How to force eager loading with CrudRepository in spring-data?

Question

I have an entity containing a List that is thus lazy loaded by default:

interface MyEntityRepository extends CrudRepository<MyEntity, Long> {

}

@Entity
public class MyEntity {
    @Id
    private Long id;

    @OneToMany(mappedBy = "bar") //lazy by default
    private List<Bar> bars;
}

@Entity
public class Bar {
    //some more
}

Question: How can I force eager loading when executing repository.findOne(id)?

I know I can force the `eager` mode like this. But I want to stick to the `lazy` default and just force eager on all lists on one specific select. — membersound, Aug 06 '15 at 12:02
Well then, If you're using criteria in DAO you can force fetch type by `criteria.setFetchMode("bars", FetchMode.EAGER)` — Jebil, Aug 06 '15 at 12:05
or you can use `MyEntity p = (MyEntity) sess.get(MyEntity.class, id); Hibernate.initialize(p.getBars());` — Jebil, Aug 06 '15 at 12:11
So that would imply writing my own criterea. Which is fine in general, but I hope spring-data would bring something for this. — membersound, Aug 06 '15 at 12:29
you can write a query @Query("select m from MyEntity m LEFT JOIN FETCH m.bars") MyEntity findOne(Long id); — Rafael Zeffa, Aug 06 '15 at 12:29

Tomasz Fijałkowski · Answer 1 · 2017-03-28T12:25:08.950

20

You can force eager fetch writing custom HQL query with left join fetch, eg:

interface MyEntityRepository extends CrudRepository<MyEntity, Long> {
    @Query("select e from MyEntity e left join fetch e.bar b where e.id = ?1")
    MyEntity findOne(long id)
}

edited Mar 28 '17 at 12:25

answered Mar 22 '17 at 13:46

Tomasz Fijałkowski

747
6
15

score 1 · Accepted Answer · edited Mar 13 '16 at 01:57

1

I needed this too and as I'm calling the dao inside a service object that is insise a transaction I call call the get method so no exception and I was able to fetch the records. Something like in java 8:

public ProductEntity findProduct(int id) {
    ProductEntity p = productRepository.findOne(id);
    p.getPresentations().stream().count();
    return p;
}

p.getPresentations().stream().count(); will force the fetch, I know is not a clean way to do it but it gets the job done in the mean time

edited Mar 13 '16 at 01:57

yedpodtrzitko

9,035
2
40
42

answered Mar 13 '16 at 01:19

Luis Rocha

50
4

9

This solution generate more then one query. – Tomasz Fijałkowski May 30 '18 at 07:31

score -9 · Answer 3 · answered Oct 24 '17 at 20:06

-9

Change your mapping from

@OneToMany(mappedBy = "bar") //lazy by default

To

@OneToMany(mappedBy = "bar", fetch = FetchType.EAGER) //lazy by default

answered Oct 24 '17 at 20:06

newbieJavaDev

1
1

3

To quote myself: "I know I can force the eager mode like this. But I want to stick to the lazy default and just force eager on [...] one specific select" – membersound Oct 25 '17 at 08:04

How to force eager loading with CrudRepository in spring-data?

3 Answers3

Linked