답변 단건 -> 다건 조회 변경

Author: STGRAM\gffd9

src/main/java/com/oronaminc/join/answer/api/AnswerController.java

@@ -1,17 +1,22 @@
 package com.oronaminc.join.answer.api;
 
 import com.oronaminc.join.answer.dto.AnswerGetResponse;
+import com.oronaminc.join.answer.dto.AnswerListResponse;
+import com.oronaminc.join.answer.mapper.AnswerMapper;
 import com.oronaminc.join.answer.service.AnswerService;
 import com.oronaminc.join.member.security.MemberDetails;
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.responses.ApiResponse;
+import java.time.LocalDateTime;
 import lombok.RequiredArgsConstructor;
+import org.springframework.data.domain.Slice;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.security.core.annotation.AuthenticationPrincipal;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.ResponseStatus;
 import org.springframework.web.bind.annotation.RestController;
 
@@ -33,14 +38,19 @@ public class AnswerController {
     )
     @GetMapping("/rooms/{roomId}/questions/{questionId}/answers")
     @ResponseStatus(HttpStatus.OK)
-    public ResponseEntity<AnswerGetResponse> getAnswer(
+    public ResponseEntity<AnswerListResponse> getAnswers(
         @PathVariable Long roomId,
         @PathVariable Long questionId,
-        @AuthenticationPrincipal MemberDetails memberDetails
+        @AuthenticationPrincipal MemberDetails memberDetails,
+        @RequestParam(required = false) Long lastId,
+        @RequestParam(required = false) LocalDateTime lastCreatedAt,
+        @RequestParam(defaultValue = "10") int size
     ) {
         Long memberId = memberDetails.getId();
-        AnswerGetResponse response = answerService.getAnswer(roomId, questionId, memberId);
-        return ResponseEntity.ok(response);
+
+        Slice<AnswerGetResponse> response = answerService.getAnswers(roomId, questionId, memberId,
+            lastId, lastCreatedAt, size);
+        return ResponseEntity.ok(AnswerMapper.toAnswerListResponse(response));
     }
 
 }

src/main/java/com/oronaminc/join/answer/dao/AnswerRepository.java

@@ -1,35 +1,62 @@
 package com.oronaminc.join.answer.dao;
 
+import com.oronaminc.join.answer.domain.Answer;
+import com.oronaminc.join.question.domain.Question;
+import java.time.LocalDateTime;
 import java.util.List;
 import java.util.Optional;
+import org.springframework.data.domain.Pageable;
 import org.springframework.data.jpa.repository.JpaRepository;
-import com.oronaminc.join.answer.domain.Answer;
-import com.oronaminc.join.question.domain.Question;
 import org.springframework.data.jpa.repository.Query;
 import org.springframework.data.repository.query.Param;
 
 public interface AnswerRepository extends JpaRepository<Answer, Long> {
 
     Optional<Answer> findByQuestionId(Long questionId);
 
-    boolean existsByQuestionIdAndMemberId(Long questionId, Long memberId);
+    @Query("""
+            SELECT a
+            FROM Answer a
+            JOIN FETCH a.member m
+            WHERE a.question.id = :questionId
+            ORDER BY a.createdAt DESC, a.id DESC
+        """)
+    List<Answer> findFirstPageByQuestionId(
+        @Param("questionId") Long questionId,
+        Pageable pageable
+    );
+
+    @Query("""
+            SELECT a
+            FROM Answer a
+            JOIN FETCH a.member m
+            WHERE a.question.id = :questionId
+              AND (a.createdAt < :lastCreatedAt OR (a.createdAt = :lastCreatedAt AND a.id < :lastId))
+            ORDER BY a.createdAt DESC, a.id DESC
+        """)
+    List<Answer> findByQuestionIdWithCursor(
+        @Param("questionId") Long questionId,
+        @Param("lastCreatedAt") LocalDateTime lastCreatedAt,
+        @Param("lastId") Long lastId,
+        Pageable pageable
+    );
 
     void deleteByQuestionId(Long questionId);
 
     void deleteByQuestionIn(List<Question> questions);
 
