一、 Mapper接口

@Mapper
public interface ApiMapper {
    //#{}有单引号，${}无单引号
    @Insert("insert into tablel (id,name) values (${id},#{name})")
    int insert(int id, String name);
    
    @Select("select name from tablel where id = ( ${id} ) limit 1 ")
    User select(int id);

    @Delete("delete from tablel where name = #{n} ")
    int delete(@Param("n") String name);

    @Update("update tablel set name = #{name} where id = ${id}")
    int update(int id, String name);
}

二、 service

@Service
public class ApiService {
    @Autowired
    ApiMapper apiMapper;

    public String insert(int id, String name) {
        try {
            //若id为主键，且此id已经存在，则会报错
            if (apiMapper.insert(id, name) > 0) {
                return "success";
            } else {
                return "failed";
            }
        } catch (Exception e) {
            return "数据库错误";
        } 
    }

    public User selectById(int id) {
        return apiMapper.select(id);
    }

    public String deleteByName(String name) {
        if (apiMapper.delete(name) > 0) {
            return "success!!";
        } else {
            return "无此name";
        }
    }

    public String update(int id, String name) {
        if(apiMapper.update(id, name)>0){
            return "success!!";
        }else{
            return "failed";
        }
    }
}

三、 controller

@RestController
public class ApiController {

    @Autowired
    ApiService apiService;


    @PostMapping("/insert")
    public String insert(@RequestParam int id,
                         @RequestParam(required = false, defaultValue = "zz") String name) {
        return apiService.insert(id, name);
    }

    @GetMapping("/select")
    public User selectById(@RequestParam(value = "id") int id) {
        return apiService.selectById(id);
    }

    @RequestMapping("/delete")
    public String deleteByName(@RequestParam String name) {
        return apiService.deleteByName(name);
    }

    @RequestMapping("/update")
    public String updateNameById(@RequestParam int id,
                                 @RequestParam String name) {
        return apiService.update(id, name);
    }
}

小配置

  • 驼峰配置
mybatis:
  configuration:
    map-underscore-to-camel-case: true

hhhhh