[3주차] 이교형/[feat] 게시글 도메인 API 구현

build.gradle

@@ -32,6 +32,7 @@ dependencies {
 	testImplementation 'org.springframework.boot:spring-boot-starter-test'
 	testRuntimeOnly 'org.junit.platform:junit-platform-launcher'
     runtimeOnly 'com.h2database:h2'
+    implementation 'org.springframework.boot:spring-boot-starter-validation'
     // Swagger 의존성
     implementation 'org.springdoc:springdoc-openapi-starter-webmvc-ui:2.8.5'
 }

src/main/java/com/example/leets_project/common/exception/GeneralException.java

@@ -0,0 +1,12 @@
+package com.example.leets_project.common.exception;
+
+import com.example.leets_project.common.response.ErrorCode;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+
+@Getter
+@AllArgsConstructor
+public class GeneralException extends RuntimeException{
+
+    private ErrorCode errorCode;
+}

src/main/java/com/example/leets_project/common/exception/GlobalExceptionHandler.java

@@ -0,0 +1,62 @@
+package com.example.leets_project.common.exception;
+
+import com.example.leets_project.common.response.ErrorCode;
+import com.example.leets_project.common.response.GlobalResponse;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.context.support.DefaultMessageSourceResolvable;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.MethodArgumentNotValidException;
+import org.springframework.web.bind.MissingRequestHeaderException;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+
+import java.util.stream.Collectors;
+
+@RestControllerAdvice
+@Slf4j
+public class GlobalExceptionHandler {
+
+    // 커스텀 예외
+    @ExceptionHandler(GeneralException.class)
+    public ResponseEntity<GlobalResponse> handleGeneralException(GeneralException e) {
+        log.warn("GeneralException: [{}] {}", e.getErrorCode().getCode(), e.getErrorCode().getMessage());
+        return GlobalResponse.onFailure(e.getErrorCode());
+    }
+    // Validation 에러
+    @ExceptionHandler(MethodArgumentNotValidException.class)
+    public ResponseEntity<GlobalResponse> handleValidationExceptions(MethodArgumentNotValidException e) {
+        String errorDetail = e.getBindingResult()
+                .getFieldErrors()
+                .stream()
+                .map(error -> "[" + error.getField() + "]: " + error.getDefaultMessage())
+                .collect(Collectors.joining(", "));
+
+        log.warn("Validation Failed: {}", errorDetail);
+        return GlobalResponse.onFailure(ErrorCode.VALIDATION_FAILED, errorDetail);
+    }
+
+    // JSON 처리 에러
+    @ExceptionHandler({com.fasterxml.jackson.core.JsonParseException.class,
+            com.fasterxml.jackson.databind.JsonMappingException.class})
+    public ResponseEntity<GlobalResponse> handleJsonException(Exception e) {
+        log.error("JSON 처리 오류: {}", e.getMessage());
+
+        return GlobalResponse.onFailure(ErrorCode.VALIDATION_FAILED, "잘못된 JSON 형식입니다.");
+    }
+
+    // X-USER-ID 헤더 누락
+    @ExceptionHandler(MissingRequestHeaderException.class)
+    public ResponseEntity<GlobalResponse> handleMissingHeader(MissingRequestHeaderException e) {
+        log.warn("필수 헤더 누락 - {}", e.getHeaderName());
+
+        return GlobalResponse.onFailure(ErrorCode.UNAUTHORIZED, "필수 헤더가 누락되었습니다.");
+    }
+
+    // 모든 예외
+    @ExceptionHandler(Exception.class)
+    public ResponseEntity<GlobalResponse> handleGenericException(Exception e) {
+        log.error("Unexpected Error", e);
+
+        return GlobalResponse.onFailure(ErrorCode.INTERNAL_ERROR);
+    }
+}

src/main/java/com/example/leets_project/common/response/ErrorCode.java

@@ -0,0 +1,34 @@
+package com.example.leets_project.common.response;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import org.springframework.http.HttpStatus;
+
+@Getter
+@AllArgsConstructor
+public enum ErrorCode {
+
+    // COMMON
+    VALIDATION_FAILED(HttpStatus.BAD_REQUEST, "COMMON_4000", "유효하지 않은 값입니다."),
+    INVALID_INPUT(HttpStatus.BAD_REQUEST, "COMMON_4001", "잘못된 입력입니다."),
+    METHOD_NOT_ALLOWED(HttpStatus.METHOD_NOT_ALLOWED, "COMMON_4002", "허용되지 않은 요청입니다."),
+    INTERNAL_ERROR(HttpStatus.INTERNAL_SERVER_ERROR, "COMMON_5000", "서버 오류입니다."),
+
+    // AUTH
+    UNAUTHORIZED(HttpStatus.UNAUTHORIZED, "AUTH_4000", "인증이 필요합니다."),
+    FORBIDDEN(HttpStatus.FORBIDDEN, "AUTH_4001", "접근 권한이 없습니다."),
+
+    // USER
+    USER_NOT_FOUND(HttpStatus.NOT_FOUND, "USER_4040", "사용자를 찾을 수 없습니다."),
+    USER_EMAIL_ALREADY_EXISTS(HttpStatus.CONFLICT, "USER_4001", "이미 사용 중인 이메일입니다."),
+    USER_NICKNAME_ALREADY_EXISTS(HttpStatus.CONFLICT, "USER_4002", "이미 사용 중인 닉네임입니다."),
+    // POST
+    POST_NOT_FOUND(HttpStatus.NOT_FOUND, "POST_4040", "게시글을 찾을 수 없습니다."),
+    POST_INVALID(HttpStatus.BAD_REQUEST, "POST_4001", "게시글 입력값이 올바르지 않습니다."),
+    POST_FORBIDDEN(HttpStatus.FORBIDDEN, "POST_4003", "작성자만 수정/삭제할 수 있습니다.");
+
+    private final HttpStatus status;
+    private final String code;
+    private final String message;
+
+}

