Spring Boot + MyBatis :登录注册功能

个人博客：[http://wj2y.cn/]

1. 编写实体类

用户登录注册这里做的比较简单，只做了用户名和密码，所以实体类User.java中只需要username、password两个变量。该类中只需要快速生成有参和无参、get和set方法、最后加一个toString方法。

public class User {private String username;private String password;public User() {}public User(String username, String password) {this.username = username;this.password = password;}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;}@Overridepublic String toString() {return "User{" +"username='" + username + '\'' +", password='" + password + '\'' +'}';}
}

2. 编写UserMapper接口

在mapper下创建一个 UserMapper 接口，该接口主要写查询、增加方法。

import com.wangjun.pojo.User;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.RequestParam;
import java.util.List;@Mapper
@Component
public interface UserMapper {//通过账号密码来查询信息List<User> queryUserByUp(@RequestParam("username") String username, @RequestParam("password") String password);//查询所有用户List<User> queryUserList();//增加用户int addUser(@RequestParam("user") User user);//通过用户名来进行查询List<User> queryUserByUserName(@RequestParam("username") String username);}

3. 编写 UserMapper .xml

在resources下创建mybatis文件夹再创建一个mapper文件夹，在mapper文件夹下创建UserMapper .xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.wangjun.mapper.UserMapper"><select id="queryUserByUp" resultType="User">select * from user where username = #{username} AND password = #{password}</select><select id="queryUserList" resultType="User">select * from user</select><select id="queryUserByUserName" resultType="User">select * from user where username = #{username}</select><insert id="addUser" parameterType="User">insert into user (username,password) values (#{username},#{password})</insert></mapper>

PS： namespace必须是UserMapper的完整路径。

、标签中的id必须和接口中方法名保持一致。

4. 编写Controller类

4.1 编写登录控制类（LoginController）

逻辑：利用从前端获取过来的用户名和密码进行查询，如果查询到数据，就成功登录。反之，登录失败给出提示信息。

PS：没有把包复制在下面代码中，要用的自己直接导入就可以了~

@Controller
public class LoginController {@AutowiredUserMapper userMapper;@RequestMapping("/login")public String login(@RequestParam("username") String username,@RequestParam("password") String password,Model model, HttpSession session){//用从前端获取的username、password进行查询List<User> user1 = userMapper.queryUserByUp(username,password);if (!user1.isEmpty()){session.setAttribute("loginUser",username);return "redirect:/main.html";}else {model.addAttribute("msg","用户名或者密码错误");return "index";}}}

4.2 编写注册控制类（RegisController）

逻辑：通过前端输入的用户名查询数据库中是否存在，存在则给出提示信息，反之，保存用户名和密码并且直接成功登录到后台。

PS：没有把包复制在下面代码中，要用的自己直接导入就可以了~

@Controller
public class RegisController {@AutowiredUserMapper userMapper;@RequestMapping("/regis")public String regis(@RequestParam("username") String username,@RequestParam("password") String password,Model model,HttpSession session){User user = new User();List<User> user1 = userMapper.queryUserByUserName(username);if (!user1.isEmpty()){model.addAttribute("msg","用户名存在");return "regis";} else {//保存输入的用户名和密码user.setUsername(username);user.setPassword(password);userMapper.addUser(user);session.setAttribute("loginUser",username);return "redirect:/main.html";}}
}

5. 前端页面

前端页面很简单，只需要确保用户名和密码输入框中的name和变量名一致，这里就不贴代码了~

6. application.properties

spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.url=jdbc:mysql://localhost:3306/数据库名?serverTimezone=UTC&useUnicode=true$characterEncoding=utf-8
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver#整合mybatis
mybatis.type-aliases-package=com.wangjun.pojo
mybatis.mapper-locations=classpath:mybatis/mapper/*.xml

7. 导入的依赖

<dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-configuration-processor</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-thymeleaf</artifactId></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId></dependency><dependency><groupId>org.mybatis.spring.boot</groupId><artifactId>mybatis-spring-boot-starter</artifactId><version>2.1.1</version></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-jdbc</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-validation</artifactId></dependency><dependency><groupId>org.webjars</groupId><artifactId>jquery</artifactId><version>3.4.1</version></dependency><!--lombok--><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId></dependency></dependencies>

8. 总结

这个顺序不是写代码的顺序哈，只是我在写博客时没有注意到顺序的问题，写项目那肯定是先导入依赖的哈，结果我却放在了最后，不过依赖应该都是小问题！

其实登录注册功能不难，代码也比较简单，好好看看理解一下秒懂的~