Feat: 게시글 다건/단건 조회 API 구현

Author: joyewon0705

src/main/java/com/back/domain/board/controller/PostController.java

@@ -1,12 +1,14 @@
 package com.back.domain.board.controller;
 
-import com.back.domain.board.dto.PostRequest;
-import com.back.domain.board.dto.PostResponse;
+import com.back.domain.board.dto.*;
 import com.back.domain.board.service.PostService;
 import com.back.global.common.dto.RsData;
 import com.back.global.security.user.CustomUserDetails;
 import jakarta.validation.Valid;
 import lombok.RequiredArgsConstructor;
+import org.springframework.data.domain.Pageable;
+import org.springframework.data.domain.Sort;
+import org.springframework.data.web.PageableDefault;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.security.core.annotation.AuthenticationPrincipal;
@@ -32,4 +34,35 @@ public ResponseEntity<RsData<PostResponse>> createPost(
                         response
                 ));
     }
+
+    // 게시글 다건 조회
+    @GetMapping
+    public ResponseEntity<RsData<PageResponse<PostListResponse>>> getPosts(
+            @PageableDefault(sort = "createdAt", direction = Sort.Direction.DESC) Pageable pageable,
+            @RequestParam(required = false) String keyword,
+            @RequestParam(required = false) String searchType,
+            @RequestParam(required = false) Long categoryId
+    ) {
+        PageResponse<PostListResponse> response = postService.getPosts(keyword, searchType, categoryId, pageable);
+        return ResponseEntity
+                .status(HttpStatus.OK)
+                .body(RsData.success(
+                        "게시글 목록이 조회되었습니다.",
+                        response
+                ));
+    }
+
+    // 게시글 단건 조회
+    @GetMapping("/{postId}")
+    public ResponseEntity<RsData<PostDetailResponse>> getPost(
+            @PathVariable Long postId
+    ) {
+        PostDetailResponse response = postService.getPost(postId);
+        return ResponseEntity
+                .status(HttpStatus.OK)
+                .body(RsData.success(
+                        "게시글이 조회되었습니다.",
+                        response
+                ));
+    }
 }

src/main/java/com/back/domain/board/dto/PageResponse.java

@@ -0,0 +1,36 @@
+package com.back.domain.board.dto;
+
+import org.springframework.data.domain.Page;
+
+import java.util.List;
+
+/**
+ * 페이지 응답 DTO
+ *
+ * @param items         목록 데이터
+ * @param page          현재 페이지 번호
+ * @param size          페이지 크기
+ * @param totalElements 전체 요소 수
+ * @param totalPages    전체 페이지 수
+ * @param last          마지막 페이지 여부
+ * @param <T>           제네릭 타입
+ */
+public record PageResponse<T>(
+        List<T> items,
+        int page,
+        int size,
+        long totalElements,
+        int totalPages,
+        boolean last
+) {
+    public static <T> PageResponse<T> from(Page<T> page) {
+        return new PageResponse<>(
+                page.getContent(),
+                page.getNumber(),
+                page.getSize(),
+                page.getTotalElements(),
+                page.getTotalPages(),
+                page.isLast()
+        );
+    }
+}

src/main/java/com/back/domain/board/dto/PostDetailResponse.java

@@ -0,0 +1,50 @@
+package com.back.domain.board.dto;
+
+import com.back.domain.board.entity.Post;
+
+import java.time.LocalDateTime;
+import java.util.List;
+
+/**
+ * 게시글 상세 응답 DTO
+ *
+ * @param postId        게시글 ID
+ * @param author        작성자 정보
+ * @param title         게시글 제목
+ * @param content       게시글 내용
+ * @param categories    게시글 카테고리 목록
+ * @param likeCount     좋아요 수
+ * @param bookmarkCount 북마크 수
+ * @param commentCount  댓글 수
+ * @param createdAt     게시글 생성 일시
+ * @param updatedAt     게시글 수정 일시
+ */
+public record PostDetailResponse(
+        Long postId,
+        AuthorResponse author,
+        String title,
+        String content,
+        List<CategoryResponse> categories,
+        long likeCount,
+        long bookmarkCount,
+        long commentCount,
+        LocalDateTime createdAt,
+        LocalDateTime updatedAt
+) {
+    public static PostDetailResponse from(Post post) {
+        return new PostDetailResponse(
+                post.getId(),
+                AuthorResponse.from(post.getUser()),
+                post.getTitle(),
+                post.getContent(),
+                post.getCategories().stream()
+                        .map(CategoryResponse::from)
+                        .toList(),
+                post.getPostLikes().size(),
+                post.getPostBookmarks().size(),
+                post.getComments().size(),
+                post.getCreatedAt(),
+                post.getUpdatedAt()
+        );
+    }
+}

src/main/java/com/back/domain/board/dto/PostListResponse.java

@@ -0,0 +1,77 @@
+package com.back.domain.board.dto;
+
+import com.querydsl.core.annotations.QueryProjection;
+import lombok.Getter;
+import lombok.Setter;
+
+import java.time.LocalDateTime;
+import java.util.List;
+
+/**
+ * 게시글 목록 응답 DTO
+ */
+@Getter
+public class PostListResponse {
+    private final Long postId;
+    private final AuthorResponse author;
+    private final String title;
+    private final long likeCount;
+    private final long bookmarkCount;
+    private final long commentCount;
+    private final LocalDateTime createdAt;
+    private final LocalDateTime updatedAt;
+
+    @Setter
+    private List<CategoryResponse> categories;
+
+    @QueryProjection
+    public PostListResponse(Long postId,
+                            AuthorResponse author,
+                            String title,
+                            List<CategoryResponse> categories,
+                            long likeCount,
+                            long bookmarkCount,
+                            long commentCount,
+                            LocalDateTime createdAt,
+                            LocalDateTime updatedAt) {
+        this.postId = postId;
+        this.author = author;
+        this.title = title;
+        this.categories = categories;
+        this.likeCount = likeCount;
+        this.bookmarkCount = bookmarkCount;
+        this.commentCount = commentCount;
+        this.createdAt = createdAt;
+        this.updatedAt = updatedAt;
+    }
+
+    /**
+     * 작성자 응답 DTO
+     */
+    @Getter
+    public static class AuthorResponse {
+        private final Long id;
+        private final String nickname;
+
+        @QueryProjection
+        public AuthorResponse(Long userId, String nickname) {
+            this.id = userId;
+            this.nickname = nickname;
+        }
+    }
+
+    /**
+     * 카테고리 응답 DTO
+     */
+    @Getter
+    public static class CategoryResponse {
+        private final Long id;
+        private final String name;
+
+        @QueryProjection
+        public CategoryResponse(Long id, String name) {
+            this.id = id;
+            this.name = name;
+        }
+    }
+}

src/main/java/com/back/domain/board/repository/PostRepository.java

@@ -5,5 +5,5 @@
 import org.springframework.stereotype.Repository;
 
 @Repository
-public interface PostRepository extends JpaRepository<Post, Long> {
+public interface PostRepository extends JpaRepository<Post, Long>, PostRepositoryCustom {
 }

src/main/java/com/back/domain/board/repository/PostRepositoryCustom.java

@@ -0,0 +1,9 @@
+package com.back.domain.board.repository;
+
+import com.back.domain.board.dto.PostListResponse;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
+
+public interface PostRepositoryCustom {
+    Page<PostListResponse> searchPosts(String keyword, String searchType, Long categoryId, Pageable pageable);
+}