     @Query("""
-        select count(distinct a.question.id)
-        from Answer a
-        where a.question.room.id = :roomId
-    """)
+            select count(distinct a.question.id)
+            from Answer a
+            where a.question.room.id = :roomId
+        """)
     Long countAnsweredQuestionsByRoomId(@Param("roomId") Long roomId);
 
     @Query("""
-        select a
-        from Answer a
-        where a.question.id in :questionIds
-    """)
+            select a
+            from Answer a
+            where a.question.id in :questionIds
+        """)
     List<Answer> findAllByQuestionIds(@Param("questionIds") List<Long> questionIds);
 
 }

src/main/java/com/oronaminc/join/answer/domain/Answer.java

@@ -26,7 +26,6 @@
 @Builder
 @AllArgsConstructor(access = AccessLevel.PRIVATE)
 @NoArgsConstructor(access = AccessLevel.PROTECTED)
-// TODO: ddl-auto: create,update에만 유효 -> 추후 flyway sql 생성
 @Table(name = "answer", indexes = {
     @Index(name = "idx_answer_question_member", columnList = "question_id, member_id")
 })

src/main/java/com/oronaminc/join/answer/dto/AnswerGetResponse.java

@@ -12,7 +12,7 @@ public record AnswerGetResponse(
     @Schema(description = "답변 내용에 대한 공감 수", example = "23")
     Long emojiCount,
     @Schema(description = "답변 공감 여부", example = "true")
-    boolean Emojied,
+    boolean isEmojied,
     @Schema(description = "답변 내용", example = "답변입니다.")
     String content,
     @Schema(description = "작성자 정보  DTO")

src/main/java/com/oronaminc/join/answer/dto/AnswerListResponse.java

@@ -0,0 +1,11 @@
+package com.oronaminc.join.answer.dto;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+import java.util.List;
+
+@Schema(description = "답변 목록을 묶기 위한 DTO")
+public record AnswerListResponse(
+    List<AnswerGetResponse> answers
+) {
+
+}

src/main/java/com/oronaminc/join/answer/mapper/AnswerMapper.java

@@ -1,15 +1,19 @@
 package com.oronaminc.join.answer.mapper;
 
 import com.oronaminc.join.answer.domain.Answer;
-import com.oronaminc.join.answer.dto.AnswerRequest;
 import com.oronaminc.join.answer.dto.AnswerCreateResponse;
 import com.oronaminc.join.answer.dto.AnswerGetResponse;
+import com.oronaminc.join.answer.dto.AnswerListResponse;
+import com.oronaminc.join.answer.dto.AnswerRequest;
 import com.oronaminc.join.answer.dto.AnswerUpdateResponse;
+import com.oronaminc.join.emoji.domain.TargetType;
+import com.oronaminc.join.emoji.service.EmojiReader;
 import com.oronaminc.join.global.dto.WriterDto;
 import com.oronaminc.join.member.domain.Member;
 import com.oronaminc.join.question.domain.Question;
 import lombok.AccessLevel;
 import lombok.NoArgsConstructor;
+import org.springframework.data.domain.Slice;
 
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public class AnswerMapper {
@@ -30,11 +34,12 @@ public static AnswerCreateResponse toAnswerCreateResponse(Answer answer) {
             .build();
     }
 
-    public static AnswerGetResponse toAnswerGetResponse(Answer answer, Long emojiCount, boolean isEmojied) {
+    public static AnswerGetResponse toAnswerGetResponse(Answer answer, boolean isEmojied) {
+
         return AnswerGetResponse.builder()
             .answerId(answer.getId())
-            .emojiCount(emojiCount)
-            .Emojied(isEmojied)
+            .emojiCount(answer.getEmojiCount())
+            .isEmojied(isEmojied)
             .content(answer.getContent())
             .writer(new WriterDto(
                 answer.getMember().getId(),
@@ -56,4 +61,9 @@ public static AnswerUpdateResponse toAnswerUpdateResponse(Answer answer) {
             .build();
     }
 
