[3주차] 최유찬/[feat] 게시글 도메인 API 구현

build.gradle

@@ -32,12 +32,14 @@ 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'
 }
 
 tasks.named('test') {
 	useJUnitPlatform()
 }
 
 springBoot {
-	mainClass = 'com.example.demo.DemoApplication'
+	mainClass = 'com.example.demo1.Demo1Application'
 }
+

src/main/java/com/example/demo1/Demo1Application.java

@@ -2,10 +2,14 @@
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.boot.autoconfigure.domain.EntityScan;
 import org.springframework.data.jpa.repository.config.EnableJpaAuditing;
+import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
 
-@EnableJpaAuditing // 생성일/수정일 자동 생성을 위해 꼭 필요해요!
-@SpringBootApplication // (exclude = ...) 부분을 지워서 DB 자동 설정을 활성화합니다.
+@EnableJpaAuditing // 생성일/수정일 자동 기록을 위해 꼭 필요합니다!
+@SpringBootApplication
+@EnableJpaRepositories(basePackages = "com.example.demo1")
+@EntityScan(basePackages = "com.example.demo1")
 public class Demo1Application {
     public static void main(String[] args) {
         SpringApplication.run(Demo1Application.class, args);

src/main/java/com/example/demo1/domain/global/exception/GlobalExceptionHandler.java

@@ -0,0 +1,34 @@
+package com.example.demo1.domain.global.exception;
+
+import com.example.demo1.domain.global.response.BaseResponse;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.MethodArgumentNotValidException;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.NoSuchElementException;
+
+@RestControllerAdvice
+public class GlobalExceptionHandler {
+
+    // 1. 유효성 검사 실패 처리 (제목/내용 빈 값 등 - 코드 4002) [cite: 449, 479]
+    @ExceptionHandler(MethodArgumentNotValidException.class)
+    public ResponseEntity<BaseResponse<Map<String, String>>> handleValidationException(MethodArgumentNotValidException e) {
+        Map<String, String> errors = new HashMap<>();
+        e.getBindingResult().getFieldErrors().forEach(error ->
+                errors.put(error.getField(), error.getDefaultMessage()));
+
+        return ResponseEntity.status(HttpStatus.BAD_REQUEST)
+                .body(BaseResponse.onFailure("4002", "잘못된 요청입니다.", errors));
+    }
+
+    // 2. 리소스를 찾을 수 없을 때 처리 (게시글 없음 - 코드 4040) [cite: 436, 480]
+    @ExceptionHandler(NoSuchElementException.class)
+    public ResponseEntity<BaseResponse<Map<String, Long>>> handleNotFoundException(NoSuchElementException e) {
+        return ResponseEntity.status(HttpStatus.NOT_FOUND)
+                .body(BaseResponse.onFailure("4040", e.getMessage(), null));
+    }
+}

src/main/java/com/example/demo1/domain/global/response/BaseResponse.java

@@ -0,0 +1,26 @@
+package com.example.demo1.domain.global.response;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+
+@Getter
+@AllArgsConstructor
+public class BaseResponse<T> {
+    private final Boolean isSuccess;
+    private final String code;
+    private final String message;
+
+    @JsonInclude(JsonInclude.Include.NON_NULL) // 결과값이 null이면 JSON에 포함하지 않음
+    private T result;
+
+    // 성공 응답 정적 팩토리 메서드
+    public static <T> BaseResponse<T> onSuccess(String code, String message, T result) {
+        return new BaseResponse<>(true, code, message, result);
+    }
+
+    // 실패 응답 정적 팩토리 메서드
+    public static <T> BaseResponse<T> onFailure(String code, String message, T result) {
+        return new BaseResponse<>(false, code, message, result);
+    }
+}

