[오류 처리 개선] - ApiException 및 ApiResponseCode 추가, GlobalExceptionHandler에서 ApiException 처리 로직 구현, README에 오류 등록 및 사용 방법 문서화

README.md

@@ -78,3 +78,30 @@ public class MemberServiceImpl {
 - **클래스 레벨**: `@Transactional(readOnly = true)` 기본 설정
 - **메서드별**: 데이터 수정 시에만 `@Transactional` 개별 적용
 - **설정**: `spring.jpa.open-in-view=false` (성능 최적화)
+
+### 4. 오류 등록 및 사용
+
+#### 오류 코드 등록
+
+```java
+// ApiResponseCode.java
+public enum ApiResponseCode {
+    USER_ID_DUPLICATE("400", "이미 존재하는 사용자 ID입니다."),
+}
+```
+
+#### 오류 사용 방법
+
+```java
+// Service에서 예외 발생
+throw new ApiException(ApiResponseCode.USER_ID_DUPLICATE);
+
+// Controller에서 예외 처리 (자동)
+// GlobalExceptionHandler가 ApiException을 잡아서 응답 변환
+```
+
+#### 핵심 규칙
+
+- **오류 코드**: `ApiResponseCode` enum에 모든 오류 정의
+- **예외 클래스**: `ApiException`으로 비즈니스 로직 예외 처리
+- **자동 처리**: `GlobalExceptionHandler`가 일관된 응답 형태로 변환

src/main/java/com/bio/bio_backend/domain/user/member/service/MemberServiceImpl.java

@@ -6,6 +6,8 @@ import com.bio.bio_backend.domain.user.member.enums.MemberRole;
 import com.bio.bio_backend.domain.user.member.mapper.MemberMapper;
 import com.bio.bio_backend.domain.user.member.repository.MemberRepository;
 import com.bio.bio_backend.domain.user.member.exception.UserDuplicateException;
+import com.bio.bio_backend.global.exception.ApiException;
+import com.bio.bio_backend.global.utils.ApiResponseCode;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.security.core.userdetails.UserDetails;
@@ -46,7 +48,7 @@ public class MemberServiceImpl implements MemberService {
     public MemberDto createMember(MemberDto memberDTO) {
         // userId 중복 체크
         if (memberRepository.existsByUserId(memberDTO.getUserId())) {
-            throw new UserDuplicateException("User ID already exists");
+            throw new ApiException(ApiResponseCode.USER_ID_DUPLICATE);
         }
         
         Member member = Member.builder()

src/main/java/com/bio/bio_backend/global/exception/ApiException.java

@@ -0,0 +1,24 @@
+package com.bio.bio_backend.global.exception;
+
+import lombok.Getter;
+import com.bio.bio_backend.global.utils.ApiResponseCode;
+
+@Getter
+public class ApiException extends RuntimeException {
+    private final ApiResponseCode responseCode;
+
+    public ApiException(ApiResponseCode responseCode) {
+        super(responseCode.getDescription());
+        this.responseCode = responseCode;
+    }
+
+    public ApiException(ApiResponseCode responseCode, String message) {
+        super(message);
+        this.responseCode = responseCode;
+    }
+
+    public ApiException(ApiResponseCode responseCode, Throwable cause) {
+        super(responseCode.getDescription(), cause);
+        this.responseCode = responseCode;
+    }
+}

src/main/java/com/bio/bio_backend/global/exception/GlobalExceptionHandler.java

@@ -6,6 +6,7 @@ import org.springframework.http.converter.HttpMessageNotReadableException;
 import org.springframework.web.HttpRequestMethodNotSupportedException;
 import org.springframework.web.bind.annotation.ExceptionHandler;
 import org.springframework.web.bind.annotation.RestControllerAdvice;
+import org.springframework.web.bind.MethodArgumentNotValidException;
 import org.springframework.web.servlet.resource.NoResourceFoundException;
 
 import com.fasterxml.jackson.core.JsonProcessingException;
@@ -73,8 +74,32 @@ public class GlobalExceptionHandler {
         return CustomApiResponse.fail(ApiResponseCode.JSON_PROCESSING_EXCEPTION, null);
     }
     
