ProgrammingQueryDSL

QueryDSL - 동적 쿼리

목차

동적 쿼리를 해결하는 두가지 방식

  • BooleanBuilder
  • Where 다중 파라미터 사용

동적 쿼리 - BooleanBuilder

BooleanBuilder 를 이용해 동적 쿼리를 작성할 수 있다.

@Test
public void dynamicQuery_BooleanBuilder(){
    String usernameParam = "member1";
    Integer ageParam = 10;

    List<Member> result = searchMember1(usernameParam, ageParam);
    assertThat(result.size()).isEqualTo(1);
}

private List<Member> searchMember1(String usernameCond, Integer ageCond){
    BooleanBuilder builder = new BooleanBuilder();
    if(usernameCond != null){
        builder.and(member.username.eq(usernameCond));
    }

    if(ageCond != null){
        builder.and(member.age.eq(ageCond));
    }

    return queryFactory
            .selectFrom(member)
            .where(builder)
            .fetch();
}
/* select
    member1 
from
    Member member1 
where
    member1.username = ?1 
    and member1.age = ?2 */ select
        member0_.member_id as member_i1_1_,
        member0_.age as age2_1_,
        member0_.team_id as team_id4_1_,
        member0_.username as username3_1_ 
    from
        member member0_ 
    where
        member0_.username=? 
        and member0_.age=?

동적 쿼리 - Where 다중 파라미터 사용

  • 메서드를 다른 쿼리에서도 재사용 할 수 있다.
  • 쿼리 자체의 가독성이 높아진다.
@Test
public void dynamicQuery_WhereParam() {
    String usernameParam = "member1";
    Integer ageParam = 10;

    List<Member> result = searchMember2(usernameParam, ageParam);
    assertThat(result.size()).isEqualTo(1);
}

private List<Member> searchMember2(String usernameCond, Integer ageCond) {
    return queryFactory
            .selectFrom(member)
            // where 에 null 값이 전달 되면 조건을 무시한다.
            .where(usernameEq(usernameCond),
                    ageEq(ageCond))
            .fetch();
}

private Predicate usernameEq(String usernameCond) {
    // 전달받은 usernameCond 파라미터가 없을 경우 null 을 반환하도록 한다.
    if (usernameCond == null) {
        return null;
    }
    return member.username.eq(usernameCond);
}

private Predicate ageEq(Integer ageCond) {
    if (ageCond == null) {
        return null;
    }
    return member.age.eq(ageCond);
}
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