src/main/java/com/example/demo1/domain/post/controller/PostController.java

@@ -0,0 +1,50 @@
+package com.example.demo1.domain.post.controller;
+
+import com.example.demo1.domain.global.response.BaseResponse;
+import com.example.demo1.domain.post.dto.PostRequestDto;
+import com.example.demo1.domain.post.dto.PostResponseDto;
+import com.example.demo1.domain.post.service.PostService;
+import jakarta.validation.Valid;
+import lombok.RequiredArgsConstructor;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.List;
+
+@RestController
+@RequestMapping("/posts")
+@RequiredArgsConstructor
+public class PostController {
+
+    private final PostService postService;
+
+    // [API 1] 목록 조회
+    @GetMapping
+    public BaseResponse<List<PostResponseDto>> getPosts() {
+        return BaseResponse.onSuccess("2000", "게시글 목록 조회 성공", postService.findAll());
+    }
+
+    // [API 2] 상세 조회 (findById 대신 getPostDetail로 수정)
+    @GetMapping("/{postId}")
+    public BaseResponse<PostResponseDto> getPost(@PathVariable Long postId) {
+        return BaseResponse.onSuccess("2001", "게시글 조회 성공", postService.getPostDetail(postId));
+    }
+
+    // [API 3] 작성
+    @PostMapping
+    public BaseResponse<PostResponseDto> createPost(@Valid @RequestBody PostRequestDto requestDto) {
+        return BaseResponse.onSuccess("2010", "게시글 생성 성공", postService.save(requestDto));
+    }
+
+    // [API 4] 수정
+    @PutMapping("/{postId}")
+    public BaseResponse<PostResponseDto> updatePost(@PathVariable Long postId, @Valid @RequestBody PostRequestDto requestDto) {
+        return BaseResponse.onSuccess("2002", "게시글 수정 성공", postService.update(postId, requestDto));
+    }
+
+    // [API 5] 삭제
+    @DeleteMapping("/{postId}")
+    public BaseResponse<String> deletePost(@PathVariable Long postId) {
+        postService.delete(postId);
+        return BaseResponse.onSuccess("2003", "게시글 삭제 성공", "삭제된 게시글 ID: " + postId);
+    }
+}

src/main/java/com/example/demo1/domain/post/dto/PostBlockDto.java

@@ -0,0 +1,16 @@
+package com.example.demo1.domain.post.dto;
+
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@Builder
+@NoArgsConstructor
+@AllArgsConstructor
+public class PostBlockDto {
+    private String blockType;
+    private String textContent;
+    private String imageUrl;
+}

src/main/java/com/example/demo1/domain/post/dto/PostRequestDto.java

@@ -0,0 +1,25 @@
+package com.example.demo1.domain.post.dto;
+
+import jakarta.validation.constraints.NotBlank;
+import lombok.Getter;
+import lombok.Setter;
+
+import java.util.List;
+
+@Getter
+@Setter
+public class PostRequestDto {
+
+    private Long userId; // 작성 시 필요
+
+    @NotBlank(message = "제목은 비어 있을 수 없습니다.")
+    private String title;
+
+    @NotBlank(message = "내용은 비어 있을 수 없습니다.")
+    private String content;
+
+    @NotBlank(message = "설명은 비어 있을 수 없습니다.")
+    private String description;
+
+    private List<PostBlockDto> blocks;
+}

src/main/java/com/example/demo1/domain/post/dto/PostResponseDto.java

@@ -0,0 +1,24 @@
+package com.example.demo1.domain.post.dto;
+
+import com.fasterxml.jackson.annotation.JsonFormat;
+import lombok.Builder;
+import lombok.Getter;
+import java.time.LocalDateTime;
+import java.util.List;
+
+@Getter
+@Builder
+public class PostResponseDto {
+    private Long postId;
+    private String title;
+    private String content;
+    private String description;
+    private String authorNickname;
+
+    @JsonFormat(pattern = "yyyy-MM-dd'T'HH:mm:ss") // 명세서 포맷 준수
+    private LocalDateTime createdAt;
+
+    @JsonFormat(pattern = "yyyy-MM-dd'T'HH:mm:ss")
+    private LocalDateTime updatedAt;
+    private List<PostBlockDto> blocks;
+}

src/main/java/com/example/demo1/domain/post/entity/Post.java

@@ -19,10 +19,10 @@ public class Post extends BaseEntity {
 
     @Id
     @GeneratedValue(strategy = GenerationType.IDENTITY)
-    private Integer id;
+    private Long id; // [★체크] Service와 타입을 맞추기 위해 Integer 대신 Long 사용을 권장합니다.
 
     @ManyToOne(fetch = FetchType.LAZY)
-    @JoinColumn(name = "user_id", nullable = false)
+    @JoinColumn(name = "user_id", nullable = true) // [★체크] 테스트 편의를 위해 일단 nullable = true로 수정했습니다.
     private User user;
 
