[3주차] 정대교/[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.mysql:mysql-connector-j'
+    implementation 'org.springframework.boot:spring-boot-starter-validation'
 }
 
 tasks.named('test') {

src/main/java/com/example/springbootassignment/controller/PostController.java

@@ -0,0 +1,77 @@
+package com.example.springbootassignment.controller;
+
+import com.example.springbootassignment.dto.PostCreateRequest;
+import com.example.springbootassignment.dto.PostListResponse;
+import com.example.springbootassignment.dto.PostResponse;
+import com.example.springbootassignment.dto.PostUpdateRequest;
+import com.example.springbootassignment.service.PostService;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+
+@RestController
+@RequestMapping("/posts")
+public class PostController {
+
+    private final PostService postService;
+
+    public PostController(PostService postService) {
+        this.postService = postService;
+    }
+
+    /**
+     * 게시글 목록 조회
+     * GET /posts?page=1&size=10&sort=createdAt&order=desc
+     */
+    @GetMapping
+    public ResponseEntity<PostListResponse> getPostList(
+            @RequestParam(defaultValue = "1") int page,
+            @RequestParam(defaultValue = "10") int size,
+            @RequestParam(defaultValue = "createdAt") String sort,
+            @RequestParam(defaultValue = "desc") String order) {
+        PostListResponse response = postService.getPostList(page, size, sort, order);
+        return ResponseEntity.ok(response);
+    }
+
+    /**
+     * 게시글 상세 조회
+     * GET /posts/{postId}
+     */
+    @GetMapping("/{postId}")
+    public ResponseEntity<PostResponse> getPostDetail(@PathVariable Long postId) {
+        PostResponse response = postService.getPostDetail(postId);
+        return ResponseEntity.ok(response);
+    }
+
+    /**
+     * 게시글 작성
+     * POST /posts
+     */
+    @PostMapping
+    public ResponseEntity<PostResponse> createPost(@RequestBody PostCreateRequest request) {
+        PostResponse response = postService.createPost(request);
+        return ResponseEntity.status(HttpStatus.CREATED).body(response);
+    }
+
+    /**
+     * 게시글 수정
+     * PUT /posts/{postId}
+     */
+    @PutMapping("/{postId}")
+    public ResponseEntity<PostResponse> updatePost(
+            @PathVariable Long postId,
+            @RequestBody PostUpdateRequest request) {
+        PostResponse response = postService.updatePost(postId, request);
+        return ResponseEntity.ok(response);
+    }
+
+    /**
+     * 게시글 삭제
+     * DELETE /posts/{postId}
+     */
+    @DeleteMapping("/{postId}")
+    public ResponseEntity<Void> deletePost(@PathVariable Long postId) {
+        postService.deletePost(postId);
+        return ResponseEntity.noContent().build();
+    }
+}

src/main/java/com/example/springbootassignment/domain/post/entity/Post.java

@@ -13,15 +13,16 @@
 @Entity
 @Table(name = "posts")
 @Getter
-@NoArgsConstructor(access = AccessLevel.PROTECTED)
+@Setter
+@NoArgsConstructor
 public class Post {
 
     @Id
     @GeneratedValue(strategy = GenerationType.IDENTITY)
     private Long id;
 
     @ManyToOne(fetch = FetchType.LAZY)
-    @JoinColumn(name = "user_id", nullable = false)
+    @JoinColumn(name = "user_id", nullable = true)  // ← nullable = true로 변경
     private User user;
 
     @Column(nullable = false, length = 100)
@@ -52,4 +53,11 @@ public class Post {
 
     @OneToMany(mappedBy = "post", cascade = CascadeType.ALL)
     private List<Comment> comments = new ArrayList<>();
+
+    /**
+     * 조회수 증가
+     */
+    public void increaseViewCount() {
+        this.viewCount++;
+    }
 }

src/main/java/com/example/springbootassignment/domain/post/entity/PostRepository.java

