15장 프로젝션과 결과 반환 - @QueryProjection

1) 생성자 + @QueryProjection

MemberDto.java

package study.querydsl.dto;
import com.querydsl.core.annotations.QueryProjection;
import lombok.Data;
@Data
public class MemberDto {
 private String username;
 private int age;
 public MemberDto() {
 }
 @QueryProjection
 public MemberDto(String username, int age) {
 this.username = username;
 this.age = age;
 }
}

- ./gradlew compileQuerydsl

- QMemberDto 생성 확인

 

2) @QueryProjection 활용

List<MemberDto> result = queryFactory
 .select(new QMemberDto(member.username, member.age))
 .from(member)
 .fetch();