refactor: Siteuser 도메인 리팩터링

src/main/java/com/example/solidconnection/common/exception/ErrorCode.java

@@ -96,6 +96,9 @@ public enum ErrorCode {
     USER_DO_NOT_HAVE_GPA(HttpStatus.BAD_REQUEST.value(), "해당 유저의 학점을 찾을 수 없음"),
     REJECTED_REASON_REQUIRED(HttpStatus.BAD_REQUEST.value(), "거절 사유가 필요합니다."),
 
+    // database
+    DATA_INTEGRITY_VIOLATION(HttpStatus.CONFLICT.value(), "데이터베이스 무결성 제약조건 위반이 발생했습니다."),
+
     // general
     JSON_PARSING_FAILED(HttpStatus.BAD_REQUEST.value(), "JSON 파싱을 할 수 없습니다."),
     JWT_EXCEPTION(HttpStatus.BAD_REQUEST.value(), "JWT 토큰을 처리할 수 없습니다."),

src/main/java/com/example/solidconnection/siteuser/controller/MyPageController.java

@@ -1,10 +1,13 @@
 package com.example.solidconnection.siteuser.controller;
 
+import com.example.solidconnection.common.exception.CustomException;
+import com.example.solidconnection.common.exception.ErrorCode;
 import com.example.solidconnection.common.resolver.AuthorizedUser;
 import com.example.solidconnection.siteuser.domain.SiteUser;
 import com.example.solidconnection.siteuser.dto.MyPageResponse;
 import com.example.solidconnection.siteuser.service.MyPageService;
 import lombok.RequiredArgsConstructor;
+import org.springframework.dao.DataIntegrityViolationException;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PatchMapping;
@@ -13,6 +16,8 @@
 import org.springframework.web.bind.annotation.RestController;
 import org.springframework.web.multipart.MultipartFile;
 
+import static com.example.solidconnection.common.exception.ErrorCode.DATA_INTEGRITY_VIOLATION;
+
 @RequiredArgsConstructor
 @RequestMapping("/my")
 @RestController
@@ -34,7 +39,21 @@ public ResponseEntity<Void> updateMyPageInfo(
             @RequestParam(value = "file", required = false) MultipartFile imageFile,
             @RequestParam(value = "nickname", required = false) String nickname
     ) {
-        myPageService.updateMyPageInfo(siteUser, imageFile, nickname);
-        return ResponseEntity.ok().build();
+        try {
+            myPageService.updateMyPageInfo(siteUser, imageFile, nickname);
+            return ResponseEntity.ok().build();
+        } catch (DataIntegrityViolationException e) {
+            throw new CustomException(determineErrorCode(e));
+        }
+    }
+
+    private ErrorCode determineErrorCode(DataIntegrityViolationException e) {
+        String message = e.getMostSpecificCause().getMessage().toLowerCase();
+
+        if (message.contains("unique") && message.contains("nickname")) {
+            return ErrorCode.NICKNAME_ALREADY_EXISTED;
+        }
+
+        return ErrorCode.DATA_INTEGRITY_VIOLATION;
     }
 }

src/main/java/com/example/solidconnection/siteuser/service/MyPageService.java

@@ -20,7 +20,6 @@
 import java.util.List;
 
 import static com.example.solidconnection.common.exception.ErrorCode.CAN_NOT_CHANGE_NICKNAME_YET;
-import static com.example.solidconnection.common.exception.ErrorCode.NICKNAME_ALREADY_EXISTED;
 
 @RequiredArgsConstructor
 @Service
@@ -48,7 +47,6 @@ public MyPageResponse getMyPageInfo(SiteUser siteUser) {
     @Transactional
     public void updateMyPageInfo(SiteUser siteUser, MultipartFile imageFile, String nickname) {
         if (nickname != null) {
-            validateNicknameUnique(nickname);
             validateNicknameNotChangedRecently(siteUser.getNicknameModifiedAt());
             siteUser.setNickname(nickname);
             siteUser.setNicknameModifiedAt(LocalDateTime.now());
@@ -65,12 +63,6 @@ public void updateMyPageInfo(SiteUser siteUser, MultipartFile imageFile, String
         siteUserRepository.save(siteUser);
     }
 
-    private void validateNicknameUnique(String nickname) {
-        if (siteUserRepository.existsByNickname(nickname)) {
-            throw new CustomException(NICKNAME_ALREADY_EXISTED);
-        }
-    }
-
     private void validateNicknameNotChangedRecently(LocalDateTime lastModifiedAt) {
         if (lastModifiedAt == null) {
             return;