[feat] 댓글 단건 조회 기능 구현#64

src/main/java/com/back/domain/post/comment/controller/CommentController.java

@@ -3,6 +3,7 @@
 import com.back.domain.post.comment.dto.request.CommentCreateRequestDto;
 import com.back.domain.post.comment.dto.response.CommentResponseDto;
 import com.back.domain.post.comment.service.CommentService;
+import com.back.domain.post.post.dto.response.PostResponseDto;
 import com.back.global.rsData.RsData;
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.tags.Tag;
@@ -48,4 +49,13 @@ public RsData<List<CommentResponseDto>> getComments(
   ) {
     return RsData.successOf(commentService.getComments(postId, lastId)); // code=200, message="success"
   }
+
+  @GetMapping("/{commentId}")
+  @Operation(summary = "댓글 단건 조회")
+  public RsData<CommentResponseDto> getComment(
+      @PathVariable Long postId,
+      @PathVariable Long commentId
+  ) {
+    return RsData.successOf(commentService.getComment(postId, commentId)); // code=200, message="success"
+  }
 }

src/main/java/com/back/domain/post/comment/service/CommentService.java

@@ -53,4 +53,17 @@ public List<CommentResponseDto> getComments(Long postId, Long lastId) {
           .toList();
     }
   }
+
+  // 댓글 단건 조회 로직
+  @Transactional(readOnly = true)
+  public CommentResponseDto getComment(Long postId, Long commentId) {
+    Comment comment = commentRepository.findById(commentId)
+        .orElseThrow(() -> new IllegalArgumentException("댓글이 존재하지 않습니다. id=" + commentId));
+
+    if (!comment.getPost().getId().equals(postId)) {
+      throw new IllegalStateException("댓글이 해당 게시글에 속하지 않습니다.");
+    }
+
+    return new CommentResponseDto(comment);
+  }
 }