feat: 백문백답 목록 조회 API를 구현한다.

src/main/java/com/dnd/accompany/domain/qna100/api/QnaController.java

@@ -11,6 +11,9 @@
 import com.dnd.accompany.domain.auth.dto.jwt.JwtAuthentication;
 import com.dnd.accompany.domain.qna100.api.dto.CreateAndUpdateQnaRequest;
 import com.dnd.accompany.domain.qna100.api.dto.DeleteQnaRequest;
+import com.dnd.accompany.domain.qna100.api.dto.PageRequest;
+import com.dnd.accompany.domain.qna100.api.dto.PageResponse;
+import com.dnd.accompany.domain.qna100.api.dto.QnaThumbnail;
 import com.dnd.accompany.domain.qna100.service.QnaService;
 
 import io.swagger.v3.oas.annotations.Operation;
@@ -31,7 +34,7 @@ public class QnaController {
 	public ResponseEntity<Void> createAndUpdate(
 		@RequestBody @Valid CreateAndUpdateQnaRequest request,
 		@AuthenticationPrincipal JwtAuthentication user) {
-		qnaService.saveAndUpdate(user.getId(), request);
+		qnaService.upsert(user.getId(), request);
 		return ResponseEntity.ok().build();
 	}
 
@@ -43,4 +46,12 @@ public ResponseEntity<Void> delete(
 		qnaService.delete(user.getId(), request);
 		return ResponseEntity.ok().build();
 	}
+
+	@Operation(summary = "백문백답 목록 조회")
+	@PostMapping("/all")
+	public ResponseEntity<PageResponse<QnaThumbnail>> readAll(
+		@RequestBody @Valid PageRequest request,
+		@AuthenticationPrincipal JwtAuthentication user) {
+		return ResponseEntity.ok(qnaService.getAllQnas(user.getId(), request));
+	}
 }

src/main/java/com/dnd/accompany/domain/qna100/api/dto/FindSlicesResult.java

@@ -0,0 +1,36 @@
+package com.dnd.accompany.domain.qna100.api.dto;
+
+import java.util.List;
+
+import org.springframework.data.domain.PageRequest;
+import org.springframework.data.domain.Slice;
+import org.springframework.data.domain.SliceImpl;
+
+import lombok.AccessLevel;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.experimental.SuperBuilder;
+
+@Getter
+@AllArgsConstructor(access = AccessLevel.PROTECTED)
+@SuperBuilder
+public abstract class FindSlicesResult {
+	private final Long cursor;
+
+	public static <T extends FindSlicesResult> Long getLastCursor(List<T> result) {
+		if (result.isEmpty())
+			return null;
+
+		return result.get(result.size() - 1).getCursor();
+	}
+
+	public static <T extends FindSlicesResult> Slice<T> createSlice(int size, List<T> content) {
+		boolean hasNext = content.size() > size;
+
+		if (hasNext) {
+			content.remove(content.size() - 1);
+		}
+
+		return new SliceImpl<>(content, PageRequest.of(0, size), hasNext);
+	}
+}

src/main/java/com/dnd/accompany/domain/qna100/api/dto/PageRequest.java

@@ -0,0 +1,30 @@
+package com.dnd.accompany.domain.qna100.api.dto;
+
+import com.querydsl.core.BooleanBuilder;
+import com.querydsl.core.types.dsl.NumberPath;
+import com.querydsl.core.types.dsl.StringTemplate;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+
+public record PageRequest(
+	@Schema(nullable = true) Long cursor,
+	@Schema(nullable = true) Integer size
+) {
+
+	public PageRequest {
+		if (size == null) {
+			size = 10;
+		}
+	}
+
+	public static BooleanBuilder cursorCondition(Long cursor, NumberPath<Long> nextCursor) {
+		BooleanBuilder builder = new BooleanBuilder();
+
+		if (cursor == null)
+			return builder;
+
+		builder.and(nextCursor.gt(cursor));
+
+		return builder;
+	}
+}

src/main/java/com/dnd/accompany/domain/qna100/api/dto/PageResponse.java

@@ -0,0 +1,10 @@
+package com.dnd.accompany.domain.qna100.api.dto;
+
+import java.util.List;
+
+public record PageResponse<T>(
+	boolean hasNext,
+	List<T> data,
+	Long cursor
+) {
+}

src/main/java/com/dnd/accompany/domain/qna100/api/dto/QnaThumbnail.java

@@ -0,0 +1,30 @@
+package com.dnd.accompany.domain.qna100.api.dto;
+
+import com.dnd.accompany.domain.qna100.entity.Qna100;
+
+import lombok.Getter;
+import lombok.experimental.SuperBuilder;
+
+@Getter
+@SuperBuilder
+public class QnaThumbnail extends FindSlicesResult {
+	private Long id;
+	private String question;
+	private String answer;
+
+	public QnaThumbnail(Long id, String question, String answer) {
+		super(id);
+
+		this.id = id;
+		this.question = question;
+		this.answer = answer;
+	}
+
+	public QnaThumbnail fromEntity(Qna100 qna100) {
+		return QnaThumbnail.builder()
+			.id(qna100.getId())
+			.question(qna100.getQuestion())
+			.answer(qna100.getAnswer())
+			.build();
+	}
+}

src/main/java/com/dnd/accompany/domain/qna100/infrastructure/querydsl/QnaRepositoryImpl.java

