[ENHANCEMENT] 타임존 처리 KST로 통일

src/main/java/ditda/backend/BackendApplication.java

@@ -1,5 +1,7 @@
 package ditda.backend;
 
+import java.util.TimeZone;
+
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.boot.context.properties.ConfigurationPropertiesScan;
@@ -15,6 +17,9 @@
 public class BackendApplication {
 
 	public static void main(String[] args) {
+
+		TimeZone.setDefault(TimeZone.getTimeZone("Asia/Seoul"));
+
 		SpringApplication.run(BackendApplication.class, args);
 	}
 

src/main/java/ditda/backend/domain/auth/service/DesignerAuthService.java

@@ -1,7 +1,6 @@
 package ditda.backend.domain.auth.service;
 
 import java.time.LocalDateTime;
-import java.time.ZoneId;
 import java.util.List;
 
 import org.springframework.context.ApplicationEventPublisher;
@@ -28,7 +27,6 @@
 public class DesignerAuthService {
 
 	private static final String DEFAULT_PROFILE_IMAGE = "profile/default.png";
-	private static final ZoneId ZONE_KST = ZoneId.of("Asia/Seoul");
 
 	private final DesignerRepository designerRepository;
 	private final UserService userService;
@@ -82,7 +80,7 @@ public AuthResult signup(DesignerSignupRequest request, List<String> portfolioKe
 			user.getName(),
 			user.getEmail(),
 			!portfolioKeys.isEmpty(),
-			LocalDateTime.now(ZONE_KST)
+			LocalDateTime.now()
 		));
 
 		return new AuthResult(

src/main/java/ditda/backend/domain/commission/application/facade/DesignerApplicationFacade.java

@@ -2,7 +2,6 @@
 
 import java.time.LocalDate;
 import java.time.LocalDateTime;
-import java.time.ZoneId;
 import java.util.List;
 
 import org.springframework.context.ApplicationEventPublisher;
@@ -29,8 +28,6 @@
 @RequiredArgsConstructor
 public class DesignerApplicationFacade {
 
-	private static final ZoneId ZONE_KST = ZoneId.of("Asia/Seoul");
-
 	private final CommissionService commissionService;
 	private final DesignerService designerService;
 	private final ApplicationService applicationService;
@@ -123,7 +120,7 @@ private void publishMatchedEvent(Commission commission, List<CommissionApplicati
 			commission.getDesignerCount(),
 			selected.size(),
 			commission.getFirstDraftDeadline(),
-			LocalDateTime.now(ZONE_KST),
+			LocalDateTime.now(),
 			toDesignerMatchInfos(selected)
 		));
 	}

src/main/java/ditda/backend/domain/commission/core/dto/response/CommissionCreateResponse.java

@@ -37,7 +37,7 @@ public record CommissionCreateResponse(
 	@Schema(description = "최대 수정 횟수", example = "3")
 	int maxRevision,
 
-	@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd HH:mm:ss", timezone = "Asia/Seoul")
+	@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd HH:mm:ss")
 	LocalDateTime createdAt
 ) {
 

src/main/java/ditda/backend/domain/commission/core/service/CommissionDeadlineService.java

@@ -2,7 +2,6 @@
 
 import java.time.LocalDate;
 import java.time.LocalDateTime;
-import java.time.ZoneId;
 import java.util.List;
 import java.util.Set;
 
@@ -23,7 +22,6 @@
 public class CommissionDeadlineService {
 
 	private static final int MAIL_DISPATCH_HOUR = 9;
-	private static final ZoneId ZONE_KST = ZoneId.of("Asia/Seoul");
 
 	private final CommissionRepository commissionRepository;
 	private final ApplicationDeadlineProcessor applicationDeadlineProcessor;
@@ -32,7 +30,7 @@ public class CommissionDeadlineService {
 
 	public void processApplicationDeadlines() {
 
-		LocalDate today = LocalDate.now(ZONE_KST);
+		LocalDate today = LocalDate.now();
 
 		// 메일 전송 시간
 		LocalDateTime mailScheduledAt = today.atTime(MAIL_DISPATCH_HOUR, 0);
@@ -56,7 +54,7 @@ public void processApplicationDeadlines() {
 
 	public void processFirstDraftDeadlines() {
 
-		LocalDate today = LocalDate.now(ZONE_KST);
+		LocalDate today = LocalDate.now();
 
 		// 메일 전송 시간
 		LocalDateTime mailScheduledAt = today.atTime(MAIL_DISPATCH_HOUR, 0);
@@ -80,7 +78,7 @@ public void processFirstDraftDeadlines() {
 
 	public void processFinalDeadlines() {
 
-		LocalDate today = LocalDate.now(ZONE_KST);
+		LocalDate today = LocalDate.now();
 
