springboot-整合mybatis-纯注解法-09

1.创建与数据库对应的bean

public class City {
    private long id;
    private String name;
    private String state;
    private String country;
}

2.创建mapper文件com.atguigu.admin.mapper.CityMapper

@Mapper
@Mapper
public interface CityMapper {

    @Select("select * from city where id = #{id}")
    public City getById(Long id);
}

3.创建与mapper对应的service文件com.atguigu.admin.service.CityService

@Service
public class CityService {
    @Autowired
    CityMapper cityMapper;

    public City getById(Long id){
        return cityMapper.getById(id);
    }
}

4.编写controller中的内容

    @Autowired
    CityService cityService;

    @ResponseBody
    @GetMapping("/city")
    public City getCityById(@RequestParam("id") Long id){
        return cityService.getById(id);
    }