+    public static AnswerListResponse toAnswerListResponse(
+        Slice<AnswerGetResponse> slice) {
+        return new AnswerListResponse(slice.getContent());
+    }
+
 }

src/main/java/com/oronaminc/join/answer/service/AnswerReader.java

@@ -1,33 +1,36 @@
 package com.oronaminc.join.answer.service;
 
-import static com.oronaminc.join.global.exception.ErrorCode.*;
-
-import com.oronaminc.join.global.exception.ErrorCode;
-import com.oronaminc.join.room.domain.Room;
-import java.util.List;
-import java.util.Optional;
-
-import org.springframework.stereotype.Component;
-
 import com.oronaminc.join.answer.dao.AnswerRepository;
 import com.oronaminc.join.answer.domain.Answer;
+import com.oronaminc.join.global.exception.ErrorCode;
 import com.oronaminc.join.global.exception.ErrorException;
-
+import java.time.LocalDateTime;
+import java.util.List;
+import java.util.Optional;
 import lombok.RequiredArgsConstructor;
+import org.springframework.data.domain.Pageable;
+import org.springframework.stereotype.Component;
 
 @Component
 @RequiredArgsConstructor
 public class AnswerReader {
-    private final AnswerRepository answerRepository;
 
-    public boolean existsByQuestionIdAndMemberId(Long questionId, Long memberId) {
-        return answerRepository.existsByQuestionIdAndMemberId(questionId, memberId);
-    }
+    private final AnswerRepository answerRepository;
 
     public Optional<Answer> findById(Long answerId) {
         return answerRepository.findById(answerId);
     }
 
+    public List<Answer> getFirstPageByQuestionId(Long questionId, Pageable pageable) {
+        return answerRepository.findFirstPageByQuestionId(questionId, pageable);
+    }
+
+    public List<Answer> getAnswerByQuestionIdWithCursor(Long questionId,
+        LocalDateTime lastCreatedAt, Long lastId, Pageable pageable) {
+        return answerRepository.findByQuestionIdWithCursor(questionId, lastCreatedAt, lastId,
+            pageable);
+    }
+
     public Answer getByQuestionId(Long questionId) {
         return answerRepository.findByQuestionId(questionId)
             .orElseThrow(() -> new ErrorException(ErrorCode.NOT_FOUND_EXIST_ANSWER));

src/main/java/com/oronaminc/join/answer/service/AnswerService.java

@@ -9,15 +9,20 @@
 import com.oronaminc.join.answer.util.PermissionValidator;
 import com.oronaminc.join.emoji.domain.TargetType;
 import com.oronaminc.join.emoji.service.EmojiReader;
+import com.oronaminc.join.global.util.SliceUtil;
 import com.oronaminc.join.member.domain.Member;
 import com.oronaminc.join.member.service.MemberReader;
-import com.oronaminc.join.participant.service.ParticipantService;
 import com.oronaminc.join.question.domain.Question;
 import com.oronaminc.join.question.service.QuestionReader;
 import com.oronaminc.join.room.domain.Room;
 import com.oronaminc.join.room.service.RoomReader;
+import java.time.LocalDateTime;
 import java.util.List;
+import java.util.Set;
 import lombok.RequiredArgsConstructor;
+import org.springframework.data.domain.PageRequest;
+import org.springframework.data.domain.Pageable;
+import org.springframework.data.domain.Slice;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
@@ -48,18 +53,43 @@ public Answer create(Long roomId, Long memberId, Long questionId,
 