@@ -1,8 +1,17 @@
 package com.dnd.accompany.domain.qna100.infrastructure.querydsl;
 
+import static com.dnd.accompany.domain.qna100.api.dto.FindSlicesResult.*;
+import static com.dnd.accompany.domain.qna100.api.dto.PageRequest.*;
+import static com.dnd.accompany.domain.qna100.entity.QQna100.*;
+
+import java.util.List;
+
+import org.springframework.data.domain.Slice;
 import org.springframework.stereotype.Repository;
 
+import com.dnd.accompany.domain.qna100.api.dto.QnaThumbnail;
 import com.dnd.accompany.domain.qna100.infrastructure.querydsl.interfaces.QnaRepositoryCustom;
+import com.querydsl.core.types.Projections;
 import com.querydsl.jpa.impl.JPAQueryFactory;
 
 import lombok.RequiredArgsConstructor;
@@ -13,6 +22,21 @@ public class QnaRepositoryImpl implements QnaRepositoryCustom {
 
 	private final JPAQueryFactory queryFactory;
 
-
-
+	@Override
+	public Slice<QnaThumbnail> findQnaThumbnails(Long cursor, int size, Long userId) {
+		List<QnaThumbnail> content = queryFactory
+			.select(Projections.constructor(QnaThumbnail.class,
+				qna100.id,
+				qna100.question,
+				qna100.answer
+			))
+			.from(qna100)
+			.where(qna100.userId.eq(userId))
+			.where(cursorCondition(cursor, qna100.id))
+			.orderBy(qna100.id.asc())
+			.limit(size + 1)
+			.fetch();
+
+		return createSlice(size, content);
+	}
 }

src/main/java/com/dnd/accompany/domain/qna100/infrastructure/querydsl/interfaces/QnaRepositoryCustom.java

@@ -1,5 +1,9 @@
 package com.dnd.accompany.domain.qna100.infrastructure.querydsl.interfaces;
 
-public interface QnaRepositoryCustom {
+import org.springframework.data.domain.Slice;
+
+import com.dnd.accompany.domain.qna100.api.dto.QnaThumbnail;
 
+public interface QnaRepositoryCustom {
+	Slice<QnaThumbnail> findQnaThumbnails(Long cursor, int size, Long userId);
 }

src/main/java/com/dnd/accompany/domain/qna100/service/QnaService.java

@@ -1,16 +1,21 @@
 package com.dnd.accompany.domain.qna100.service;
 
+import static com.dnd.accompany.domain.qna100.api.dto.FindSlicesResult.*;
 import static java.util.stream.Collectors.*;
 
 import java.util.List;
 import java.util.Map;
 import java.util.function.Function;
 
+import org.springframework.data.domain.Slice;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
 import com.dnd.accompany.domain.qna100.api.dto.CreateAndUpdateQnaRequest;
 import com.dnd.accompany.domain.qna100.api.dto.DeleteQnaRequest;
+import com.dnd.accompany.domain.qna100.api.dto.PageRequest;
+import com.dnd.accompany.domain.qna100.api.dto.PageResponse;
+import com.dnd.accompany.domain.qna100.api.dto.QnaThumbnail;
 import com.dnd.accompany.domain.qna100.entity.Qna100;
 import com.dnd.accompany.domain.qna100.exception.Qna100AccessDeniedException;
 import com.dnd.accompany.domain.qna100.exception.Qna100NotFoundException;
@@ -26,7 +31,7 @@ public class QnaService {
 	private final QnaRepository qnaRepository;
 
 	@Transactional
-	public void saveAndUpdate(Long userId, CreateAndUpdateQnaRequest request) {
+	public void upsert(Long userId, CreateAndUpdateQnaRequest request) {
 		Map<Boolean, List<Qna100>> qnaMap = request.toMap(userId, request.qnas());
 
 		List<Qna100> newQnas = qnaMap.get(true);
@@ -51,10 +56,19 @@ public void delete(Long userId, DeleteQnaRequest request) {
 		Qna100 qna = qnaRepository.findFirstByUserId(userId)
 			.orElseThrow(() -> new Qna100NotFoundException(ErrorCode.QNA100_NOT_FOUND));
 
-		if(!userId.equals(qna.getUserId())){
+		if (!userId.equals(qna.getUserId())) {
 			throw new Qna100AccessDeniedException(ErrorCode.QNA100_ACCESS_DENIED);
 		}
 
 		qnaRepository.deleteByIdIn(request.ids());
 	}
+
+	@Transactional(readOnly = true)
+	public PageResponse<QnaThumbnail> getAllQnas(Long userId, PageRequest request) {
+		Slice<QnaThumbnail> sliceResult = qnaRepository.findQnaThumbnails(request.cursor(), request.size(), userId);
+
+		List<QnaThumbnail> qnaThumbnails = sliceResult.getContent();
+
+		return new PageResponse<>(sliceResult.hasNext(), qnaThumbnails, getLastCursor(qnaThumbnails));
+	}
 }