     @Column(length = 255)
@@ -37,4 +37,12 @@ public class Post extends BaseEntity {
     @Builder.Default
     @OneToMany(mappedBy = "post", cascade = CascadeType.ALL)
     private List<Comment> comments = new ArrayList<>();
+
+    // [★추가] 게시글 수정을 위한 핵심 메서드입니다.
+    // 이 메서드가 있어야 PostService의 50라인 에러가 사라집니다.
+    public void update(String title, String content, String description) {
+        this.title = title;
+        this.content = content;
+        this.description = description;
+    }
 }

src/main/java/com/example/demo1/domain/post/repository/PostRepository.java

@@ -0,0 +1,10 @@
+package com.example.demo1.domain.post.repository;
+
+import com.example.demo1.domain.post.entity.Post;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+@Repository // [★필수] 스프링이 이 인터페이스를 데이터 저장소로 인식하게 합니다.
+public interface PostRepository extends JpaRepository<Post, Long> {
+    // 아무 내용도 적지 않아도 기본 CRUD 기능이 작동합니다.
+}

src/main/java/com/example/demo1/domain/post/service/PostService.java

@@ -0,0 +1,109 @@
+package com.example.demo1.domain.post.service;
+
+import com.example.demo1.domain.post.dto.PostBlockDto;
+import com.example.demo1.domain.post.dto.PostRequestDto;
+import com.example.demo1.domain.post.dto.PostResponseDto;
+import com.example.demo1.domain.post.entity.Post;
+import com.example.demo1.domain.post.repository.PostRepository;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.time.LocalDateTime;
+import java.util.List;
+import java.util.NoSuchElementException;
+import java.util.stream.Collectors;
+
+@Service
+@RequiredArgsConstructor
+@Transactional(readOnly = true)
+public class PostService {
+
+    private final PostRepository postRepository;
+
+    // 1. 목록 조회 로직 (엔티티 리스트를 DTO 리스트로 변환해서 반환하는 것이 정석입니다)
+    public List<PostResponseDto> findAll() {
+        return postRepository.findAll().stream()
+                .map(post -> PostResponseDto.builder()
+                        .postId(post.getId())
+                        .title(post.getTitle())
+                        .content(post.getContent())
+                        .description(post.getDescription())
+                        .authorNickname("jae")
+                        .createdAt(post.getCreatedAt())
+                        .build())
+                .collect(Collectors.toList());
+    }
+
+    // 2. 상세 조회 로직
+    public PostResponseDto getPostDetail(Long postId) {
+        Post post = postRepository.findById(postId)
+                .orElseThrow(() -> new NoSuchElementException("해당 게시글을 찾을 수 없습니다."));
+
+        List<PostBlockDto> mockBlocks = List.of(
+                PostBlockDto.builder()
+                        .blockType("TEXT")
+                        .textContent("본문 내용입니다.")
+                        .imageUrl(null)
+                        .build()
+        );
+
+        return PostResponseDto.builder()
+                .postId(post.getId())
+                .title(post.getTitle())
+                .content(post.getContent())
+                .description(post.getDescription())
+                .authorNickname("jae")
+                .createdAt(post.getCreatedAt())
+                .build();
+    }
+
+    // 3. 작성 로직 (하나로 통합함!)
+    @Transactional
+    public PostResponseDto save(PostRequestDto dto) {
+        Post post = Post.builder()
+                .title(dto.getTitle())
+                .content(dto.getContent())
+                .description(dto.getDescription())
+                .build();
+
+        Post savedPost = postRepository.save(post);
+
+        return PostResponseDto.builder()
+                .postId(savedPost.getId())
+                .title(savedPost.getTitle())
+                .content(savedPost.getContent())
+                .description(savedPost.getDescription())
+                .authorNickname("yuchan")
+                .createdAt(savedPost.getCreatedAt() != null ? savedPost.getCreatedAt() : LocalDateTime.now())
+                .blocks(dto.getBlocks())
+                .build();
+    }
+
+    // 4. 수정 로직
+    @Transactional
+    public PostResponseDto update(Long postId, PostRequestDto dto) {
+        Post post = postRepository.findById(postId)
+                .orElseThrow(() -> new NoSuchElementException("해당 게시글을 찾을 수 없습니다."));
+
+        post.update(dto.getTitle(), dto.getContent(), dto.getDescription());
+
+        return PostResponseDto.builder()
+                .postId(post.getId())
+                .title(post.getTitle())
+                .content(post.getContent())
+                .description(post.getDescription())
+                .authorNickname("jae")
+                .createdAt(post.getCreatedAt())
+                .build();
+    }
+
+    // 5. 삭제 로직
+    @Transactional
+    public void delete(Long postId) {
+        if (!postRepository.existsById(postId)) {
+            throw new NoSuchElementException("해당 게시글을 찾을 수 없습니다.");
+        }
+        postRepository.deleteById(postId);
+    }
+}