QueryDSL(2)

이 글은  QueryDSL의 2가지 방법 중 2번째 방법이다. 사용자 정의 인터페이스 설계 후 QueryDslRepositorySupport 상속받는 것이다.

 

1. pom.xml에 querydsl dependency  추가(이전 글 참고)

 

2. 사용자 정의 인터페이스 설계

package com.example.mart.repository;

import com.example.mart.entity.Item;

import com.example.mart.entity.Member;

import java.util.List;

public interface QueryDslOrderRepository {

  public List<Object[]> joinList();

  public List<Member> members();

  public List<Item> items();

}

 

3. 사용자 정의 인터페이스를 구현하는 클래스 작성

package com.example.mart.repository;

import com.example.mart.entity.Item;

import com.example.mart.entity.Member;

import com.example.mart.entity.Order;

import com.example.mart.entity.QItem;

import com.example.mart.entity.QMember;

import com.example.mart.entity.QOrder;

import com.example.mart.entity.QOrderItem;

import com.querydsl.core.Tuple;

import com.querydsl.jpa.JPQLQuery;

import java.util.List;

import java.util.stream.Collectors;

import org.springframework.data.jpa.repository.support.QuerydslRepositorySupport;

public class QueryDslOrderRepositoryImpl

  extends QuerydslRepositorySupport

  implements QueryDslOrderRepository {

  public QueryDslOrderRepositoryImpl() {

    super(Order.class);

  }

  @Override

  public List<Object[]> joinList() {

    QMember member = QMember.member;

    QOrder order = QOrder.order;

    QOrderItem orderItem = QOrderItem.orderItem;

    JPQLQuery<Order> query = from(order);

    query.join(order.member, member).leftJoin(order.orderItems, orderItem);

    JPQLQuery<Tuple> tuple = query.select(member, order, orderItem);

    List<Tuple> result = tuple.fetch();

    List<Object[]> list = result

      .stream()

      .map(t -> t.toArray())

      .collect(Collectors.toList());

    return list;

  }

  @Override

  public List<Member> members() {

    // select * from member where name = 'user1' order by name desc

    QMember member = QMember.member;

    JPQLQuery<Member> query = from(member);

    query.where(member.name.eq("user1")).orderBy(member.name.desc());

    JPQLQuery<Member> tuple = query.select(member);

    List<Member> list = tuple.fetch();

    return list;

  }

  @Override

  public List<Item> items() {

    // select * from item where name='바지' and price>20000

    QItem item = QItem.item;

    JPQLQuery<Item> query = from(item);

    query.where(item.name.eq("바지").and(item.price.gt(20000)));

    JPQLQuery<Item> tuple = query.select(item);

    List<Item> list = tuple.fetch();

    return list;

  }

}