 		// 메일 전송 시간
 		LocalDateTime mailScheduledAt = today.atTime(MAIL_DISPATCH_HOUR, 0);

src/main/java/ditda/backend/domain/commission/draft/dto/response/DraftSelectResponse.java

@@ -22,7 +22,7 @@ public record DraftSelectResponse(
 	@Schema(description = "남은 수정 횟수", example = "3")
 	int remainingRevisionCount,
 
-	@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd HH:mm:ss", timezone = "Asia/Seoul")
+	@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd HH:mm:ss")
 	LocalDateTime selectedAt
 
 ) {

src/main/java/ditda/backend/domain/commission/draft/dto/response/DraftSubmitResponse.java

@@ -16,7 +16,7 @@ public record DraftSubmitResponse(
 	Long draftId,
 
 	@Schema(description = "제출 시각", example = "2026-05-15 12:30:00")
-	@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd HH:mm:ss", timezone = "Asia/Seoul")
+	@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd HH:mm:ss")
 	LocalDateTime submittedAt
 ) {
 

src/main/java/ditda/backend/domain/commission/draft/facade/DesignerDraftFacade.java

@@ -1,7 +1,6 @@
 package ditda.backend.domain.commission.draft.facade;
 
 import java.time.LocalDateTime;
-import java.time.ZoneId;
 import java.util.List;
 
 import org.springframework.context.ApplicationEventPublisher;
@@ -27,8 +26,6 @@
 @RequiredArgsConstructor
 public class DesignerDraftFacade {
 
-	private static final ZoneId ZONE_KST = ZoneId.of("Asia/Seoul");
-
 	private final CommissionService commissionService;
 	private final DesignerDraftService designerDraftService;
 	private final DesignerDraftFileService designerDraftFileService;
@@ -111,7 +108,7 @@ private void publishAllFirstDraftsSubmittedEvent(Long commissionId) {
 			commission.getInstructor().getUser().getEmail(),
 			commission.getInstructor().getName(),
 			(int)submittedCount,
-			LocalDateTime.now(ZONE_KST)
+			LocalDateTime.now()
 		));
 
 		log.info("모든 1차 시안 제출 완료. commissionId={}, submittedCount={}",

src/main/java/ditda/backend/domain/commission/draft/facade/InstructorDraftFacade.java

@@ -1,7 +1,6 @@
 package ditda.backend.domain.commission.draft.facade;
 
 import java.time.LocalDateTime;
-import java.time.ZoneId;
 import java.util.List;
 
 import org.springframework.context.ApplicationEventPublisher;
@@ -31,8 +30,6 @@
 @RequiredArgsConstructor
 public class InstructorDraftFacade {
 
-	private static final ZoneId ZONE_KST = ZoneId.of("Asia/Seoul");
-
 	private final InstructorCommissionService instructorCommissionService;
 	private final InstructorDraftService instructorDraftService;
 	private final DraftQueryService draftQueryService;
@@ -71,7 +68,7 @@ public DraftSelectResponse selectDraft(Long instructorId, Long commissionId, Lon
 		applyDesignerSelection(commission, applications, selected, now);
 
 		// 이벤트 발행
-		LocalDateTime mailScheduledAt = LocalDateTime.now(ZONE_KST);
+		LocalDateTime mailScheduledAt = LocalDateTime.now();
 		publishRejectedPayoutEvent(commission, rejected, mailScheduledAt);
 		publishDraftSelectedEvent(commission, selected, rejected, mailScheduledAt);
 
@@ -193,7 +190,7 @@ public void finalizeDraft(Long instructorId, Long commissionId, Long draftId) {
 		Designer assigned = latestDraft.getCommissionApplication().getDesigner();
 		assigned.gainCommissionCompletedReward();
 
-		LocalDateTime mailScheduledAt = LocalDateTime.now(ZONE_KST);
+		LocalDateTime mailScheduledAt = LocalDateTime.now();
 
 		publishPayoutRequestedEvent(commission, assigned, mailScheduledAt);
 		publishCommissionCompletedEvent(commission, assigned, mailScheduledAt);

src/main/java/ditda/backend/domain/commission/revision/facade/DesignerRevisionFacade.java

@@ -1,7 +1,6 @@
 package ditda.backend.domain.commission.revision.facade;
 
 import java.time.LocalDateTime;
-import java.time.ZoneId;
 import java.util.List;
 
 import org.springframework.context.ApplicationEventPublisher;
@@ -38,8 +37,6 @@
 @Slf4j
 public class DesignerRevisionFacade {
 
