feat: 사용자 회원가입 API 구현

src/main/java/site/sopkathon/product/common/message/SuccessMessage.java

@@ -7,6 +7,7 @@
 @AllArgsConstructor
 public enum SuccessMessage {
     HEALTH_CHECK_SUCCESS("Health check success"),
+    MEMBER_SIGN_UP_SUCCESS("Member sign up success"),
     TEST_IMAGE_UPLOAD_SUCCESS("Test image upload success");
 
     private final String message;

src/main/java/site/sopkathon/product/controller/MemberController.java

@@ -0,0 +1,43 @@
+package site.sopkathon.product.controller;
+
+
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.responses.ApiResponse;
+import io.swagger.v3.oas.annotations.responses.ApiResponses;
+import io.swagger.v3.oas.annotations.tags.Tag;
+import lombok.RequiredArgsConstructor;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+import site.sopkathon.product.common.message.SuccessMessage;
+import site.sopkathon.product.common.response.BaseResponse;
+import site.sopkathon.product.dto.request.member.MemberSignUpRequest;
+import site.sopkathon.product.dto.response.member.MemberSignUpResponse;
+import site.sopkathon.product.service.MemberService;
+
+@RestController
+@RequestMapping("/members")
+@RequiredArgsConstructor
+@Tag(name = "[Member API]", description = "회원 관련")
+public class MemberController {
+
+    private final MemberService memberService;
+
+
+    @Operation(summary = "회원 가입", description = "회원 가입을 진행합니다.")
+    @ApiResponses(
+            value = {
+                    @ApiResponse(responseCode = "201", description = "회원 가입 성공")
+            }
+    )
+    @PostMapping("/sign-up")
+    public ResponseEntity<BaseResponse<MemberSignUpResponse>> signUp(
+            @RequestBody final MemberSignUpRequest request
+            ) {
+        final MemberSignUpResponse response = memberService.signUp(request);
+        return BaseResponse.created(SuccessMessage.MEMBER_SIGN_UP_SUCCESS, response);
+    }
+
+}

src/main/java/site/sopkathon/product/domain/Member.java

@@ -1,15 +1,24 @@
 package site.sopkathon.product.domain;
 
-import jakarta.persistence.Entity;
-import jakarta.persistence.GeneratedValue;
-import jakarta.persistence.GenerationType;
-import jakarta.persistence.Id;
+import jakarta.persistence.*;
 import lombok.AccessLevel;
+import lombok.Builder;
+import lombok.Getter;
 import lombok.NoArgsConstructor;
+import site.sopkathon.product.common.entity.BaseTimeEntity;
 
 @Entity
 @NoArgsConstructor(access = AccessLevel.PROTECTED)
-public class Member {
+@Getter
+public class Member extends BaseTimeEntity {
     @Id @GeneratedValue(strategy = GenerationType.IDENTITY)
     private Long id;
+
+    @Column(nullable = false, unique = true, length = 50)
+    private String username;
+
+    @Builder
+    public Member(String username) {
+        this.username = username;
+    }
 }

src/main/java/site/sopkathon/product/dto/request/member/MemberSignUpRequest.java

@@ -0,0 +1,6 @@
+package site.sopkathon.product.dto.request.member;
+
+public record MemberSignUpRequest(
+        String username
+) {
+}

src/main/java/site/sopkathon/product/dto/response/member/MemberSignUpResponse.java

@@ -0,0 +1,10 @@
+package site.sopkathon.product.dto.response.member;
+
+public record MemberSignUpResponse(
+        long userId
+) {
+
+    public static MemberSignUpResponse of(long userId) {
+        return new MemberSignUpResponse(userId);
+    }
+}

src/main/java/site/sopkathon/product/repository/MemberRepository.java

@@ -4,4 +4,6 @@
 import site.sopkathon.product.domain.Member;
 
 public interface MemberRepository extends JpaRepository<Member, Long> {
+
+    boolean existsByUsername(String username);
 }

src/main/java/site/sopkathon/product/service/MemberService.java

@@ -0,0 +1,33 @@
+package site.sopkathon.product.service;
+
+
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+import site.sopkathon.product.common.exception.BadRequestException;
+import site.sopkathon.product.domain.Member;
+import site.sopkathon.product.dto.request.member.MemberSignUpRequest;
+import site.sopkathon.product.dto.response.member.MemberSignUpResponse;
+import site.sopkathon.product.repository.MemberRepository;
+
+@Service
+@RequiredArgsConstructor
+@Transactional(readOnly = true)
+public class MemberService {
+
+    private final MemberRepository memberRepository;
+
+    @Transactional
+    public MemberSignUpResponse signUp(final MemberSignUpRequest request) {
+        if (!memberRepository.existsByUsername(request.username())) {
+            throw new BadRequestException("이미 존재하는 회원입니다.");
+        }
+        final Member savedMember = memberRepository.save(
+                Member.builder()
+                        .username(request.username())
+                        .build()
+        );
+        return MemberSignUpResponse.of(savedMember.getId());
+    }
+
+}