<!--        mybaitis 依賴-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>3.0.0</version>
        </dependency>
<!--mysql鏈接依賴-->
        <dependency>
            <groupId>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
            <scope>runtime</scope>
        </dependency>

server:
  port: 8081
spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/user?serverTimezone=GMT%2B8&characterEncoding=utf-8&useSSL=false
    username: root
    password: 200718
mybatis:
  #  mapper映射文件包掃描 (這里是對(duì)應(yīng) resources 的文件路徑)
  mapper-locations: classpath:/mappers/*.xml
  #  實(shí)體類別名包掃描
  type-aliases-package: com.yun.pojo

@AllArgsConstructor
@NoArgsConstructor
@Data
public class User {
    private int id;
    private String username;
    private String password;
}

@SpringBootApplication
@MapperScan("com.example.mybaitis_01.mapper") // 掃描的mapper
public class Mybaitis01Application {
    public static void main(String[] args) {
        SpringApplication.run(Mybaitis01Application.class, args);
    }
}

@Mapper
public interface TestMapper {
    List<String> selectNameAll();
}

<?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.yun.mappers.TestMapper">
    <select id="selectNameAll" resultType="com.yun.pojo.User">
        select * from tb_user
    </select>
</mapper>

@Service
public interface TestService {
    List<String> selectNameAll();
}

@Service
public class TestServiceImpl implements TestService {
    @Autowired
    private TestMapper testMapper;

    @Override
    public List<String> selectNameAll() {
        return testMapper.selectNameAll();
    }
}

@SpringBootTest
class Demo1ApplicationTests {
    @Autowired
    private TestService testService;

    @Test
    void contextLoads() {
        System.out.println(testService.selectNameAll());
    }
}

mybatis:
  configuration:
    map-underscore-to-camel-case: true

mybatis.configuration.map-underscore-to-camel-case=true