如何在QueryDSL中为多对多关系创建谓词BooleanExpression

Question

public class A {

  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  private Integer id;

 @ManyToMany(fetch = FetchType.LAZY,
  cascade = { CascadeType.DETACH, CascadeType.MERGE, 
      CascadeType.REFRESH, CascadeType.PERSIST})
  @JoinTable(name = "a_b_maps",
      joinColumns = @JoinColumn(name = "a_id", nullable = 
          false,referencedColumnName = "id"),
      inverseJoinColumns = @JoinColumn(name = "b_id", nullable = false, 
        referencedColumnName = "id")
  )
  private Set<B> listOfB = new HashSet<B>();
}


public class B {

  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  private Integer id;

 @ManyToMany(fetch = FetchType.LAZY,
  cascade = { CascadeType.DETACH, CascadeType.MERGE, 
      CascadeType.REFRESH, CascadeType.PERSIST})
  @JoinTable(name = "a_b_maps",
      joinColumns = @JoinColumn(name = "b_id", nullable = 
          false,referencedColumnName = "id"),
      inverseJoinColumns = @JoinColumn(name = "a_id", nullable = false, 
        referencedColumnName = "id")
  )
  private Set<A> listOfA = new HashSet<A>();
}

基础回购

@NoRepositoryBean
public interface BaseRepository<E, I extends Serializable>
    extends JpaRepository<E, I> {

}

和存储库类

public interface Arepo extends BaseRepository<A, Integer>,
    QueryDslPredicateExecutor<A> {
    Page<A> findAll(Predicate predicate, Pageable pageRequest);

}

现在我想使用带有谓词查询的Repo。我需要形成一个谓词，在这个谓词中，我可以根据给定的Bs加载

QA a = QA.a;
QB b = QB.b;
BooleanExpression boolQuery = null;
JPQLQuery<A> query = new JPAQuery<A>();
  query.from(a).innerJoin(a.listOfB, b)
    .where(b.id.in(someList));

Answer 1

我能够在这里给出的答案的帮助下创建一个谓词

https://stackoverflow.com/A/23092294/1969412。

因此，我不使用jpqlquery，而是直接使用

a.listOfB.any()
      .id.in(list);