[FEAT] 무한스크롤의 중복 컨텐츠 문제 해결

src/main/java/com/server/capple/domain/answer/controller/AnswerController.java

@@ -41,11 +41,13 @@ public BaseResponse<SliceResponse<AnswerInfo>> getAnswerList(
         @AuthMember Member member,
         @Parameter(description = "질문 식별자")
         @PathVariable(value = "questionId") Long questionId,
+        @Parameter(description = "Pull to Refresh 후 마지막 index")
+        @RequestParam(required = false) Long threshold,
         @Parameter(description = "조회할 페이지 번호<br>0부터 시작")
         @RequestParam(defaultValue = "0", required = false) Integer pageNumber,
         @Parameter(description = "조회할 페이지 크기")
         @RequestParam(defaultValue = "1000", required = false) Integer pageSize) {
-        return BaseResponse.onSuccess(answerService.getAnswerList(member.getId(), questionId, PageRequest.of(pageNumber, pageSize, Sort.by(Sort.Direction.DESC, "createdAt"))));
+        return BaseResponse.onSuccess(answerService.getAnswerList(member.getId(), questionId, threshold, PageRequest.of(pageNumber, pageSize, Sort.by(Sort.Direction.DESC, "createdAt"))));
     }
 
     @Operation(summary = "답변 수정 API", description = " 답변 수정 API 입니다." +
@@ -74,21 +76,25 @@ public BaseResponse<AnswerResponse.AnswerLike> toggleAnswerHeart(@AuthMember Mem
     @GetMapping
     public BaseResponse<SliceResponse<MemberAnswerInfo>> getMemberAnswer(
         @AuthMember Member member,
+        @Parameter(description = "Pull to Refresh 후 마지막 index")
+        @RequestParam(required = false) Long threshold,
         @Parameter(description = "조회할 페이지 번호<br>0부터 시작")
         @RequestParam(defaultValue = "0", required = false) Integer pageNumber,
         @Parameter(description = "조회할 페이지 크기")
         @RequestParam(defaultValue = "1000", required = false) Integer pageSize) {
-        return BaseResponse.onSuccess(answerService.getMemberAnswer(member, PageRequest.of(pageNumber, pageSize, Sort.by(Sort.Direction.DESC, "createdAt"))));
+        return BaseResponse.onSuccess(answerService.getMemberAnswer(member, threshold, PageRequest.of(pageNumber, pageSize, Sort.by(Sort.Direction.DESC, "createdAt"))));
     }
 
     @Operation(summary = "좋아한 답변 조회 API", description = " 좋아한 답변 조회 API 입니다.")
     @GetMapping("/heart")
     public BaseResponse<SliceResponse<MemberAnswerInfo>> getMemberHeartAnswer(
         @AuthMember Member member,
+        @Parameter(description = "Pull to Refresh 후 마지막 index")
+        @RequestParam(required = false) Long threshold,
         @Parameter(description = "조회할 페이지 번호<br>0부터 시작")
         @RequestParam(defaultValue = "0", required = false) Integer pageNumber,
         @Parameter(description = "조회할 페이지 크기")
         @RequestParam(defaultValue = "1000", required = false) Integer pageSize) {
-        return BaseResponse.onSuccess(answerService.getMemberHeartAnswer(member, PageRequest.of(pageNumber, pageSize, Sort.by(Sort.Direction.DESC, "createdAt"))));
+        return BaseResponse.onSuccess(answerService.getMemberHeartAnswer(member, threshold, PageRequest.of(pageNumber, pageSize, Sort.by(Sort.Direction.DESC, "createdAt"))));
     }
 }

src/main/java/com/server/capple/domain/answer/repository/AnswerRepository.java

@@ -16,19 +16,16 @@
 public interface AnswerRepository extends JpaRepository<Answer, Long> {
     Optional<Answer> findById(Long answerId);
 
-    Slice<Answer> findByIdIn(Set<Long> answerIds, Pageable pageable);
+    Slice<Answer> findByIdInAndIdIsLessThanEqual(Set<Long> answerIds, Long lastIndex, Pageable pageable);
 
     boolean existsByQuestionAndMember(Question question, Member member);
 
