在回收中使用集合（集合）的休眠条件

Question

I have a Pojo class like below.

public class Book{

  @Id
  @Column(name = "ID", unique = true, nullable = false)
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  long id;

  @Column(name = "NAME", nullable = false)
  String name;

  @OneToOne
  @JoinColumn(name = "PERSON_ID", nullable = false)
  Person owner;
}

I have Set of persons(owner) like Set owners. Now I want to fetch all the books of owners (Set). How can I add this condition in Hibernate criteria. I don't want to use HQL.

Answer 1

I think you need to use Restrictions.in like so :

Criteria criteria = session.createCriteria(Book.class)
                    .add(Restrictions.in("owner", 
                               new Person[] {person1, person2, person1}));

List<Book> resultList = criteria.list();

Also I think it is possible to use :

Criteria criteria = session.createCriteria(Book.class)
                        .add(Restrictions.in("owner", 
                                new HashSet<>(Arrays.asList(person1, person2, person1))));

Answer 2

Well with Criteria you can use Restrictions.in() method like this:

List<Book> books = session.createCriteria(Book.class)
    .createAlias("owner", "o")
    .add(Restrictions.in("o", ownersCollection.toArray(new Book[ownersCollection.size()])))
    .list();

Where ownersCollection is your collection of owners, in this code I used ownersCollection as a List<Book> but it will also work perfectly with Set<Book> .

Note that .equals() should be correctly implemented in your Owner class in order to get correct results.

For further reading about it you can check:

• Hibernate Criteria Queries tutorial .
• How do I use Hibernate's Restriction.in criterion? .