Custom validation with database

개요

데이터베이스의 값을 사용해서 커스텀 유효성 검사

개발 절차

1. 어노테이션 생성 및 ConstraintValidator 구현체 생성
   kotlin

   ActiveUniqueId.kt

   @Target(AnnotationTarget.FIELD)
   @Retention(AnnotationRetention.RUNTIME)
   @Constraint(validatedBy = [ActiveUniqueIdValidator::class])
   annotation class ActiveUniqueId (
       val message: String = "잘못된 ID입니다.",
       val groups: Array<KClass<*>> = [],
       val payload: Array<KClass<out Payload>> = [],
   )
   
   @Component
   class ActiveUniqueIdValidator(private val uniqueIdMapper: UniqueIdMapper) : ConstraintValidator<ActiveUniqueId, String> {
       override fun isValid(value: String?, context: ConstraintValidatorContext?): Boolean {
           //필수입력 여부는 별도의 NotBlank 어노테이션으로 제약을 설정한다.
           if (value === null || value.isBlank()) {
               return true
           }
           return uniqueIdMapper.selectUniqueIdCnt(value) > 0
       }
   }

   java

   ActiveUniqueId.java

2. 요청 DTO 클래스의 멤버에 제약 설정
   kotlin

   any request dto class

   @field:Schema(description = "ID")
   @field:NotBlank
   @field:ActiveUniqueId
   var uniqueId: String,

   java

   any request dto class

3. Controller 메소드에 Valid(Validated) 어노테이션 추가
   kotlin

   any controller class

   @Operation(summary = "커스텀 유효성 체크 with 데이터베이스 테스트", description = "커스텀 유효성 체크 with 데이터베이스 테스트 API")
   @PostMapping("/custom-validation-with-database-test")
   fun testCustomValidationWithDatabase(@Valid @RequestBody param: CustomValidationWithDatabaseRequestDto): ResponseEntity<ResponseDto<Unit>> {
       log.info("testCustomValidationWithDatabase param: $param")
       return ResponseEntity.status(HttpStatus.CREATED).body((ResponseDto(Unit)))
   }

   java

   any controller class

4. Validation 오류가 발생하면 MethodArgumentNotValidException 예외가 던져지는데, 이 예외가 발생시 405 Bad Request 오류가 발생하도록 설정
   kotlin

   RestApiExceptionAdvice.kt

   @ExceptionHandler(MethodArgumentNotValidException::class)
   @ResponseBody
   fun methodArgumentNotValidExceptionHandler(e: MethodArgumentNotValidException): ResponseEntity<ResponseDto<Unit>> {
       log.error("### MethodArgumentNotValidException occurred", e)
       val anyItem = e.bindingResult.fieldErrors[0]
       return ResponseEntity
           .badRequest()
           .body(ResponseDto(ApiResultCode.WRONG_PARAMETER, String.format("%s (%s)", anyItem.defaultMessage, anyItem.field)))
   }

   java

   RestApiExceptionAdvice.java

   @ExceptionHandler(MethodArgumentNotValidException.class)
   public @ResponseBody ResponseEntity<ResponseDto<Void>> methodArgumentNotValidExceptionHandler(final MethodArgumentNotValidException e) {
       log.error("### MethodArgumentNotValidException Occurred. ID: [{}]", ServletUtil.getRequestAttribute(ServletUtil.X_REQUEST_ID), e);
       return ResponseEntity
           .badRequest()
           .contentType(MediaType.APPLICATION_JSON)
           .body(new ResponseDto<>(ApiResultCode.INVALID_PARAMETER));
   }

5. 테스트
   kotlin

   any test class

   @DisplayName("커스텀 유효성 체크 with 데이터베이스 테스트")
   @Test
   fun `커스텀 유효성 체크 with 데이터베이스 테스트`() {
       val param = CustomValidationWithDatabaseRequestDto("not-unique-id")
       return Given {
           spec(jsonRequestSpecification)
           body(param)
       } When {
           post("/spring-boot/custom-validation-with-database-test")
       } Then {
           statusCode(HttpStatus.SC_BAD_REQUEST)
       } Extract {
           println(body().asString())
       }
   }

   java

   any test class

6. 로그 확인
   kotlin

   2026-02-14 13:56:38,596 [DEBUG] [http-nio-auto-1-exec-3] n.s.l.l.s.Slf4jSpyLogDelegator:  com.zaxxer.hikari.pool.ProxyPreparedStatement.execute(ProxyPreparedStatement.java:44)
   1. /*selectUniqueIdCnt*/
   SELECT COUNT(0) AS CNT
     FROM T_UNIQUE_ID
    WHERE UNIQUE_ID = 'not-unique-id'
      AND USE_YN = 'Y'
   {executed in 1 msec}
   2026-02-14 13:56:38,597 [INFO ] [http-nio-auto-1-exec-3] n.s.l.l.s.Slf4jSpyLogDelegator:
   |----|
   |cnt |
   |----|
   |0   |
   |----|
   
   2026-02-14 13:56:38,604 [ERROR] [http-nio-auto-1-exec-3] b.m.c.c.e.a.RestApiExceptionAdvice: ### MethodArgumentNotValidException occurred
   org.springframework.web.bind.MethodArgumentNotValidException: Validation failed for argument [0] in public org.springframework.http.ResponseEntity<biz.mintchoco.carrot.common.dto.ResponseDto<kotlin.Unit>> biz.mintchoco.carrot.api.spring_boot.controller.SpringBootController.testCustomValidationWithDatabase(biz.mintchoco.carrot.api.spring_boot.dto.CustomValidationWithDatabaseRequestDto): [Field error in object 'customValidationWithDatabaseRequestDto' on field 'uniqueId': rejected value [not-unique-id]; codes [ActiveUniqueId.customValidationWithDatabaseRequestDto.uniqueId,ActiveUniqueId.uniqueId,ActiveUniqueId.java.lang.String,ActiveUniqueId]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [customValidationWithDatabaseRequestDto.uniqueId,uniqueId]; arguments []; default message [uniqueId]]; default message [잘못된 ID입니다.]]
   ...
   at java.base/java.lang.Thread.run(Thread.java:1583)
   {"payload":null,"isSuccess":false,"resultCode":"WRONG_PARAMETER","message":"잘못된 ID입니다. (uniqueId)"}

   java