Spring dynamic JPA repository type

Question

I have about 30 tables that I need to fill from an XML file. And I want to use JPA for that purpose.

Now I have 30 classes annotated with @Entity, config that scans entities and repositories;

Also I have:

@Repository
public interface MyRepository extends JpaRepository<MyEntity1, Long> {
}

And (some controller):

@Autowired
public MyRepository myRepository;
...
...
MyEntity1 entity = new MyEntity(...);
myRepository.save(entity);

It works fine with one @Entity but should I define 30 repositories for that?

I thought I could do something like this:

@Repository
public interface MyRepository<T> extends JpaRepository<T, Long> {
}

and then:

@Autowired
public MyRepository<MyEntity1> myRepository1;
@Autowired
public MyRepository<MyEntity2> myRepository2;

but that gave an error:

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'myRepository1': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Not a managed type: class java.lang.Object

Don't forget to accept/upvote answers that helped you... – Cepr0 Dec 25 '17 at 09:21 — Cepr0, Dec 25 '17 at 09:21

score 4 · Answer 1 · answered Jul 19 '17 at 11:36

Try this approach:

Base class for all entities:

@Entity
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
public abstract class BaseEntity {

    @Id
    @GeneratedValue(strategy = GenerationType.TABLE)
    private Long id;
}

Entities:

@Entity
public class Entity1 extends BaseEntity {

    private String name;
}

@Entity
public class Entity2 extends BaseEntity {

    private String name;
}

A common repo:

public interface BaseEntityRepo extends JpaRepository<BaseEntity, Long> {
}

Usage:

public class BaseEntityRepoTest extends BaseTest {

    @Autowired
    private BaseEntityRepo repo;

    @Test
    public void baseEntityTest() throws Exception {

        BaseEntity entity1 = new Entity1("entity1");
        BaseEntity entity2 = new Entity2("entity2");

        repo.save(entity1);
        repo.save(entity2);

        List<BaseEntity> entities = repo.findAll();
        assertThat(entities).hasSize(2);

        entities.forEach(System.out::println);
    }
}

will this work for mongo db as well ? – chaitanya Jul 04 '23 at 10:56 — chaitanya, Jul 04 '23 at 10:56

score 3 · Answer 2 · answered Jul 19 '17 at 09:39

Unfortunately you can't do this and you will have to write 30 separate repositories. You can however write generic repositories when the entities share a single table inheritance. (See the answer to Using generics in Spring Data JPA repositories)

What your code is trying to do is make a repository where the shared inheritance is on the class Object which isn't an @Entity hence the exception.

Also an additional minor note, you don't need to annotate your repositories with @Repository. Spring data automatically registers these as beans if it is configured correctly.

Thanks. I added `@Repository` annotation when I tried to fix that I wasn't able to autowire repository, but error was that I misspelled package with repos to scan =). Anyway, you cleared my mind, thanks) — Frankie Drake, Jul 19 '17 at 09:42

score 2 · Answer 3 · answered Jul 19 '17 at 09:36

2

As far as I am aware what you are trying is not possible. Spring Data JPA needs an interface per Entity type for its repositories, Because Spring Data JPA will be creating the query implementations.

So it is advised that you have a Repository per Entity as it will allow you to add complex findByXXX methods in the future also.

answered Jul 19 '17 at 09:36

shazin

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Thank you, I'm going to get a lot copy-paste work ;) – Frankie Drake Jul 19 '17 at 09:42

Spring dynamic JPA repository type

3 Answers3