[Kotlin + Spring Boot + SpringDataJPA + H2 + Gradle] 4. @Valid를 사용한 REST API validation 처리

의존성 추가

build.gradle dependencies 안에 아래 코드 추가

implementation("org.springframework.boot:spring-boot-starter-validation")

 

build.gradle.kt

plugins {
	id("org.springframework.boot") version "3.4.2"
	id("io.spring.dependency-management") version "1.1.7"
	id("java")
	id("org.jetbrains.kotlin.jvm") version "1.9.25"
	id("org.jetbrains.kotlin.plugin.jpa") version "1.9.25"
	id("org.jetbrains.kotlin.plugin.spring") version "1.9.25"
	id("org.jetbrains.kotlin.kapt") version "1.9.25"
}

group = "com.contact"
version = "0.0.1-SNAPSHOT"

java {
	toolchain {
		languageVersion.set(JavaLanguageVersion.of(17))
	}
}

repositories {
	mavenCentral()
}

dependencies {
	implementation("org.springframework.boot:spring-boot-starter-data-jpa")
	implementation("org.springframework.boot:spring-boot-starter-web")
	implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
	implementation("org.jetbrains.kotlin:kotlin-reflect")
	implementation("com.fasterxml.jackson.module:jackson-module-kotlin")
	implementation("org.springframework.boot:spring-boot-starter-validation")
	runtimeOnly("com.h2database:h2")
	testImplementation("org.springframework.boot:spring-boot-starter-test")
}

tasks.withType<Test> {
	useJUnitPlatform()
}

tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile> {
	kotlinOptions {
		jvmTarget = "17"
	}
}

 

UserDto.kt

package com.contact.management.dto

import jakarta.validation.constraints.Email
import jakarta.validation.constraints.Size

data class UserDto(
    val id: Long?= null,

    @field:Size(min = 2, max = 50, message = "이름은 2~50자 사이여야 합니다.")
    val name: String,

    @field:Email(message = "올바른 이메일 형식을 입력하세요.")
    val email: String
)

 

GlobalExceptionHandler.kt

package com.contact.management.exception

import org.springframework.http.HttpStatus
import org.springframework.http.ResponseEntity
import org.springframework.web.bind.MethodArgumentNotValidException
import org.springframework.web.bind.annotation.ExceptionHandler
import org.springframework.web.bind.annotation.RestControllerAdvice

@RestControllerAdvice
class GlobalExceptionHandler {

    @ExceptionHandler(CommonException::class)
    fun handleCommonException(e: CommonException): ResponseEntity<ErrorResponse> {
        val errorResponse = ErrorResponse(
            status = e.exceptionCode.status.value(),
            error = e.exceptionCode.message,
            message = e.message ?: "예외 발생"
        )
        return ResponseEntity(errorResponse, e.exceptionCode.status)
    }

    @ExceptionHandler(MethodArgumentNotValidException::class)
    fun handleValidationExceptions(ex: MethodArgumentNotValidException): ResponseEntity<ErrorResponse> {
        val errors = ex.bindingResult.fieldErrors.associate { it.field to (it.defaultMessage ?: "잘못된 값") }

        val errorResponse = ErrorResponse(
            status = HttpStatus.BAD_REQUEST.value(),
            error = "Validation Failed",
            message = "입력값이 올바르지 않습니다.",
            errors = errors
        )

        return ResponseEntity(errorResponse, HttpStatus.BAD_REQUEST)
    }
}

 

-> handlerValdationExceptions를 추가함, vadliation에 걸렸을때 errorResponse에 400 BAD_REQUEST, 에러 내용을 return 하게 설정함

 

UserController.kt

package com.contact.management.controller

import com.contact.management.dto.UserDto
import com.contact.management.service.UserService
import jakarta.validation.Valid
import org.springframework.http.HttpHeaders
import org.springframework.http.HttpStatus
import org.springframework.http.ResponseEntity
import org.springframework.web.bind.annotation.*

@RestController
@RequestMapping("/api/users")
class UserController(
    private val userService: UserService
) {

    @GetMapping
    fun getUsers(): ResponseEntity<List<UserDto>> {
        val users = userService.getAllUsers()
        return ResponseEntity.ok(users)
    }

    @GetMapping("/{id}")
    fun getUser(@PathVariable id: Long): ResponseEntity<UserDto> {
        return ResponseEntity.ok(userService.getUserById(id))
    }

    @PostMapping
    fun createUser(@Valid @RequestBody userDto: UserDto): ResponseEntity<UserDto> {
        val createdUser = userService.createdUser(userDto)
        return ResponseEntity
            .status(HttpStatus.CREATED) // 201 Created
            .header(HttpHeaders.LOCATION, "/api/users/${createdUser.id}") // 생성된 리소스의 URI 반환
            .body(createdUser)
    }

    @PutMapping("/{id}")
    fun updateUser(@PathVariable id: Long,@Valid @RequestBody userDto: UserDto): ResponseEntity<UserDto> {
        val updatedUser = userService.updateUser(id, userDto)
        return ResponseEntity.ok(updatedUser)
    }

    @DeleteMapping("/{id}")
    fun deleteUser(@PathVariable id: Long): ResponseEntity<Void> {
        userService.deleteUser(id)
        return ResponseEntity.noContent().build() // 204 No Content
    }
}

 

 

-> createUser, updateUser api에 @Valid를 추가

 

이름 길이가 2~50자가 아닌경우

 

이메일 형식을 벗어난 경우

 

 

만약 GlobalException에 handleValidationExceptions를 적용하지않았다면

-> GlobalExcpetionHandler에 등록했을때와 비교했을때 에러 메시지가 부족