-    @ExceptionHandler(UserDuplicateException.class)
-    public CustomApiResponse<Void> handleUserDuplicateException(UserDuplicateException e) {
-        return CustomApiResponse.fail(ApiResponseCode.USER_ID_DUPLICATE, null);
+    @ExceptionHandler(ApiException.class)
+    public CustomApiResponse<Void> handleApiException(ApiException e) {
+        return CustomApiResponse.fail(e.getResponseCode(), null);
+    }
+    
+    @ExceptionHandler(MethodArgumentNotValidException.class)
+    public CustomApiResponse<Object> handleMethodArgumentNotValidException(MethodArgumentNotValidException e) {
+        // 검증 실패한 필드들의 상세 오류 정보 추출
+        var errors = e.getBindingResult().getFieldErrors().stream()
+            .map(error -> new ValidationError(error.getField(), error.getDefaultMessage()))
+            .toList();
+        
+        return CustomApiResponse.fail(ApiResponseCode.ARGUMENT_NOT_VALID, errors);
+    }
+    
+    // 검증 오류 상세 정보를 위한 내부 클래스
+    private static class ValidationError {
+        private final String field;
+        private final String message;
+        
+        public ValidationError(String field, String message) {
+            this.field = field;
+            this.message = message;
+        }
+        
+        public String getField() { return field; }
+        public String getMessage() { return message; }
     }
 }

src/main/java/com/bio/bio_backend/global/utils/ApiResponseCode.java

@@ -11,44 +11,30 @@ import org.springframework.http.HttpStatus;
 @Getter
 @AllArgsConstructor
 public enum ApiResponseCode {
-
-    /*login & logout*/
-
+    
     // 200 OK
     LOGIN_SUCCESSFUL(HttpStatus.OK.value(), "Login successful"),
-
     LOGOUT_SUCCESSFUL(HttpStatus.OK.value(), "Logout successful"),
-
     USER_INFO_CHANGE(HttpStatus.OK.value(), "User info update successful"),
-
     USER_DELETE_SUCCESSFUL(HttpStatus.OK.value(),  "User delete is successful"),
 
-    // 401 Unauthorized
-    USER_NOT_FOUND(HttpStatus.UNAUTHORIZED.value(), "User not found. Authentication failed"),
-
-    AUTHENTICATION_FAILED(HttpStatus.UNAUTHORIZED.value(), "Password is invalid"),
-
     // 409 Conflict
     USER_ID_DUPLICATE(HttpStatus.CONFLICT.value(), "User ID already exists"),
 
-    /*auth*/
-    // 401 Unauthorized
-    JWT_SIGNATURE_MISMATCH(HttpStatus.UNAUTHORIZED.value(), "JWT signature does not match. Authentication failed"),
-
-    JWT_TOKEN_NULL(HttpStatus.UNAUTHORIZED.value(), "JWT token is null"),
-
-    JWT_TOKEN_EXPIRED(HttpStatus.UNAUTHORIZED.value(), "Token is Expired"),
-
-    All_TOKEN_INVALID(HttpStatus.UNAUTHORIZED.value(), "Access and Refresh tokens are expired or invalid"),
-
     /*공통 Code*/
     // 400 Bad Request
     COMMON_BAD_REQUEST(HttpStatus.BAD_REQUEST.value(), "Required request body is missing or Error"),
-
     COMMON_FORMAT_WRONG(HttpStatus.BAD_REQUEST.value(), "Request format is incorrect"),
+    ARGUMENT_NOT_VALID(HttpStatus.BAD_REQUEST.value(), "Argument is not valid"),
 
     // 401 Unauthorized
     COMMON_UNAUTHORIZED(HttpStatus.UNAUTHORIZED.value(), "Unauthorized"),
+    USER_NOT_FOUND(HttpStatus.UNAUTHORIZED.value(), "User not found. Authentication failed"),
+    AUTHENTICATION_FAILED(HttpStatus.UNAUTHORIZED.value(), "Password is invalid"),
+    JWT_SIGNATURE_MISMATCH(HttpStatus.UNAUTHORIZED.value(), "JWT signature does not match. Authentication failed"),
+    JWT_TOKEN_NULL(HttpStatus.UNAUTHORIZED.value(), "JWT token is null"),
+    JWT_TOKEN_EXPIRED(HttpStatus.UNAUTHORIZED.value(), "Token is Expired"),
+    All_TOKEN_INVALID(HttpStatus.UNAUTHORIZED.value(), "Access and Refresh tokens are expired or invalid"),
 
     // 403 Forbidden
     COMMON_FORBIDDEN(HttpStatus.FORBIDDEN.value(), "Access is denied"),
@@ -61,11 +47,7 @@ public enum ApiResponseCode {
 
     // 500 Internal Server Error
     INTERNAL_SERVER_ERROR(HttpStatus.INTERNAL_SERVER_ERROR.value(), "An error occurred on the server"),
-
-    ARGUMENT_NOT_VALID(HttpStatus.INTERNAL_SERVER_ERROR.value(), "Argument is not valid"),
-
     INDEX_OUT_OF_BOUND(HttpStatus.INTERNAL_SERVER_ERROR.value(), "Index out of bounds for length"),
-	
 	JSON_PROCESSING_EXCEPTION(HttpStatus.INTERNAL_SERVER_ERROR.value(), "Check if it is a valid JSON format");
 
     private final int statusCode;