     }
 
-    @Transactional
-    public AnswerGetResponse getAnswer(Long roomId, Long questionId, Long memberId) {
-        Member member = memberReader.getById(memberId);
+    @Transactional(readOnly = true)
+    public Slice<AnswerGetResponse> getAnswers(
+        Long roomId,
+        Long questionId,
+        Long memberId,
+        Long lastId,
+        LocalDateTime lastCreatedAt,
+        int size
+    ) {
+        memberReader.getById(memberId);
         roomReader.getById(roomId);
         questionReader.getByIdAndRoomId(questionId, roomId);
-        Answer answer = answerReader.getByQuestionId(questionId);
+        answerReader.getByQuestionId(questionId);
+
+        Pageable pageable = PageRequest.of(0, size + 1);
+
+        List<Answer> answers = (lastCreatedAt == null || lastId == null)
+            ? answerReader.getFirstPageByQuestionId(questionId, pageable)
+            : answerReader.getAnswerByQuestionIdWithCursor(questionId, lastCreatedAt, lastId,
+                pageable);
+
+        // 공감 여부 일괄 조회
+        List<Long> answerIds = answers.stream().map(Answer::getId).toList();
+
+        Set<Long> emojiedAnswerIds = memberId != null
+            ? emojiReader.findTargetIdsByMemberAndTargetTypeInBatch(memberId, TargetType.ANSWER, answerIds)
+            : Set.of();
+
+        List<AnswerGetResponse> responseList = answers.stream()
+            .map(answer -> {
+                boolean isEmojied = emojiedAnswerIds.contains(answer.getId());
+                return AnswerMapper.toAnswerGetResponse(answer, isEmojied);
+            })
+            .toList();
 
-        Long emojiCount = answer.getEmojiCount();
-        boolean isEmojied = emojiReader.findByMemberIdAndTargetIdAndTargetType(member.getId(),
-            answer.getId(), TargetType.ANSWER).isPresent();
+        return SliceUtil.toSlice(responseList, PageRequest.of(0, size));
 
-        return AnswerMapper.toAnswerGetResponse(answer, emojiCount, isEmojied);
     }
 
     @Transactional

src/main/java/com/oronaminc/join/emoji/dao/EmojiRepository.java

@@ -2,8 +2,12 @@
 
 import com.oronaminc.join.emoji.domain.Emoji;
 import com.oronaminc.join.emoji.domain.TargetType;
+import java.util.List;
 import java.util.Optional;
+import java.util.Set;
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.query.Param;
 
 public interface EmojiRepository extends JpaRepository<Emoji, String> {
 
@@ -16,4 +20,17 @@ Optional<Emoji> findByMemberIdAndTargetIdAndTargetType(Long memberId, Long targe
 
     boolean existsByMemberIdAndTargetIdAndTargetType(Long memberId, Long targetId,
         TargetType targetType);
+
+    @Query("""
+            SELECT e.targetId
+            FROM Emoji e
+            WHERE e.member.id = :memberId
+              AND e.targetType = :targetType
+              AND e.targetId IN :targetIds
+        """)
+    Set<Long> findTargetIdsByMemberIdAndTargetTypeAndTargetIdIn(
+        @Param("memberId") Long memberId,
+        @Param("targetType") TargetType targetType,
+        @Param("targetIds") List<Long> targetIds
+    );
 }

src/main/java/com/oronaminc/join/emoji/service/EmojiReader.java

@@ -5,7 +5,9 @@
 import com.oronaminc.join.emoji.domain.TargetType;
 import com.oronaminc.join.global.exception.ErrorCode;
 import com.oronaminc.join.global.exception.ErrorException;
+import java.util.List;
 import java.util.Optional;
+import java.util.Set;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Component;
 
@@ -38,4 +40,9 @@ public boolean existsByMemberIdAndTargetIdAndTargetType(Long memberId, Long targ
             targetType);
     }
 
+    public Set<Long> findTargetIdsByMemberAndTargetTypeInBatch(Long memberId, TargetType targetType, List<Long> targetIds) {
+        if (targetIds.isEmpty() || targetType == null) return Set.of();
+        return emojiRepository.findTargetIdsByMemberIdAndTargetTypeAndTargetIdIn(memberId, targetType, targetIds);
+    }
+
 }