src/main/java/com/example/leets_project/common/response/GlobalResponse.java

@@ -0,0 +1,46 @@
+package com.example.leets_project.common.response;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+import org.springframework.http.ResponseEntity;
+
+@Getter
+@RequiredArgsConstructor
+@JsonPropertyOrder({"isSuccess", "code", "message", "result"})
+public class GlobalResponse {
+
+    private final Boolean isSuccess; // 성공, 실패 여부
+
+    private final String code; // 상태 코드
+
+    private final String message; // 구체적인 메시지
+
+    @JsonInclude(JsonInclude.Include.NON_NULL)
+    private final Object result; //반환할 객체
+
+    public static ResponseEntity<GlobalResponse> onSuccess(SuccessCode successCode, Object result){
+        return new ResponseEntity<>(
+                new GlobalResponse(true, successCode.getCode(), successCode.getMessage(), result),
+                successCode.getStatus());
+    }
+
+    public static ResponseEntity<GlobalResponse> onSuccess(SuccessCode successCode){
+        return new ResponseEntity<>(
+                new GlobalResponse(true, successCode.getCode(), successCode.getMessage(), null),
+                successCode.getStatus());
+    }
+
+    public static ResponseEntity<GlobalResponse> onFailure(ErrorCode errorCode, Object result){
+        return new ResponseEntity<>(
+                new GlobalResponse(false, errorCode.getCode(), errorCode.getMessage(), result),
+                errorCode.getStatus());
+    }
+
+    public static ResponseEntity<GlobalResponse> onFailure(ErrorCode errorCode){
+        return new ResponseEntity<>(
+                new GlobalResponse(false, errorCode.getCode(), errorCode.getMessage(), null),
+                errorCode.getStatus());
+    }
+}

src/main/java/com/example/leets_project/common/response/SuccessCode.java

@@ -0,0 +1,23 @@
+package com.example.leets_project.common.response;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import org.springframework.http.HttpStatus;
+
+@Getter
+@AllArgsConstructor
+public enum SuccessCode {
+
+    // USER
+    USER_CREATE(HttpStatus.CREATED, "USER_2010", "유저 생성 성공"),
+    // POST
+    POST_LIST(HttpStatus.OK, "POST_2000", "게시글 목록 조회 성공"),
+    POST_DETAIL(HttpStatus.OK, "POST_2001", "게시글 조회 성공"),
+    POST_UPDATE(HttpStatus.OK, "POST_2002", "게시글 수정 성공"),
+    POST_DELETE(HttpStatus.OK, "POST_2003", "게시글 삭제 성공"),
+    POST_CREATE(HttpStatus.CREATED, "POST_2010", "게시글 생성 성공");
+
+    private final HttpStatus status;
+    private final String code;
+    private final String message;
+}

src/main/java/com/example/leets_project/domain/comment/Comment.java

@@ -1,17 +1,13 @@
 package com.example.leets_project.domain.comment;
 
 import com.example.leets_project.common.entity.BaseEntity;
-import com.example.leets_project.domain.post.Post;
+import com.example.leets_project.domain.post.entity.Post;
 import com.example.leets_project.domain.user.User;
 import jakarta.persistence.*;
 import lombok.AccessLevel;
 import lombok.Builder;
 import lombok.Getter;
 import lombok.NoArgsConstructor;
-import org.hibernate.annotations.CreationTimestamp;
-import org.hibernate.annotations.UpdateTimestamp;
-
-import java.time.LocalDateTime;
 
 @Entity
 @Table(name = "comments")

src/main/java/com/example/leets_project/domain/post/Post.java → src/main/java/com/example/leets_project/domain/post/entity/Post.java

