✨ feat: 전역 예외 처리 기능 구현

각 도메인별 Advice에 중복으로 존재하던 예외 처리 로직을 한 곳에서 관리하고, 일관된 에러 응답을 제공하기 위해 전역 예외 처리 기능 개발

주요 변경 사항:
- GlobalExceptionAdvice: @Valid 유효성 검사, IllegalArgumentException 등 애플리케이션 공통 예외를 처리하는 Advice 추가
- ApiCustomExceptionAdvice: 모든 도메인의 비즈니스 예외를 통합 처리하는 Advice 추가
- ErrorCode 인터페이스 및 CustomException 추상 클래스: 모든 커스텀 예외와 에러 코드를 표준화
- ApiResponse: ErrorCode 인터페이스를 받을 수 있는 error() 메소드를 추가

Author: leeseojun34

src/main/java/com/grepp/spring/infra/error/ApiCustomExceptionAdvice.java

@@ -0,0 +1,26 @@
+package com.grepp.spring.infra.error;
+
+import com.grepp.spring.infra.error.exceptions.CustomException;
+import com.grepp.spring.infra.response.ApiResponse;
+import com.grepp.spring.infra.response.error.ErrorCode;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.core.annotation.Order;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+
+@Slf4j
+@RestControllerAdvice(basePackages = "com.grepp.spring.app.controller.api")
+@Order(0)
+public class ApiCustomExceptionAdvice {
+
+    @ExceptionHandler(CustomException.class)
+    public ResponseEntity<ApiResponse<Object>> handleCustomException(CustomException ex) {
+        ErrorCode errorCode = ex.getErrorCode();
+        log.warn("API CustomException occurred: code={}, message={}", errorCode.code(), errorCode.message());
+
+        return ResponseEntity
+            .status(errorCode.status())
+            .body(ApiResponse.error(errorCode));
+    }
+}

src/main/java/com/grepp/spring/infra/error/GlobalExceptionAdvice.java

@@ -0,0 +1,56 @@
+package com.grepp.spring.infra.error;
+
+import com.grepp.spring.infra.response.ApiResponse;
+import com.grepp.spring.infra.response.ResponseCode;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.http.ResponseEntity;
+import org.springframework.validation.BindException;
+import org.springframework.web.bind.MethodArgumentNotValidException;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+
+import java.util.HashMap;
+import java.util.Map;
+
+@Slf4j
+@RestControllerAdvice
+public class GlobalExceptionAdvice {
+
+    @ExceptionHandler({MethodArgumentNotValidException.class, BindException.class})
+    public ResponseEntity<ApiResponse<Map<String, String>>> validationExHandler(BindException ex) {
+        Map<String, String> errors = new HashMap<>();
+        ex.getBindingResult().getFieldErrors().forEach(error -> {
+            String fieldName = error.getField();
+            String errorMessage = error.getDefaultMessage();
+            errors.put(fieldName, errorMessage);
+        });
+        log.warn("Validation error: {}", errors);
+        return ResponseEntity
+            .status(ResponseCode.BAD_REQUEST.status())
+            .body(ApiResponse.error(ResponseCode.BAD_REQUEST, errors));
+    }
+
+    @ExceptionHandler(IllegalArgumentException.class)
+    public ResponseEntity<ApiResponse<String>> illegalArgumentExHandler(IllegalArgumentException ex) {
+        log.warn("Illegal argument: {}", ex.getMessage());
+        return ResponseEntity
+            .status(ResponseCode.BAD_REQUEST.status())
+            .body(ApiResponse.error(ResponseCode.BAD_REQUEST, ex.getMessage()));
+    }
+
+    @ExceptionHandler(IllegalStateException.class)
+    public ResponseEntity<ApiResponse<String>> illegalStateExHandler(IllegalStateException ex) {
+        log.warn("Illegal state: {}", ex.getMessage());
+        return ResponseEntity
+            .status(ResponseCode.BAD_REQUEST.status())
+            .body(ApiResponse.error(ResponseCode.BAD_REQUEST, ex.getMessage()));
+    }
+
+    @ExceptionHandler(Exception.class)
+    public ResponseEntity<ApiResponse<String>> allUncaughtExHandler(Exception ex) {
+        log.error("Unhandled exception", ex);
+        return ResponseEntity
+            .status(ResponseCode.INTERNAL_SERVER_ERROR.status())
+            .body(ApiResponse.error(ResponseCode.INTERNAL_SERVER_ERROR, "서버 내부 오류가 발생했습니다."));
+    }
+}

src/main/java/com/grepp/spring/infra/error/exceptions/CustomException.java

@@ -0,0 +1,19 @@
+package com.grepp.spring.infra.error.exceptions;
+
+import com.grepp.spring.infra.response.error.ErrorCode;
+import lombok.Getter;
+
+@Getter
+public abstract class CustomException extends RuntimeException {
+    private final ErrorCode errorCode;
+
+    public CustomException(ErrorCode errorCode) {
+        super(errorCode.message());
+        this.errorCode = errorCode;
+    }
+
+    public CustomException(ErrorCode errorCode, Exception e) {
+        super(errorCode.message(), e);
+        this.errorCode = errorCode;
+    }
+}

src/main/java/com/grepp/spring/infra/response/ApiResponse.java

@@ -1,5 +1,6 @@
 package com.grepp.spring.infra.response;
 
+import com.grepp.spring.infra.response.error.ErrorCode;
 import io.swagger.v3.oas.annotations.media.Schema;
 
 @Schema(description = "공통 응답 DTO", name = "ApiResponse")
@@ -26,6 +27,10 @@ public static <T> ApiResponse<T> noContent() {
         return new ApiResponse<>(ResponseCode.OK.code(), ResponseCode.OK.message(), null);
     }
 
+    public static <T> ApiResponse<T> error(ErrorCode code) {
+        return new ApiResponse<>(code.code(), code.message(), null);
+    }
+
     public static <T> ApiResponse<T> error(ResponseCode code) {
         return new ApiResponse<>(code.code(), code.message(), null);
     }

src/main/java/com/grepp/spring/infra/response/error/ErrorCode.java

@@ -0,0 +1,9 @@
+package com.grepp.spring.infra.response.error;
+
+import org.springframework.http.HttpStatus;
+
+public interface ErrorCode {
+    String code();
+    HttpStatus status();
+    String message();
+}