feat: 공통 예외 응답 클래스(ApiErrorResponse) 및 에러 코드 기반 구조 생성

Author: dnzp75

src/main/java/com/example/log4u/common/exception/ApiErrorResponse.java

@@ -0,0 +1,29 @@
+package com.example.log4u.common.exception;
+
+import java.util.List;
+
+import org.springframework.validation.FieldError;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+
+import lombok.Builder;
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+@Getter
+@Builder
+@RequiredArgsConstructor
+public class ApiErrorResponse {
+	private final String errorMessage;
+	private final int errorCode;
+
+	@JsonInclude(JsonInclude.Include.NON_EMPTY)
+	private final List<ValidationError> errors;
+
+	public record ValidationError(String field, String message) {
+
+		public static ValidationError of(final FieldError fieldError) {
+			return new ValidationError(fieldError.getField(), fieldError.getDefaultMessage());
+		}
+	}
+}

src/main/java/com/example/log4u/common/exception/CommonErrorCode.java

@@ -0,0 +1,33 @@
+package com.example.log4u.common.exception;
+
+import org.springframework.http.HttpStatus;
+
+import com.example.log4u.common.exception.base.ErrorCode;
+
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+@Getter
+@RequiredArgsConstructor
+public enum CommonErrorCode implements ErrorCode {
+
+    INVALID_PARAMETER(HttpStatus.BAD_REQUEST, "잘못된 요청입니다"),
+    UNAUTHENTICATED(HttpStatus.UNAUTHORIZED,"로그인이 필요한 기능입니다."),
+    FORBIDDEN(HttpStatus.FORBIDDEN, "접근 권한이 없습니다"),
+    RESOURCE_NOT_FOUND(HttpStatus.NOT_FOUND, "요청 정보를 찾을 수 없습니다"),
+    INTERNAL_SERVER_ERROR(HttpStatus.INTERNAL_SERVER_ERROR, "서버 내부 오류입니다. 관리자에게 문의하세요.")
+    ;
+
+    private final HttpStatus httpStatus;
+    private final String message;
+
+    @Override
+    public HttpStatus getHttpStatus() {
+        return this.httpStatus;
+    }
+
+    @Override
+    public String getErrorMessage() {
+        return this.message;
+    }
+}