     @Query("SELECT a AS answer, (r IS NOT NULL) AS isReported " +
         "FROM Answer a " +
         "LEFT JOIN " +
         "Report r ON r.answer = a " +
-        "WHERE a.question.id = :questionId")
-    Slice<AnswerInfoInterface> findByQuestion(
-        @Param("questionId") Long questionId,
-        Pageable pageable);
+        "WHERE a.id <= :lastIndex AND a.question.id = :questionId")
+    Slice<AnswerInfoInterface> findByQuestion(@Param("questionId") Long questionId, Long lastIndex, Pageable pageable);
 
-    @Query("SELECT a FROM Answer a WHERE a.member = :member and a.deletedAt is null")
-    Slice<Answer> findByMember(@Param("member") Member member, Pageable pageable);
+    Slice<Answer> findByMemberAndIdIsLessThanEqual(@Param("member") Member member, Long lastIndex, Pageable pageable);
 }

src/main/java/com/server/capple/domain/answer/service/AnswerService.java

@@ -9,7 +9,6 @@
 import com.server.capple.global.common.SliceResponse;
 import org.springframework.data.domain.Pageable;
 
-
 public interface AnswerService {
     AnswerResponse.AnswerId createAnswer(Member member, Long questionId, AnswerRequest request);
 
@@ -21,9 +20,9 @@ public interface AnswerService {
 
     AnswerResponse.AnswerLike toggleAnswerHeart(Member loginMember, Long answerId);
 
-    SliceResponse<AnswerInfo> getAnswerList(Long memberId, Long questionId, Pageable pageable);
+    SliceResponse<AnswerInfo> getAnswerList(Long memberId, Long questionId, Long lastIndex, Pageable pageable);
 
-    SliceResponse<MemberAnswerInfo> getMemberAnswer(Member member, Pageable pageable);
+    SliceResponse<MemberAnswerInfo> getMemberAnswer(Member member, Long lastIndex, Pageable pageable);
 
-    SliceResponse<MemberAnswerInfo> getMemberHeartAnswer(Member member, Pageable pageable);
+    SliceResponse<MemberAnswerInfo> getMemberHeartAnswer(Member member, Long lastIndex, Pageable pageable);
 }

src/main/java/com/server/capple/domain/answer/service/AnswerServiceImpl.java

@@ -86,14 +86,16 @@ public AnswerResponse.AnswerId deleteAnswer(Member loginMember, Long answerId) {
     @Override
     public AnswerLike toggleAnswerHeart(Member loginMember, Long answerId) {
         Member member = memberService.findMember(loginMember.getId());
-
+        answerRepository.findById(answerId).orElseThrow(() -> new RestApiException(AnswerErrorCode.ANSWER_NOT_FOUND));
         Boolean isLiked = answerHeartRedisRepository.toggleAnswerHeart(member.getId(), answerId);
         return new AnswerLike(answerId, isLiked);
     }
 
     @Override
-    public SliceResponse<AnswerInfo> getAnswerList(Long memberId, Long questionId, Pageable pageable) {
-        Slice<AnswerInfoInterface> answerInfoSliceInterface = answerRepository.findByQuestion(questionId, pageable);
+    public SliceResponse<AnswerInfo> getAnswerList(Long memberId, Long questionId, Long lastIndex, Pageable pageable) {
+        lastIndex = getLastIndex(lastIndex);
+        Slice<AnswerInfoInterface> answerInfoSliceInterface = answerRepository.findByQuestion(questionId, lastIndex, pageable);
+        lastIndex = getLastIndexFromAnswerInfoInterface(lastIndex, answerInfoSliceInterface);
         return SliceResponse.toSliceResponse(answerInfoSliceInterface, answerInfoSliceInterface.getContent().stream().map(
             answerInfoDto -> answerMapper.toAnswerInfo(
                 answerInfoDto.getAnswer(),
@@ -102,33 +104,37 @@ public SliceResponse<AnswerInfo> getAnswerList(Long memberId, Long questionId, P
                 answerHeartRedisRepository.isMemberLikedAnswer(memberId, answerInfoDto.getAnswer().getId()),
                 answerInfoDto.getAnswer().getMember().getId().equals(memberId)
             )
-        ).toList(), null);
+        ).toList(), lastIndex.toString(), null);
     }
 
