[프로젝트] 채팅 querydsl 트러블 슈팅
- 3 minsQuerydsl Projections 사용시 발생한 문제 해결 과정
프로젝트 진행 중 발생한 오류에 관해 기록했습니다.
QueryDsl에서 Projections.bean() 사용 시 발생하는 ExpressionException 일으킨 기존 코드
package com.WalkiePaw.domain.chatroom.repository;
import com.WalkiePaw.presentation.domain.chatroom.dto.ChatroomListResponse;
import com.querydsl.core.types.Projections;
import com.querydsl.jpa.impl.JPAQueryFactory;
import lombok.RequiredArgsConstructor;
import org.springframework.stereotype.Repository;
import java.util.List;
import static com.WalkiePaw.domain.chatroom.entity.QChatroom.*;
@Repository
@RequiredArgsConstructor
public class ChatroomRepositoryOverrideImpl implements ChatroomRepositoryOverride {
private final JPAQueryFactory jpaQueryFactory;
@Override
public List<ChatroomListResponse> findByMemberId(final Integer memberId) {
return jpaQueryFactory
.select(Projections.fields(ChatroomListResponse.class,
chatroom.id, chatroom.board.location, chatroom.member.nickname
, chatroom.latestMessage, chatroom.unreadCount
))
.from(chatroom)
.where(chatroom.board.id.eq(memberId).or(chatroom.member.id.eq(memberId)))
.fetch();
}
}
에러 발생
Projections.bean()은 기본 생성자와 setter를 기반으로 동작한다, 그래서 해당 DTO에 기본생성자가 없으면 에러가 발생!!!
또한 setter가 없다면 DTO의 필드에 값이 할당되지 못해서 모든 필드가 null이 되므로 주의해야한다.
오류 해결 전 ChatroomListResponse 코드
package com.WalkiePaw.presentation.domain.chatroom.dto;
import com.WalkiePaw.domain.chatroom.entity.Chatroom;
import lombok.AllArgsConstructor;
import lombok.Data;
@Data
@AllArgsConstructor
public class ChatroomListResponse {
private final Integer id;
private final String location;
private final String nickname;
private final String latestMessage;
private final int unreadCount;
public static ChatroomListResponse from(final Chatroom chatroom) {
return new ChatroomListResponse(chatroom.getId(), chatroom.getBoard().getLocation(),
chatroom.getMember().getNickname(), chatroom.getLatestMessage(), chatroom.getUnreadCount());
}
}
오류 해결 후 ChatroomListResponse 코드 🧏🏻♀️
package com.WalkiePaw.presentation.domain.chatroom.dto;
import com.WalkiePaw.domain.chatroom.entity.Chatroom;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@AllArgsConstructor
@NoArgsConstructor
public class ChatroomListResponse {
private Integer id;
private String location;
private String nickname;
private String latestMessage;
private int unreadCount;
public static ChatroomListResponse from(final Chatroom chatroom) {
return new ChatroomListResponse(chatroom.getId(), chatroom.getBoard().getLocation(),
chatroom.getMember().getNickname(), chatroom.getLatestMessage(), chatroom.getUnreadCount());
}
}