首先搭建环境，idea+mySQL+mybatis+springBoot创建的demo。

配置文件

在resources目录下application.yml文件中

#端口
server:
  port: 8080

#连接本地数据库
spring:
  datasource:
    url: jdbc:mysql://localhost:3306/student_table?useUnicode=true&amp&characterEncoding=utf-8&amp&serverTimezone=UTC #注意设置编码格式
    username: root
    password: *****

#配置mybatis 该配置节点为独立的节点
mybatis:
  mapper-locations: classpath:mybatis/*.xml  # 注意:一定要对应mapper映射xml文件的所在路径
  type-aliases-package: com.zjh.api.demo.entity  # 注意:对应实体类的路径
  configuration:
    map-underscore-to-camel-case: true # 数据库字段下划线自动转驼峰

然后创建一个mybatis文件夹，再在下面创建UserMapper.xml文件，返回数据类型和sql语句

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.zjh.api.demo.mapper.UserMapper">
    <select id="getUserInfo" resultType="com.zjh.api.demo.entity.UserEntity">
            select * from student where teacherId = 1
    </select>
</mapper>

创建entity文件夹，创建UserEntity文件

@JsonInclude(JsonInclude.Include.NON_NULL)
public class UserEntity {
    public String name;
    public int year;
    public int teacherId;
}

创建mapper文件夹，创建UserMapper类

@Repository
public interface UserMapper {
    //获取用户信息
    List<UserEntity> getUserInfo();
}

创建service文件夹，创建UserService类

@Repository
public class UserService {

    @Autowired
    UserMapper mMapper;

    public List<UserEntity> getUserInfo(){
        return mMapper.getUserInfo();
    }
}

创建controller文件夹，创建UserController文件

@RestController
public class UserController {

    @Autowired
    private UserService mUserService;

    @RequestMapping(value = "/getUserInfo", method = RequestMethod.GET)
    public BaseEntity getUserInfo() {
        List<UserEntity> userList = mUserService.getUserInfo();
        Map<String, Object> map = new HashMap<>();
        map.put("student", userList);
        if (userList != null) {
            return BaseEntity.success(map);
        }
        return new BaseEntity().setMsg("请求失败").setState(201);
    }
}