     // 유저가 작성한 답변 조회
     @Override
-    public SliceResponse<MemberAnswerInfo> getMemberAnswer(Member member, Pageable pageable) {
-        Slice<Answer> answerSlice = answerRepository.findByMember(member, pageable);
+    public SliceResponse<MemberAnswerInfo> getMemberAnswer(Member member, Long lastIndex, Pageable pageable) {
+        lastIndex = getLastIndex(lastIndex);
+        Slice<Answer> answerSlice = answerRepository.findByMemberAndIdIsLessThanEqual(member, lastIndex, pageable);
+        lastIndex = getLastIndexFromAnswer(lastIndex, answerSlice);
         return SliceResponse.toSliceResponse(
             answerSlice, answerSlice.getContent().stream()
                 .map(answer -> answerMapper.toMemberAnswerInfo(
                     answer,
                     answerHeartRedisRepository.getAnswerHeartsCount(answer.getId()),
                     answerHeartRedisRepository.isMemberLikedAnswer(member.getId(), answer.getId())
-                )).toList(), null
+                )).toList(), lastIndex.toString(), null
         );
     }
 
-    // 유저가 좋아한 답변 조회
+    // 유저가 좋아한 답변 조회 //TODO 좋아요니까 좋아요한 순으로 정렬해야할거같은데 Answer의 createAt으로 하고 있음
     @Override
-    public SliceResponse<MemberAnswerInfo> getMemberHeartAnswer(Member member, Pageable pageable) {
-        Slice<Answer> answerSlice = answerRepository.findByIdIn(answerHeartRedisRepository.getMemberHeartsAnswer(member.getId()), pageable);
+    public SliceResponse<MemberAnswerInfo> getMemberHeartAnswer(Member member, Long lastIndex, Pageable pageable) {
+        lastIndex = getLastIndex(lastIndex);
+        Slice<Answer> answerSlice = answerRepository.findByIdInAndIdIsLessThanEqual(answerHeartRedisRepository.getMemberHeartsAnswer(member.getId()), lastIndex, pageable);
+        lastIndex = getLastIndexFromAnswer(lastIndex, answerSlice);
         return SliceResponse.toSliceResponse(answerSlice, answerSlice.getContent().stream()
             .map(answer -> answerMapper.toMemberAnswerInfo(
                 answer,
                 answerHeartRedisRepository.getAnswerHeartsCount(answer.getId()),
                 answerHeartRedisRepository.isMemberLikedAnswer(member.getId(), answer.getId())
-            )).toList(), null
+            )).toList(), lastIndex.toString(), null
         );
     }
 
@@ -146,4 +152,16 @@ public Answer findAnswer(Long answerId) {
             () -> new RestApiException(AnswerErrorCode.ANSWER_NOT_FOUND)
         );
     }
+
+    private Long getLastIndex(Long lastIndex) {
+        return lastIndex == null ? Long.MAX_VALUE : lastIndex;
+    }
+
+    private Long getLastIndexFromAnswerInfoInterface(Long lastIndex, Slice<AnswerInfoInterface> answerInfoSliceInterface) {
+        return lastIndex == Long.MAX_VALUE ? answerInfoSliceInterface.stream().map(AnswerInfoInterface::getAnswer).map(Answer::getId).max(Long::compareTo).get() : lastIndex;
+    }
+
+    private Long getLastIndexFromAnswer(Long lastIndex, Slice<Answer> answerSlice) {
+        return lastIndex == Long.MAX_VALUE ? answerSlice.stream().map(Answer::getId).max(Long::compareTo).get() : lastIndex;
+    }
 }