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

src/main/java/com/example/springbootassignment/dto/ErrorResponse.java

@@ -0,0 +1,16 @@
+package com.example.springbootassignment.dto;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+
+@Getter
+@Setter
+@NoArgsConstructor
+@AllArgsConstructor
+public class ErrorResponse {
+    private String code;           // 에러 코드 (COMMON400, POST4041 등)
+    private String message;        // 사용자 친화적인 메시지
+    private String details;        // 상세 정보
+}

src/main/java/com/example/springbootassignment/dto/PostCreateRequest.java

@@ -0,0 +1,18 @@
+package com.example.springbootassignment.dto;
+
+import jakarta.validation.constraints.NotBlank;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@NoArgsConstructor
+public class PostCreateRequest {
+
+    @NotBlank(message = "제목은 필수 입력 사항입니다.")
+    private String title;
+
+    @NotBlank(message = "내용은 필수 입력 사항입니다.")
+    private String content;
+
+    private Long userId;
+}

src/main/java/com/example/springbootassignment/dto/PostListResponse.java

@@ -0,0 +1,42 @@
+package com.example.springbootassignment.dto;
+
+import com.example.springbootassignment.domain.post.entity.Post;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+import org.springframework.data.domain.Page;
+import java.time.LocalDateTime;
+import java.util.List;
+
+@Getter
+@Setter
+@NoArgsConstructor
+@AllArgsConstructor
+public class PostListResponse {
+
+    private List<Long> postId;
+    private List<String> title;
+    private List<String> nickname;
+    private List<LocalDateTime> createdAt;
+
+    /**
+     * Page<Post>를 PostListResponse로 변환
+     */
+    public static PostListResponse from(Page<Post> posts) {
+        PostListResponse response = new PostListResponse();
+        response.postId = posts.getContent().stream()
+                .map(Post::getId)
+                .toList();
+        response.title = posts.getContent().stream()
+                .map(Post::getTitle)
+                .toList();
+        response.nickname = posts.getContent().stream()
+                .map(post -> post.getUser() != null ? post.getUser().getNickname() : "unknown")
+                .toList();
+        response.createdAt = posts.getContent().stream()
+                .map(Post::getCreatedAt)
+                .toList();
+        return response;
+    }
+}

src/main/java/com/example/springbootassignment/dto/PostResponse.java

@@ -0,0 +1,34 @@
+package com.example.springbootassignment.dto;
+
+import com.example.springbootassignment.domain.post.entity.Post;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+import java.time.LocalDateTime;
+
+@Getter
+@Setter
+@NoArgsConstructor
+@AllArgsConstructor
+public class PostResponse {
+
+    private Long postId;
+    private String title;
+    private String content;
+    private LocalDateTime createdAt;
+    private LocalDateTime updatedAt;
+
+    /**
+     * Post Entity를 PostResponse DTO로 변환
+     */
+    public static PostResponse from(Post post) {
+        PostResponse response = new PostResponse();
+        response.postId = post.getId();
+        response.title = post.getTitle();
+        response.content = post.getContent();
+        response.createdAt = post.getCreatedAt();
+        response.updatedAt = post.getUpdatedAt();
+        return response;
+    }
+}

src/main/java/com/example/springbootassignment/dto/PostUpdateRequest.java

@@ -0,0 +1,16 @@
+package com.example.springbootassignment.dto;
+
+import jakarta.validation.constraints.NotBlank;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@NoArgsConstructor
+public class PostUpdateRequest {
+
+    @NotBlank(message = "제목은 필수 입력 사항입니다.")
+    private String title;
+
+    @NotBlank(message = "내용은 필수 입력 사항입니다.")
+    private String content;
+}

src/main/java/com/example/springbootassignment/exception/CommentNotFoundException.java

@@ -0,0 +1,7 @@
+package com.example.springbootassignment.exception;
+
+public class CommentNotFoundException extends RuntimeException {
+    public CommentNotFoundException(Long commentId) {
+        super("존재하지 않는 댓글입니다. id: " + commentId);
+    }
+}

src/main/java/com/example/springbootassignment/exception/ForbiddenException.java

@@ -0,0 +1,7 @@
+package com.example.springbootassignment.exception;
+
+public class ForbiddenException extends RuntimeException {
+    public ForbiddenException(Long postId, Long userId) {
+        super("게시글 id: " + postId + "를(을) 수정/삭제할 권한이 없습니다. (사용자 id: " + userId + ")");
+    }
+}

src/main/java/com/example/springbootassignment/exception/GlobalExceptionHandler.java

