✅作者简介：大家好，我是Leo，热爱Java后端开发者，一个想要与大家共同进步的男人😉😉
🍎个人主页：Leo的博客
💞当前专栏： Java从入门到精通
✨特色专栏： MySQL学习
🥭本文内容：使用JSP+Servlet+MySQL实现登录注册功能
🖥️个人小站 ：个人博客，欢迎大家访问
📚个人知识库： Leo知识库，欢迎大家访问
1.前言
大家好，我是Leo哥🫣🫣🫣，前几天一个在大学的粉丝跟我说：Leo哥，我们最近要搞那个Java期末作业，要求是通过Javaweb知识点，使用JDBC，MySQL，JSP,Servlet等技术实现一个登录和注册功能，能不能出一期教程啊，老师啥也不教。听到这里我也是感触颇深，让我看到我之前的影子，当时老师也是啥都不教，就念个PPT，啥都要咱们自己琢磨。既然这样，咱们就出一期保姆级教程。后面也会出一些demo案例放到这个系列，第一期就先来点简单的开胃菜吧好了，话不多说让我们开始吧😎😎😎。
2.环境配置
首先Leo哥这里先声明一下本次教程的环境配置哈，大家可以跟我横向对比。
因为是比较基础的一篇，考虑到做期末作业，没有接触到Maven，所以我们这里就还是使用原生jar包的方式哈。
环境:
- Intellij IDEA 2023
- MySQL8.0
- Tomcat 8.5
- JDK8
- JDBC
- Navicat 16
3.项目创建
首先我会带大家从零创建一个JavaWeb项目，然后进行环境测试没问题之后，我们再继续往下进行。
打开IDEA，File — New — Project进行创建
开始创建项目，这里我们直接进模块创建。
查看我们的项目结构，并引入MySQL依赖
添加Tomcat依赖
配置Tomcat服务器
首先点击IDEA，最上面，点击Edit Configuration进行配置
然后依次按照我图中点击即可。
然后依次点击选择自己的Artifacts进行配置。
首先第一步检查配置一下自己本地的Tomcat路径，没问题之后，然后选择我们项目的访问路径，最后点击apply。
最后我们启动项目，如果能访问到默认的JSP页面，说明我们项目环境搭建成功了。
欧克，我们环境搭建篇大功告成!!!
4.数据库准备
4.1 SQL建表语句
大家可通过自行创建SQL表
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`username` varchar(50) NOT NULL DEFAULT 'default',
`password` varchar(50) NOT NULL DEFAULT '123456',
`phone` varchar(50) NOT NULL ,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=latin1;
4.2 插入数据
INSERT INTO `user` VALUES (1, 'jack', '19978786751', '123456');
INSERT INTO `user` VALUES (2, 'tony', '19975067512', '123123');
INSERT INTO `user` VALUES (3, 'lisa', '19971286751', '123123');
5.编写后端代码
5.1 代码及项目结构总览
5.2 编写实体类
package org.javatop.case01.domain;
/**
* @author : Leo
* @version 1.0
* @date 2023-11-28 20:57
* @description :
*/
public class User {
private int id;
private String username;
private String password;
private String phone;
public User(int id, String username, String password, String phone) {
this.id = id;
this.username = username;
this.password = password;
this.phone = phone;
}
public String getPhone() {
return phone;
}
public void setPhone(String phone) {
this.phone = phone;
}
public User() {
}
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;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", username='" + username + '\'' +
", password='" + password + '\'' +
", phone='" + phone + '\'' +
'}';
}
}
5.3 编写Dao接口
package org.javatop.case01.dao;
import org.javatop.case01.domain.User;
/**
* @author : Leo
* @version 1.0
* @date 2023-11-28 20:59
* @description :
*/
public interface UserDao {
// 登录
User login(String username, String password);
// 注册
Boolean register(User user);
}
5.4 编写Dao实现类
package org.javatop.case01.dao.impl;
import org.javatop.case01.dao.UserDao;
import org.javatop.case01.domain.User;
import org.javatop.case01.utils.JdbcUtil;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
/**
* @author : Leo
* @version 1.0
* @date 2023-11-28 21:01
* @description :
*/
public class UserDaoImpl implements UserDao {
@Override
public User login(String username, String password) {
User user = null;
Connection connection = null;
PreparedStatement preparedStatement = null;
ResultSet resultSet = null;
try {
connection = JdbcUtil.getConnection();
String sql = "select * from user where username = ? and password= ?";
preparedStatement = connection.prepareStatement(sql);
preparedStatement.setString(1, username);
preparedStatement.setString(2, password);
resultSet = preparedStatement.executeQuery();
if(resultSet.next()){
user = new User();
user.setId(resultSet.getInt("id"));
user.setUsername(resultSet.getString("username"));
user.setPassword(resultSet.getString("password"));
user.setPhone(resultSet.getString("phone"));
System.out.println("登录成功" + user.toString());
} else {
System.out.println("用户名或者密码错误");
}
} catch (Exception e) {
e.printStackTrace();
} finally {
JdbcUtil.release(resultSet, preparedStatement, connection);
}
return user;
}
@Override
public Boolean register(User user) {
