一、创建项目

引入 MyBatis FrameWork 、MySQL Driver

二、环境搭建

重点：接口类处 需要引用@Mapper 注解

<dependencies>
  <dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.2.2</version>
  </dependency>
  <dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
  </dependency>
  <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
  </dependency>
  <dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.18.12</version>
  </dependency>
  <!-- https://mvnrepository.com/artifact/com.alibaba/druid -->
  <dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>1.1.10</version>
  </dependency>
</dependencies>

@Data
public class User {
    private Integer id ;
    private String username ;
    private String password ;
    private Integer age ;
    private String sex ;
    private String email ;
}

@Mapper
public interface UserService {
    @Select("select * from tb_user")
    public List<User> getAllUsers();
}

public class UserServiceImpl implements UserService {
    @Autowired
    private UserService userService;
    @Override
    public List<User> getAllUsers() {
        List<User> users = userService.getAllUsers();
        return users;
    }
}

@SpringBootTest
class Demo8MyBatisApplicationTests {
    @Autowired
    private UserService userService;
    @Test
    void testUserService(){
        List<User> users = userService.getAllUsers();
        for (User user : users) {
            System.out.println(user);
        }
    }
}

三、配置连接数据库

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/db_mybatis
    username: root
    password: root
    type: com.alibaba.druid.pool.DruidDataSource

四、创建业务类

@Mapper
public interface UserService {
    @Select("select * from tb_user")
    public List<User> getAllUsers();
}

public class UserServiceImpl implements UserService {
    @Autowired
    private UserService userService;
    @Override
    public List<User> getAllUsers() {
        List<User> users = userService.getAllUsers();
        return users;
    }
}

五、测试