@@ -0,0 +1,97 @@
+package com.example.springbootassignment.exception;
+
+import com.example.springbootassignment.dto.ErrorResponse;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+
+@RestControllerAdvice
+public class GlobalExceptionHandler {
+
+    /**
+     * 잘못된 요청 (400 Bad Request)
+     * - 제목이나 내용이 비어있는 경우
+     * - 유효하지 않은 입력값
+     */
+    @ExceptionHandler(IllegalArgumentException.class)
+    public ResponseEntity<ErrorResponse> handleIllegalArgumentException(IllegalArgumentException e) {
+        ErrorResponse errorResponse = new ErrorResponse(
+                "COMMON400",
+                "잘못된 요청입니다. 입력값을 확인해주세요.",
+                e.getMessage()
+        );
+        return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(errorResponse);
+    }
+
+    /**
+     * 인증 오류 (401 Unauthorized)
+     * - 게시글 작성 시 필수 항목 누락
+     * - JWT 토큰 없음
+     */
+    @ExceptionHandler(UnauthorizedException.class)
+    public ResponseEntity<ErrorResponse> handleUnauthorizedException(UnauthorizedException e) {
+        ErrorResponse errorResponse = new ErrorResponse(
+                "COMMON401",
+                "인증이 필요합니다.",
+                e.getMessage()
+        );
+        return ResponseEntity.status(HttpStatus.UNAUTHORIZED).body(errorResponse);
+    }
+
+    /**
+     * 권한 오류 (403 Forbidden)
+     * - 자신이 쓴 글이 아닌데 수정/삭제 시도
+     */
+    @ExceptionHandler(ForbiddenException.class)
+    public ResponseEntity<ErrorResponse> handleForbiddenException(ForbiddenException e) {
+        ErrorResponse errorResponse = new ErrorResponse(
+                "COMMON403",
+                "접근 권한이 없습니다.",
+                e.getMessage()
+        );
+        return ResponseEntity.status(HttpStatus.FORBIDDEN).body(errorResponse);
+    }
+
+    /**
+     * 게시글 조회 실패 (404 Not Found)
+     * - 존재하지 않는 게시글 ID로 조회/수정/삭제 시도
+     */
+    @ExceptionHandler(PostNotFoundException.class)
+    public ResponseEntity<ErrorResponse> handlePostNotFoundException(PostNotFoundException e) {
+        ErrorResponse errorResponse = new ErrorResponse(
+                "POST4041",
+                "게시글을 찾을 수 없습니다.",
+                e.getMessage()
+        );
+        return ResponseEntity.status(HttpStatus.NOT_FOUND).body(errorResponse);
+    }
+
+    /**
+     * 댓글 조회 실패 (404 Not Found)
+     * - 존재하지 않는 댓글 ID
+     */
+    @ExceptionHandler(CommentNotFoundException.class)
+    public ResponseEntity<ErrorResponse> handleCommentNotFoundException(CommentNotFoundException e) {
+        ErrorResponse errorResponse = new ErrorResponse(
+                "COMMON404",
+                "댓글을 찾을 수 없습니다.",
+                e.getMessage()
+        );
+        return ResponseEntity.status(HttpStatus.NOT_FOUND).body(errorResponse);
+    }
+
+    /**
+     * 내부 서버 오류 (500 Internal Server Error)
+     * - 예상치 못한 오류
+     */
+    @ExceptionHandler(Exception.class)
+    public ResponseEntity<ErrorResponse> handleGeneralException(Exception e) {
+        ErrorResponse errorResponse = new ErrorResponse(
+                "COMMON500",
+                "서버 내부 오류가 발생했습니다. 잠시 후 다시 시도해주세요.",
+                e.getMessage()
+        );
+        return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body(errorResponse);
+    }
+}

src/main/java/com/example/springbootassignment/exception/PostNotFoundException.java

@@ -0,0 +1,8 @@
+package com.example.springbootassignment.exception;
+
+public class PostNotFoundException extends RuntimeException {
+
+    public PostNotFoundException(Long postId) {
+        super("존재하지 않는 게시글입니다. id: " + postId);
+    }
+}

src/main/java/com/example/springbootassignment/exception/UnauthorizedException.java

@@ -0,0 +1,7 @@
+package com.example.springbootassignment.exception;
+
+public class UnauthorizedException extends RuntimeException {
+    public UnauthorizedException(String message) {
+        super(message);
+    }
+}