Connection connection = null;
PreparedStatement preparedStatement = null;
ResultSet resultSet = null;
int result = 0;
try {
connection = JdbcUtil.getConnection();
String sql = "insert into user(username, password) values (?, ?);";
preparedStatement = connection.prepareStatement(sql);
preparedStatement.setString(1, user.getUsername());
preparedStatement.setString(2, user.getPassword());
result = preparedStatement.executeUpdate();
} catch (Exception e) {
e.printStackTrace();
} finally {
JdbcUtil.release(resultSet, preparedStatement, connection);
}
// 三目表达式，result等1则人会true，否则返回false
return result == 1 ? true:false;
}
}
5.5 实现Servlet
1.LoginServlet
package org.javatop.case01.controller;
import org.javatop.case01.dao.UserDao;
import org.javatop.case01.dao.impl.UserDaoImpl;
import org.javatop.case01.domain.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;
/**
* @author : Leo
* @version 1.0
* @date 2023-12-02 14:34
* @description :
*/
@WebServlet(name = "/login")
public class LoginServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request,response);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
// 获取前端页面传过来的值
String username = request.getParameter("username");
String password = request.getParameter("password");
// 执行查询数据库逻辑
UserDao userDao = new UserDaoImpl();
User user = userDao.login(username, password);
// 如果根据用户名和密码能查得到值
if (user != null) {
request.setAttribute("user", user);
request.getRequestDispatcher("/success.jsp").forward(request, response);
} else { // 用户名或者密码错误执行以下代码
request.setAttribute("message", "用户名或者密码错误");
request.getRequestDispatcher("/defeat.jsp").forward(request, response);
}
}
}
2.RegisterServlet
package org.javatop.case01.controller;
import org.javatop.case01.dao.UserDao;
import org.javatop.case01.dao.impl.UserDaoImpl;
import org.javatop.case01.domain.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;
/**
* @author : Leo
* @version 1.0
* @date 2023-12-02 16:28
* @description : 注册接口
*/
@WebServlet(name = "/register")
public class RegisterServlet extends HttpServlet {
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doPut(req, resp);
}
@Override
protected void doPut(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
req.setCharacterEncoding("UTF-8");
resp.setContentType("text/html;charset=UTF-8");
String username = req.getParameter("username");
String password = req.getParameter("password");
User user = new User();
user.setUsername(username);
user.setPassword(password);
UserDao userDao = new UserDaoImpl();
if (userDao.register(user)) {
System.out.println("注册成功");
// 注册成功，跳转登录页面
req.getRequestDispatcher("register-success.jsp").forward(req,resp);
} else {
System.out.println("注册失败");
req.setAttribute("message", "注册失败");
req.getRequestDispatcher("register.jsp").forward(req,resp);
}
}
}
5.6 编写数据库连接工具类
package org.javatop.case01.utils;
import java.sql.*;
/**
* @author : Leo
* @version 1.0
* @date 2023-11-28 20:59
* @description : 数据库连接工具类
*/
public class JdbcUtil {
/**
* 1、获取Connection
* @return Connection
* @throws Exception
*/
public static Connection getConnection() throws Exception {
Class.forName("com.mysql.cj.jdbc.Driver");
return DriverManager.getConnection("jdbc:mysql://localhost:3306/test","root", "root");
}
/**
* 2、释放资源
* @param resultSet resultSet
* @param statement statement
* @param connection connection
*/
public static void release(ResultSet resultSet, Statement statement, Connection connection) {
if (resultSet != null) {
try {
resultSet.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (statement != null) {
try {
statement.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (connection != null) {
try {
connection.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
6.编写前端代码
这里为了演示效果我实现了两个简单的登录注册页面
6.1 登录页面
<%--
Created by IntelliJ IDEA.