src/main/java/com/server/capple/domain/board/controller/BoardController.java

@@ -11,6 +11,7 @@
 import com.server.capple.global.common.BaseResponse;
 import com.server.capple.global.common.SliceResponse;
 import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.Parameter;
 import io.swagger.v3.oas.annotations.responses.ApiResponse;
 import io.swagger.v3.oas.annotations.responses.ApiResponses;
 import io.swagger.v3.oas.annotations.tags.Tag;
@@ -46,9 +47,11 @@ private BaseResponse<BoardId> createBoard(@AuthMember Member member,
     private BaseResponse<SliceResponse<BoardInfo>> getBoardsByBoardTypeWithRedis(
             @AuthMember Member member,
             @RequestParam(name = "boardType", required = false) BoardType boardType,
+            @Parameter(description = "Pull to Refresh 후 마지막 index")
+            @RequestParam(required = false) Long threshold,
             @RequestParam(defaultValue = "0", required = false) Integer pageNumber, @RequestParam(defaultValue = "1000", required = false) Integer pageSize
     ) {
-        return BaseResponse.onSuccess(boardService.getBoardsByBoardTypeWithRedis(member, boardType, PageRequest.of(pageNumber, pageSize, Sort.by(Sort.Direction.DESC, "createdAt"))));
+        return BaseResponse.onSuccess(boardService.getBoardsByBoardTypeWithRedis(member, boardType, threshold, PageRequest.of(pageNumber, pageSize, Sort.by(Sort.Direction.DESC, "createdAt"))));
     }
 
     @Operation(summary = "카테고리별 게시글 조회", description = "카테고리별 게시글을 조회합니다.")
@@ -59,9 +62,11 @@ private BaseResponse<SliceResponse<BoardInfo>> getBoardsByBoardTypeWithRedis(
     private BaseResponse<SliceResponse<BoardInfo>> getBoardsByBoardType(
             @AuthMember Member member,
             @RequestParam(name = "boardType", required = false) BoardType boardType,
+            @Parameter(description = "Pull to Refresh 후 마지막 index")
+            @RequestParam(required = false) Long threshold,
             @RequestParam(defaultValue = "0", required = false) Integer pageNumber, @RequestParam(defaultValue = "1000", required = false) Integer pageSize
     ) {
-        return BaseResponse.onSuccess(boardService.getBoardsByBoardType(member, boardType, PageRequest.of(pageNumber, pageSize, Sort.by(Sort.Direction.DESC, "createdAt"))));
+        return BaseResponse.onSuccess(boardService.getBoardsByBoardType(member, boardType, threshold, PageRequest.of(pageNumber, pageSize, Sort.by(Sort.Direction.DESC, "createdAt"))));
     }
 
     @Operation(summary = "게시글 검색 API", description = "게시글을 검색합니다. 자유게시판에서만 검색이 가능합니다.")
@@ -71,9 +76,11 @@ private BaseResponse<SliceResponse<BoardInfo>> getBoardsByBoardType(
     @GetMapping("/search")
     private BaseResponse<SliceResponse<BoardInfo>> searchBoardsByKeyword(
             @AuthMember Member member, @RequestParam(name = "keyword") String keyword,
+            @Parameter(description = "Pull to Refresh 후 마지막 index")
+            @RequestParam(required = false) Long threshold,
             @RequestParam(defaultValue = "0", required = false) Integer pageNumber,
             @RequestParam(defaultValue = "1000", required = false) Integer pageSize) {
-        return BaseResponse.onSuccess(boardService.searchBoardsByKeyword(member, keyword, PageRequest.of(pageNumber, pageSize, Sort.by(Sort.Direction.DESC, "createdAt"))));
+        return BaseResponse.onSuccess(boardService.searchBoardsByKeyword(member, keyword, threshold, PageRequest.of(pageNumber, pageSize, Sort.by(Sort.Direction.DESC, "createdAt"))));
     }
 
 

src/main/java/com/server/capple/domain/board/repository/BoardRepository.java

@@ -9,33 +9,31 @@
 import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.data.jpa.repository.Query;
 
