODO Auto-generated method stub
         sql = "select * from user where user_name = ?";
         User user = new User();
         try {
             con = ConnectionUtil.getConnection();
             pt = con.prepareStatement(sql);
             pt.setString(1, userName);
             rs = pt.executeQuery();

             while(rs.next()) {
                 user.setUserId(rs.getInt("user_id"));
                 user.setUserName(rs.getString("user_name"));
                 user.setUserPwd(rs.getString("user_pwd"));
             }
         } catch (SQLException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }finally {
             ConnectionUtil.closeRe(con, pt, rs);
         }
         return user;
     }

 }

UserDaoImpl

 package com.maike.model;

 public class User {

     private int userId;

     private String userName;

     private String userPwd;

     public int getUserId() {
         return userId;
     }

     public void setUserId(int userId) {
         this.userId = userId;
     }

     public String getUserName() {
         return userName;
     }

     public void setUserName(String userName) {
         this.userName = userName;
     }

     public String getUserPwd() {
         return userPwd;
     }

     public void setUserPwd(String userPwd) {
         this.userPwd = userPwd;
     }

     @Override
     public String toString() {
         return "User [userId=" + userId + ", userName=" + userName + ", userPwd=" + userPwd + "]";
     }

 }

User

 package com.maike.service;

 public interface UserService {

     int insertUser(String userName,String userPwd,String userRePwd);
     int judgeLogin(String userName,String userPwd);

 }

UserService

 package com.maike.service;

 import com.maike.dao.UserDao;
 import com.maike.dao.UserDaoImpl;
 import com.maike.model.User;

 public class UserServiceImpl implements UserService {
     UserDao userDao = new UserDaoImpl();

     /**
      * insertUser: 实现注册功能.<br/>
      */
     @Override
     public int insertUser(String userName, String userPwd, String userRePwd) {
         // TODO Auto-generated method stub
         int k = 0;
         if(userName == "" || userName == null || userPwd == "" || userRePwd == null) {
             return k;
         }
         if(!userPwd.equals(userRePwd)) {
             return k;
         }

         k = userDao.insert(userName,userPwd);

         return k;
     }

     /**
      * judgeLogin:登录判断 .<br/>
      */
     @Override
     public int judgeLogin(String userName, String userPwd) {
         // TODO Auto-generated method stub
         int k = 0;
         if(userName == "" || userName == null || userPwd == ""|| userPwd == null) {
             return k;
         }
         User user = userDao.selectByName(userName);

         if(!userPwd.equals(user.getUserPwd())) {
             k = 0;
         }else {
             k = 1;
         }
         return k;
     }

 }

UserServiceImpl

 package com.maike.util;

 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;

 public class ConnectionUtil {
     private static String url = "jdbc:mysql://127.0.0.1/nanfeng?characterEncoding=utf8&useSSL=true";
     private static String rootName = "root";
     private static String rootPwd = "zz201608";

     private ConnectionUtil() {};

     static {
         try {
             /*加载驱动*/
             Class.forName("com.mysql.jdbc.Driver");
         } catch (ClassNotFoundException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }
     }

     /**
      * getConnection:创建连接.<br/>
      * @return
      * @throws SQLException
      */
     public static Connection getConnection() throws SQLException {
         return DriverManager.getConnection(url,rootName,rootPwd);
     }

     /**
      * closeRe:关闭连接.<br/>
      * @param con
      * @param pt
      * @param rs
      */
     public static void closeRe(Connection con,PreparedStatement pt,ResultSet rs) {
         if(rs != null) {
             try {
                 rs.close();
             } catch (SQLException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             }finally {
                 if(pt != null) {
                     try {
                         pt.close();
                     } catch (SQLException e) {
                         // TODO Auto-generated catch block
                         e.printStackTrace();
                     }finally{
                         if(con != null) {
                             try {
                                 con.close();
                             } catch (SQLException e) {
                                 // TODO Auto-generated catch block
                                 e.printStackTrace();
                             }
                         }
                     }
                 }
             }
         }
     }

     /**
      * closeRe:关闭连接.<br/>
      * @param con
      * @param pt
      */
     public static void closeRe(Connection con,PreparedStatement pt) {
         if(pt != null) {
             try {
                 pt.close();
             } catch (SQLException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             }finally {
                 if(con != null) {
                     try {
                         con.close();
                     } catch (SQLException e) {
                         // TODO Auto-generated catch block
                         e.printStackTrace();
                     }
                 }
             }
         }
     }

 }

ConnectionUtil

jsp页面代码：

 <%@ page language="java" contentType="text/html; charset=utf-8"
     pageEncoding="utf-8"%>
 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 <html>
 <head>
 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
 <title>登录页面</title>
 </head>
 <body>
   <br><br><br>
   <h3 align = "center">登录页面</h3>
   <hr>
     <form align = "center" action="LoginServlet" method="post">
         <table align = "center" border="0">
             <tr><td>用户名</td><td><input type="text" name="userName" ></td></tr>
             <tr><td>密码</td><td><input type="password" name="userPwd" ></td></tr>
             <tr><td align = "center"><input type="submit" value = "登录" style="color:blue" ></td><td align = "right"><button><a href = "register.jsp" style="color:blue" >注册</a></button></td></tr>
         </table>

     </form>

 </body>
 </html>

login.jsp

 <%@ page language="java" contentType="text/html; charset=utf-8"
     pageEncoding="utf-8"%>
 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 <html>
 <head>
 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
 <title>注册页面</title>
 </head>
 <body>
   <br><br><br>
   <h3 align = "center">注册页面</h3>
   <hr>
     <form align = "center" action="RegisterServlet" method="post">
         <table align = "center" border="0">
             <tr><td>用户名</td><td><input type="text" name="userName" ></td></tr>
             <tr><td>密码</td><td><input type="password" name="userPwd" ></td></tr>
             <tr><td>确认密码</td><td><input type="password" name="userRePwd" ></td></tr>
             <tr><td align = "center" colspan="2"><input type="submit" value = "注册" style="color:blue" ></td></tr>
         </table>

     </form>
 </body>
 </html>

register.jsp

创建数据库：

 CREATE TABLE nanfeng.`user` (
     user_id INT NOT NULL AUTO_INCREMENT,
     user_name varchar(100) NULL,
     user_pwd varchar(100) NULL,
     CONSTRAINT user_pk PRIMARY KEY (user_id)
 )
 ENGINE=InnoDB
 DEFAULT CHARSET=utf8
 COLLATE=utf8_general_ci;

4.最后，启动服务器，界面效果出来了