User: Administrator
Date: 2023/11/28
Time: 20:52
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html>
<head>
<title>Login Page</title>
<link rel="stylesheet" type="text/css" href="style.css">
</head>
<body>
<div class="form-container">
<h2>登录</h2>
<form action="/login" method="post">
<input type="text" placeholder="Username" name="username" required>
<input type="password" placeholder="Password" name="password" required>
<button type="submit">Login</button>
<a href="register.jsp">去注册</a>
</form>
</div>
</body>
</html>
6.2 注册页面
<%--
Created by IntelliJ IDEA.
User: Administrator
Date: 2023/11/28
Time: 20:52
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html>
<head>
<title>Login Page</title>
<link rel="stylesheet" type="text/css" href="style.css">
</head>
<body>
<div class="form-container">
<h2>注册</h2>
<form action="/register" method="post">
<input type="text" placeholder="Username" name="username" required>
<input type="password" placeholder="Password" name="password" required>
<button type="submit">注册</button>
</form>
</div>
</body>
</html>
6.3 登录错误页面
<%--
Created by IntelliJ IDEA.
User: Administrator
Date: 2023/11/28
Time: 21:10
To change this template use File | Settings | File Templates.
--%>
<%--<%@ page contentType="text/html;charset=UTF-8" language="java"%>--%>
<%@ page contentType="text/html; charset=gb2312" language="java" %>
<html lang="en">
<head>
<title>登录失败</title>
</head>
<body>
<h1>登录失败！</h1>
<font color="red">
<%
if(request.getAttribute("message")!= null){
response.setContentType("text/html;charset=UTF-8");
out.print(request.getAttribute("message"));
}
%>
</font>
<br>
<a href="login.jsp">重新登录</a>
</body>
</html>
6.4 登录成功页面
<%@ page import="org.javatop.case01.domain.User" %><%--
Created by IntelliJ IDEA.
User: Administrator
Date: 2023/11/28
Time: 21:10
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=utf-8" language="java" %>
<html lang="en">
<head>
<title>登录成功</title>
</head>
<body>
<h1>登录成功！</h1>
<br>
<font color="red">
<%
User user = (User)request.getAttribute("user");
String username = user.getUsername();
%>
欢迎您：
<%
out.print(username);
%>
</font>
</body>
</html>
6.5 注册成功页面
<%--
Created by IntelliJ IDEA.
User: Administrator
Date: 2023/11/28
Time: 21:10
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html lang="en">
<head>ccccccccccccccccc
<title>注册成功</title>
</head>
<body>
<h1>注册成功！</h1>
<br>
<a href="login.jsp">跳转登录</a>
<a href="register.jsp">继续注册</a>
</body>
7.总结
本篇教程内容比较长，适合初学者学习，但是也需要有一点基础，比如环境的配置，但如果你稍微有点基础，操作一下这篇文章是非常不错的，特别是代码。
8.最后总结
以上便是本文的全部内容，本人才疏学浅，文章有什么错误的地方，欢迎大佬们批评指正！我是Leo，一个在互联网行业的小白，立志成为更好的自己。
如果你想了解更多关于Leo，可以关注公众号-程序员Leo，后面文章会首先同步至公众号。
