♻️Refactor: 커뮤니티 게시글 전체 조회 가능하도록 수정

src/main/java/com/sku/refit/domain/post/controller/PostController.java

@@ -68,9 +68,9 @@ ResponseEntity<BaseResponse<InfiniteResponse<PostDetailResponse>>> getPostByCate
                       type = "string",
                       allowableValues = {"FREE", "REPAIR", "INFO"},
                       example = "FREE"))
-          @RequestParam
+          @RequestParam(required = false)
           String category,
-      @Parameter(description = "마지막으로 조회한 게시글 식별자(첫 조회 시 생략)", example = "3")
+      @Parameter(description = "마지막으로 조회한 게시글 식별자(첫 조회 시 생략, 최신순이라서 식별자 값 감소)", example = "3")
           @RequestParam(required = false)
           Long lastPostId,
       @Parameter(description = "한 번에 조회할 게시글 개수", example = "3") @RequestParam(defaultValue = "3")

src/main/java/com/sku/refit/domain/post/repository/PostRepository.java

@@ -16,10 +16,9 @@ public interface PostRepository extends JpaRepository<Post, Long> {
 
   Page<Post> findByPostCategory(PostCategory category, Pageable pageable);
 
-  Page<Post> findByPostCategoryContainingAndIdLessThan(
-      String category, Long lastPostId, Pageable pageable);
-
   Page<Post> findAllByUser_Id(Long userId, Pageable pageable);
 
-  Page<Post> findAllByUser_IdAndIdLessThan(Long userId, Long lastPostId, Pageable pageable);
+  Page<Post> findByIdLessThan(Long id, Pageable pageable);
+
+  Page<Post> findByPostCategoryAndIdLessThan(PostCategory category, Long id, Pageable pageable);
 }

src/main/java/com/sku/refit/domain/post/service/PostServiceImpl.java

@@ -155,20 +155,28 @@ public InfiniteResponse<PostDetailResponse> getPostsByCategory(
     Pageable pageable = PageRequest.of(0, size + 1, Sort.by(Sort.Direction.DESC, "id"));
     List<Post> posts;
 
-    PostCategory postCategory;
-    try {
-      postCategory = PostCategory.valueOf(category);
-    } catch (IllegalArgumentException e) {
-      throw new CustomException(PostErrorCode.INVALID_CATEGORY);
-    }
-
-    if (lastPostId == null) {
-      posts = postRepository.findByPostCategory(postCategory, pageable).getContent();
+    if (category == null || category.isBlank()) {
+      if (lastPostId == null) {
+        posts = postRepository.findAll(pageable).getContent();
+      } else {
+        posts = postRepository.findByIdLessThan(lastPostId, pageable).getContent();
+      }
     } else {
-      posts =
-          postRepository
-              .findByPostCategoryContainingAndIdLessThan(category, lastPostId, pageable)
-              .getContent();
+      PostCategory postCategory;
+      try {
+        postCategory = PostCategory.valueOf(category);
+      } catch (IllegalArgumentException e) {
+        throw new CustomException(PostErrorCode.INVALID_CATEGORY);
+      }
+
+      if (lastPostId == null) {
+        posts = postRepository.findByPostCategory(postCategory, pageable).getContent();
+      } else {
+        posts =
+            postRepository
+                .findByPostCategoryAndIdLessThan(postCategory, lastPostId, pageable)
+                .getContent();
+      }
     }
 
     boolean hasNext = posts.size() > size;
@@ -204,7 +212,7 @@ public InfiniteResponse<PostDetailResponse> getPostsByCategory(
                         user))
             .toList();
 
-    Long newLastCursor = posts.isEmpty() ? null : posts.getLast().getId();
+    Long newLastCursor = posts.isEmpty() ? null : posts.get(posts.size() - 1).getId();
 
     log.info(
         "[POST CATEGORY LIST] category={}, lastPostId={}, size={}", category, lastPostId, size);