feat: nickname duplication check API

src/main/java/com/fullcar/core/response/ErrorCode.java

@@ -16,6 +16,7 @@ public enum ErrorCode {
     EMAIL_ADDRESS_IN_BLACKLIST(BAD_REQUEST, "블랙리스트에 있는 이메일 주소입니다."),
     CANNOT_SEND_TO_OWN_CARPOOL(BAD_REQUEST, "자기자신의 카풀에는 신청할 수 없습니다."),
     DUPLICATED_FORM(BAD_REQUEST, "이미 요청을 보낸 카풀입니다."),
+    DUPLICATED_NICKNAME(BAD_REQUEST, "중복된 닉네임 입니다."),
 
     /* 401 UNAUTHORIZED */
     UNAUTHORIZED_KAKAO_TOKEN(UNAUTHORIZED, "유효하지 않은 카카오 토큰"),

src/main/java/com/fullcar/core/response/SuccessCode.java

@@ -15,7 +15,8 @@ public enum SuccessCode {
     SIGNIN_SUCCESS(OK, "소셜로그인 성공"),
     GET_NEW_TOKEN_SUCCESS(OK, "토큰 재발급 성공"),
     READ_SUCCESS(OK, "조회 성공"),
-    EMAIL_SENT_SUCCESS(OK, "인증메일 발송 성공");
+    EMAIL_SENT_SUCCESS(OK, "인증메일 발송 성공"),
+    AVAILABLE_NICKNAME(OK, "사용 가능한 닉네임");
 
     private final HttpStatus status;
     private final String message;

src/main/java/com/fullcar/member/application/member/MemberService.java

@@ -1,10 +1,13 @@
 package com.fullcar.member.application.member;
 
+import com.fullcar.core.exception.CustomException;
 import com.fullcar.core.exception.NotFoundException;
 import com.fullcar.core.response.ErrorCode;
 import com.fullcar.member.domain.member.*;
+import com.fullcar.member.presentation.member.dto.request.NicknameRequestDto;
 import com.fullcar.member.presentation.member.dto.request.OnboardingRequestDto;
 import com.fullcar.member.presentation.member.dto.response.MemberGetResponseDto;
+import com.fullcar.member.presentation.member.dto.response.NicknameResponseDto;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
@@ -38,4 +41,15 @@ public void registerOnboarding(Member member, OnboardingRequestDto onboardingReq
     public MemberGetResponseDto getMember(Member member) {
         return memberMapper.toDto(member);
     }
+
+    @Transactional(readOnly = true)
+    public NicknameResponseDto checkNicknameDuplication(NicknameRequestDto nicknameRequestDto) {
+        if (memberRepository.existsByNickname(nicknameRequestDto.getNickname()))
+            throw new CustomException(ErrorCode.DUPLICATED_NICKNAME);
+        else  {
+            return NicknameResponseDto.builder()
+                    .nickname(nicknameRequestDto.getNickname())
+                    .build();
+        }
+    }
 }

src/main/java/com/fullcar/member/domain/member/MemberRepository.java

@@ -22,6 +22,8 @@ public interface MemberRepository extends JpaRepository<Member, MemberId> {
 
     Optional<Member> findByRefreshToken(String refreshToken);
 
+    boolean existsByNickname(String nickname);
+
     default Member findByIdAndIsDeletedOrThrow(MemberId id, boolean isDeleted) {
         return findByIdAndIsDeleted(id, isDeleted)
                 .orElseThrow(() -> new CustomException(ErrorCode.NOT_EXIST_USER));

src/main/java/com/fullcar/member/presentation/member/MemberController.java

@@ -6,9 +6,11 @@
 import com.fullcar.member.application.member.MemberService;
 import com.fullcar.member.domain.member.Member;
 import com.fullcar.member.domain.member.service.MailService;
+import com.fullcar.member.presentation.member.dto.request.NicknameRequestDto;
 import com.fullcar.member.presentation.member.dto.request.OnboardingRequestDto;
 import com.fullcar.member.presentation.member.dto.request.EmailRequestDto;
 import com.fullcar.member.presentation.member.dto.response.MemberGetResponseDto;
+import com.fullcar.member.presentation.member.dto.response.NicknameResponseDto;
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.media.Content;
 import io.swagger.v3.oas.annotations.responses.ApiResponses;
@@ -58,4 +60,15 @@ public ApiResponse<Object> sendAuthenticationMail(@RequestBody EmailRequestDto e
         mailService.sendMail(emailRequestDto);
         return ApiResponse.success(SuccessCode.EMAIL_SENT_SUCCESS);
     }
+
+    @Operation(summary = "닉네임 중복 검사 API")
+    @ApiResponses({
+            @io.swagger.v3.oas.annotations.responses.ApiResponse(responseCode = "200", description = "사용 가능한 닉네임"),
+            @io.swagger.v3.oas.annotations.responses.ApiResponse(responseCode = "500", description = "서버 내부 오류", content = @Content)
+    })
+    @PostMapping("/onboarding/nickname")
+    public ApiResponse<NicknameResponseDto> checkNicknameDuplication(@RequestBody NicknameRequestDto nicknameRequestDto) {
+        NicknameResponseDto responseDto = memberService.checkNicknameDuplication(nicknameRequestDto);
+        return ApiResponse.success(SuccessCode.AVAILABLE_NICKNAME, responseDto);
+    }
 }

src/main/java/com/fullcar/member/presentation/member/dto/request/NicknameRequestDto.java

@@ -0,0 +1,15 @@
+package com.fullcar.member.presentation.member.dto.request;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+import lombok.AccessLevel;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@AllArgsConstructor(access = AccessLevel.PROTECTED)
+@NoArgsConstructor(access = AccessLevel.PROTECTED)
+public class NicknameRequestDto {
+    @Schema(description = "닉네임", example = "오예")
+    private String nickname;
+}

src/main/java/com/fullcar/member/presentation/member/dto/response/NicknameResponseDto.java

@@ -0,0 +1,14 @@
+package com.fullcar.member.presentation.member.dto.response;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+import lombok.*;
+
+@Getter
+@Builder
+@AllArgsConstructor(access = AccessLevel.PROTECTED)
+@NoArgsConstructor(access = AccessLevel.PROTECTED)
+@Schema(description = "닉네임 응답 모델")
+public class NicknameResponseDto {
+    @Schema(description = "닉네임", example = "오예")
+    private String nickname;
+}