-	private static final ZoneId ZONE_KST = ZoneId.of("Asia/Seoul");
-
 	private final DesignerCommissionService designerCommissionService;
 	private final DraftQueryService draftQueryService;
 	private final RevisionQueryService revisionQueryService;
@@ -160,7 +157,7 @@ private void publishRevisionSubmittedEvent(Commission commission, int currentRev
 			commission.getInstructor().getUser().getEmail(),
 			commission.getInstructor().getName(),
 			currentRevisionCount,
-			LocalDateTime.now(ZONE_KST)
+			LocalDateTime.now()
 		));
 	}
 }

src/main/java/ditda/backend/domain/commission/revision/facade/InstructorRevisionFacade.java

@@ -1,7 +1,6 @@
 package ditda.backend.domain.commission.revision.facade;
 
 import java.time.LocalDateTime;
-import java.time.ZoneId;
 
 import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.stereotype.Component;
@@ -28,8 +27,6 @@
 @Transactional(readOnly = true)
 public class InstructorRevisionFacade {
 
-	private static final ZoneId ZONE_KST = ZoneId.of("Asia/Seoul");
-
 	private final InstructorCommissionService instructorCommissionService;
 	private final RevisionQueryService revisionQueryService;
 	private final InstructorRevisionService instructorRevisionService;
@@ -128,7 +125,7 @@ private void publishRevisionRequestedEvent(Commission commission, int currentRev
 			designerUser.getEmail(),
 			designerUser.getName(),
 			currentRevisionCount,
-			LocalDateTime.now(ZONE_KST)
+			LocalDateTime.now()
 		));
 	}
 }

src/main/java/ditda/backend/domain/payment/dto/response/DepositNotifyResponse.java

@@ -17,7 +17,7 @@ public record DepositNotifyResponse(
 	PaymentStatus status,
 
 	@Schema(description = "입금 통보 시각", example = "2026-05-26 15:30:00")
-	@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd HH:mm:ss", timezone = "Asia/Seoul")
+	@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd HH:mm:ss")
 	LocalDateTime depositNotifiedAt
 ) {
 

src/main/java/ditda/backend/domain/payment/service/PaymentService.java

@@ -1,7 +1,6 @@
 package ditda.backend.domain.payment.service;
 
 import java.time.LocalDateTime;
-import java.time.ZoneId;
 import java.util.Collection;
 import java.util.Map;
 import java.util.Objects;
@@ -27,8 +26,6 @@
 @RequiredArgsConstructor
 public class PaymentService {
 
-	private static final ZoneId ZONE_KST = ZoneId.of("Asia/Seoul");
-
 	private final PaymentRepository paymentRepository;
 	private final ApplicationEventPublisher eventPublisher;
 	private final TermService termService;
@@ -80,7 +77,7 @@ public DepositNotifyResponse notifyDeposit(Long instructorId, Long commissionId)
 			payment.getDepositorName(),
 			payment.getAmount(),
 			payment.getDepositNotifiedAt(),
-			LocalDateTime.now(ZONE_KST)
+			LocalDateTime.now()
 		));
 
 		return DepositNotifyResponse.of(

src/main/java/ditda/backend/global/apipayload/response/ApiResponse.java

@@ -31,7 +31,7 @@ public class ApiResponse<T> {
 	@JsonProperty("error")
 	private final Object error;
 
-	@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd HH:mm:ss", timezone = "Asia/Seoul")
+	@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd HH:mm:ss")
 	private final LocalDateTime timestamp;
 
 	// result가 있는 성공 응답

src/main/java/ditda/backend/global/notification/NotificationOutboxScheduler.java

@@ -1,7 +1,6 @@
 package ditda.backend.global.notification;
 
 import java.time.LocalDateTime;
-import java.time.ZoneId;
 import java.util.List;
 
 import org.springframework.data.domain.Limit;
@@ -17,14 +16,13 @@
 public class NotificationOutboxScheduler {
 
 	private static final int BATCH_SIZE = 100;
-	private static final ZoneId ZONE_KST = ZoneId.of("Asia/Seoul");
 
 	private final NotificationOutboxRepository outboxRepository;
 	private final EmailSender emailSender;
 
 	@Scheduled(cron = "0 */10 * * * *", zone = "Asia/Seoul")
 	public void dispatchPendingNotifications() {
-		LocalDateTime now = LocalDateTime.now(ZONE_KST);
+		LocalDateTime now = LocalDateTime.now();
 
 		List<NotificationOutbox> pendingAlerts = outboxRepository.findPendingScheduled(
 			OutboxStatus.PENDING,