[feat] 특정 질문의 주변 (이전, 다음) 질문 절보 조회 API 구현

src/main/java/qp/official/qp/converter/QuestionConverter.java

@@ -128,4 +128,23 @@ public static UserQuestionAlarmResponseDTO.UserQuestionAlarmDTO toUserQuestionAl
             .createdAt(userQuestionAlarm.getCreatedAt())
             .build();
     }
+
+    public static QuestionResponseDTO.QuestionAdjacentDTO.QuestionAdjacentPreviewDTO toQuestionAdjacentPreviewDTO(Question question) {
+
+        if (question == null) return null;
+
+        return QuestionResponseDTO.QuestionAdjacentDTO.QuestionAdjacentPreviewDTO.builder()
+                .questionId(question.getQuestionId())
+                .title(question.getTitle())
+                .build();
+    }
+
+    public static QuestionResponseDTO.QuestionAdjacentDTO toQuestionAdjacentDTO(Question.QuestionAdjacent adjacent) {
+        return QuestionResponseDTO.QuestionAdjacentDTO.builder()
+                .hasOlder(adjacent.getOlderQuestion() != null)
+                .hasLater(adjacent.getLaterQuestion() != null)
+                .olderQuestion(toQuestionAdjacentPreviewDTO(adjacent.getOlderQuestion()))
+                .laterQuestion(toQuestionAdjacentPreviewDTO(adjacent.getLaterQuestion()))
+                .build();
+    }
 }

src/main/java/qp/official/qp/domain/Question.java

@@ -95,4 +95,13 @@ public void delete() {
         this.user.getQuestionList().remove(this);
         this.getQuestionHashTagList().forEach(questionHashTag -> questionHashTag.getHashtag().getQuestionHashTagList().remove(questionHashTag));
     }
+
+    @Builder
+    @Getter
+    @AllArgsConstructor
+    @NoArgsConstructor
+    public static class QuestionAdjacent{
+        Question laterQuestion;
+        Question olderQuestion;
+    }
 }

src/main/java/qp/official/qp/repository/QuestionRepository.java

@@ -8,10 +8,21 @@
 import qp.official.qp.domain.Question;
 import qp.official.qp.domain.User;
 
+import java.util.Optional;
+
 @Repository
 public interface QuestionRepository extends JpaRepository<Question, Long> {
     Page<Question> findAllByOrderByCreatedAtDescQuestionIdDesc(Pageable pageable);
     Page<Question> findAllByTitleContainingIgnoreCaseOrContentContainingIgnoreCaseOrderByCreatedAtDescQuestionIdDesc(String title,String content, Pageable pageable);
     Page<Question> findByUserOrderByCreatedAtDescQuestionIdDesc(User user, Pageable pageable);
     boolean existsByUser(User user);
+    /**
+     * OlderQuestionsByQuestionId
+     */
+    Optional<Question> findTopByQuestionIdLessThanOrderByCreatedAtDescQuestionIdDesc(Long questionId);
+
+    /**
+     * LaterQuestionsByQuestionId
+     * */
+    Optional<Question> findTopByQuestionIdGreaterThanOrderByCreatedAtAscQuestionIdAsc(Long questionId);
 }

src/main/java/qp/official/qp/service/QuestionService/QuestionQueryService.java

@@ -2,10 +2,10 @@
 
 import org.springframework.data.domain.Page;
 import qp.official.qp.domain.Question;
+import qp.official.qp.domain.mapping.UserQuestionAlarm;
 
 import java.util.List;
 import java.util.Optional;
-import qp.official.qp.domain.mapping.UserQuestionAlarm;
 
 public interface QuestionQueryService {
     Question findById(Long questionId);
@@ -18,4 +18,5 @@ public interface QuestionQueryService {
     Page<Question> findAlarmedQuestions(Long userId, int page, int size);
     Integer countExpertCountByQuestion(Question question);
 
+    Question.QuestionAdjacent findAdjacentQuestions(Long questionId);
 }

src/main/java/qp/official/qp/service/QuestionService/QuestionQueryServiceImpl.java

@@ -15,6 +15,7 @@
 import qp.official.qp.domain.mapping.UserQuestionAlarm;
 import qp.official.qp.repository.AnswerRepository;
 import qp.official.qp.repository.QuestionRepository;
+import qp.official.qp.repository.UserQuestionAlarmRepository;
 
 import java.util.List;
 import java.util.Optional;
@@ -107,4 +108,12 @@ public Integer countExpertCountByQuestion(Question question) {
         return answerRepository.countByQuestionAndUserRole(question, Role.EXPERT);
     }
 
+    @Override
+    public Question.QuestionAdjacent findAdjacentQuestions(Long questionId) {
+        return Question.QuestionAdjacent.builder()
+                .olderQuestion(questionRepository.findTopByQuestionIdLessThanOrderByCreatedAtDescQuestionIdDesc(questionId).orElse(null))
+                .laterQuestion(questionRepository.findTopByQuestionIdGreaterThanOrderByCreatedAtAscQuestionIdAsc(questionId).orElse(null))
+                .build();
+    }
+
 }

src/main/java/qp/official/qp/web/controller/QuestionController.java

@@ -77,6 +77,20 @@ public ApiResponse<QuestionResponseDTO.QuestionDTO> findQuestion(
         );
     }
 
+    // 특정 질문의 이전, 다음 질문 조회하는 API
+    @GetMapping("/{questionId}/adjacent")
+    @Operation(summary = "특정 질문 의 주변 Question 조회 API",description = "# path variable로 조회 할 questionId를 입력하세요.")
+    public ApiResponse<QuestionResponseDTO.QuestionAdjacentDTO> findAdjacentQuestions(
+            @PathVariable @ExistQuestion Long questionId
+    ) {
+        return ApiResponse.onSuccess(
+                SuccessStatus.Question_OK,
+                QuestionConverter.toQuestionAdjacentDTO(
+                        questionQueryService.findAdjacentQuestions(questionId)
+                )
+        );
+    }
+
     // 전체 질문 페이징 조회 (검색 가능)
     @GetMapping
     @Operation(summary = "전체 질문 조회 API",description = "# RequestParam으로 페이징 조회를 위한 page와 size를 입력하세요. 검색을 원할 경우 search를 입력하세요. \n " +

src/main/java/qp/official/qp/web/dto/QuestionResponseDTO.java

@@ -79,6 +79,26 @@ public static class QuestionPreviewListDTO {
         boolean isLast;
     }
 
+    @Builder
+    @Getter
+    @NoArgsConstructor
+    @AllArgsConstructor
+    public static class QuestionAdjacentDTO {
+        Boolean hasLater;
+        Boolean hasOlder;
+        QuestionAdjacentPreviewDTO laterQuestion;
+        QuestionAdjacentPreviewDTO olderQuestion;
+
+        @Builder
+        @Getter
+        @NoArgsConstructor
+        @AllArgsConstructor
+        public static class QuestionAdjacentPreviewDTO {
+            Long questionId;
+            String title;
+        }
+    }
+
     @Builder
     @Getter
     @NoArgsConstructor