@@ -1,17 +1,16 @@
-package com.example.leets_project.domain.post;
+package com.example.leets_project.domain.post.entity;
 
 import com.example.leets_project.common.entity.BaseEntity;
+import com.example.leets_project.common.exception.GeneralException;
+import com.example.leets_project.common.response.ErrorCode;
 import com.example.leets_project.domain.comment.Comment;
 import com.example.leets_project.domain.user.User;
 import jakarta.persistence.*;
 import lombok.AccessLevel;
 import lombok.Builder;
 import lombok.Getter;
 import lombok.NoArgsConstructor;
-import org.hibernate.annotations.CreationTimestamp;
-import org.hibernate.annotations.UpdateTimestamp;
 
-import java.time.LocalDateTime;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -49,4 +48,16 @@ public Post(User user, String title, String content, String description) {
         this.content = content;
         this.description = description;
     }
+    public void updatePost(String title, String content, String description, Long requesterId) {
+        validateOwner(requesterId);
+        this.title = title;
+        this.content = content;
+        this.description = description;
+    }
+
+    public void validateOwner(Long userId) {
+        if (!this.user.getId().equals(userId)) {
+            throw new GeneralException(ErrorCode.POST_FORBIDDEN);
+        }
+    }
 }

src/main/java/com/example/leets_project/domain/post/repository/PostRepository.java

@@ -0,0 +1,7 @@
+package com.example.leets_project.domain.post.repository;
+
+import com.example.leets_project.domain.post.entity.Post;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface PostRepository extends JpaRepository<Post, Long> {
+}

src/main/java/com/example/leets_project/domain/post/service/PostService.java

@@ -0,0 +1,111 @@
+package com.example.leets_project.domain.post.service;
+
+import com.example.leets_project.common.exception.GeneralException;
+import com.example.leets_project.common.response.ErrorCode;
+import com.example.leets_project.domain.post.entity.Post;
+import com.example.leets_project.domain.post.repository.PostRepository;
+import com.example.leets_project.domain.post.web.dto.*;
+import com.example.leets_project.domain.user.User;
+import com.example.leets_project.domain.user.repository.UserRepository;
+import lombok.RequiredArgsConstructor;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.PageRequest;
+import org.springframework.data.domain.Sort;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+@Service
+@RequiredArgsConstructor
+@Transactional(readOnly = true)
+public class PostService {
+
+    private final PostRepository postRepository;
+    private final UserRepository userRepository;
+
+    private static final int MIN_PAGE = 0;
+    private static final int MAX_PAGE = 10;
+
+    // 1. 게시글 생성
+    @Transactional
+    public PostCreateResponse createPost(Long currentUserId, PostCreateRequest request) {
+        // 사용자 존재 확인
+        User user = findUserOrThrow(currentUserId);
+
+        Post post = Post.builder()
+                .user(user)
+                .title(request.getTitle())
+                .content(request.getContent())
+                .description(request.getDescription())
+                .build();
+
+        Post savedPost = postRepository.save(post);
+
+        return PostCreateResponse.from(savedPost);
+    }
+
+    // 2. 게시글 목록 조회 (페이징)
+    public Page<PostListResponse> getPosts(int page, int size) {
+
+        validatePageRange(page);
+        PageRequest pageable = PageRequest.of(page, size, Sort.by(Sort.Direction.DESC, "createdAt"));
+
+        return postRepository.findAll(pageable)
+                .map(PostListResponse::from);
+    }
+
+    // 3. 게시글 상세 조회
+    public PostDetailResponse getPostDetail(Long postId) {
+
+        Post post = findPostOrThrow(postId);
+
+        return PostDetailResponse.from(post);
+    }
+
+    // 4. 게시글 수정
+    @Transactional
+    public PostUpdateResponse updatePost(Long postId, Long currentUserId, PostUpdateRequest request) {
+
+        Post post = findPostOrThrow(postId);
+
+        post.updatePost(
+                request.getTitle(),
+                request.getContent(),
+                request.getDescription(),
+                currentUserId
+        );
+
+        return PostUpdateResponse.from(post);
+    }
+
+    // 5. 게시글 삭제
+    @Transactional
+    public PostDeleteResponse deletePost(Long postId, Long currentUserId) {
+
+        Post post = findPostOrThrow(postId);
+
+        post.validateOwner(currentUserId);
+
+        postRepository.delete(post);
+
+        return PostDeleteResponse.of(postId);
+    }
+
+    // 공통 검증 로직
+    // 게시글 조회
+    private Post findPostOrThrow(Long postId) {
+        return postRepository.findById(postId)
+                .orElseThrow(() -> new GeneralException(ErrorCode.POST_NOT_FOUND));
+    }
+
+    // 사용자 조회
+    private User findUserOrThrow(Long userId) {
+        return userRepository.findById(userId)
+                .orElseThrow(() -> new GeneralException(ErrorCode.USER_NOT_FOUND));
+    }
+
+    private void validatePageRange(int page) {
+        if (page < MIN_PAGE || page > MAX_PAGE) {
+            throw new GeneralException(ErrorCode.POST_INVALID);
+        }
+    }
+}