-import java.util.List;
-
 public interface BoardRepository extends JpaRepository<Board, Long> {
 
     @Query("SELECT DISTINCT b AS board, " +
             "(CASE WHEN bh.isLiked = TRUE THEN TRUE ELSE FALSE END) AS isLike, " +
             "(CASE WHEN b.writer = :member THEN TRUE ELSE FALSE END) AS isMine " +
             "FROM Board b " +
             "LEFT JOIN BoardHeart bh ON b = bh.board AND bh.member = :member " +
-            "WHERE :boardType IS NULL OR b.boardType = :boardType")
-    Slice<BoardInfoInterface> findBoardInfosByMemberAndBoardType(Member member, BoardType boardType, Pageable pageable);
+            "WHERE (:boardType IS NULL OR b.boardType = :boardType) AND b.id <= :lastIndex")
+    Slice<BoardInfoInterface> findBoardInfosByMemberAndBoardTypeAndIdIsLessThanEqual(Member member, BoardType boardType, Long lastIndex, Pageable pageable);
 
     @Query("SELECT DISTINCT b AS board, " +
             "(CASE WHEN bh.isLiked = TRUE THEN TRUE ELSE FALSE END) AS isLike, " +
             "(CASE WHEN b.writer = :member THEN TRUE ELSE FALSE END) AS isMine " +
             "FROM Board b " +
             "LEFT JOIN BoardHeart bh ON b = bh.board AND bh.member = :member " +
-            "WHERE b.content LIKE %:keyword% AND b.boardType = 0 ORDER BY b.createdAt DESC") //FREETYPE = 0
-    Slice<BoardInfoInterface> findBoardInfosByMemberAndKeyword(Member member, String keyword, Pageable pageable);
+            "WHERE b.id <= :lastIndex AND b.content LIKE %:keyword% AND b.boardType = 0") //FREETYPE = 0
+    Slice<BoardInfoInterface> findBoardInfosByMemberAndKeywordAndIdIsLessThanEqual(Member member, String keyword, Long lastIndex, Pageable pageable);
 
 
     //redis 성능 테스트용
     @Query("SELECT DISTINCT b AS board, " +
             "(CASE WHEN b.writer = :member THEN TRUE ELSE FALSE END) AS isMine " +
             "FROM Board b " +
-            "WHERE :boardType IS NULL OR b.boardType = :boardType ORDER BY b.createdAt DESC")
-    Slice<BoardInfoInterface> findBoardInfosForRedis(Member member, BoardType boardType, Pageable pageable);
+            "WHERE (:boardType IS NULL OR b.boardType = :boardType) AND b.id <= :lastIndex")
+    Slice<BoardInfoInterface> findBoardInfosForRedisAndIdIsLessThanEqual(Member member, BoardType boardType, Long lastIndex, Pageable pageable);
 
     @Query("SELECT COUNT(b) FROM Board b")
     Integer getBoardCount();

src/main/java/com/server/capple/domain/board/service/BoardService.java

@@ -13,11 +13,11 @@
 public interface BoardService {
     BoardId createBoard(Member member, BoardType boardType, String content);
 
-    SliceResponse<BoardInfo> getBoardsByBoardTypeWithRedis(Member member, BoardType boardType, Pageable pageable);
+    SliceResponse<BoardInfo> getBoardsByBoardTypeWithRedis(Member member, BoardType boardType, Long lastIndex, Pageable pageable);
 
-    SliceResponse<BoardInfo> getBoardsByBoardType(Member member, BoardType boardType, Pageable pageable);
+    SliceResponse<BoardInfo> getBoardsByBoardType(Member member, BoardType boardType, Long lastIndex, Pageable pageable);
 
-    SliceResponse<BoardInfo> searchBoardsByKeyword(Member member, String keyword, Pageable pageable);
+    SliceResponse<BoardInfo> searchBoardsByKeyword(Member member, String keyword, Long lastIndex, Pageable pageable);
 
     BoardId deleteBoard(Member member, Long boardId);