Spring Boot extending CrudRepository

Question

I'm using Hibernate in a Spring Boot app. I'm making a new CrudRepository for all my Model objects, to do basic CRUD tasks. They look like this:

@Repository
public interface FoobarCrudRepo extends CrudRepository<Foobar, Long> {
}

But then I always need to do some additional things, like custom search queries with inequalities and such. I follow a pattern like this:

@Repository
public class FoobarDao {

    @PersistenceContext
    EntityManager em;

    public List<Foobar> findFoobarsByDate(Date date) {
        String sql = "select fb from Foobar fb where createdDate > :date";
        ...
        return query.getResultList();
    }
}

My question is, can I combine these two concepts into a single class? I tried making it an abstract class, like so:

@Repository
public abstract class FoobarCrudRepo extends CrudRepository<Foobar, Long> {

    @PersistenceContext
    EntityManager em;

    public List<Foobar> findFoobarsByDate(Date date) {
        String sql = "select fb from Foobar fb where createdDate > :date";
        ...
        return query.getResultList();
    }

}

But then Spring didn't create a bean for it.

How can I accomplish this?

Thanks!

Answer 1

There are lots of ways you could probably accomplish this. If you really need absolute control try this

interface FoobarRepositoryCustom{
    List<Foobar> findFoobarsByDate(Date date);
}

interface FoobarRepository extends CrudRepository<Foobar, Long>, FoobarRepositoryCustom

public class FoobarRespoitoryImpl implements FoobarRepositoryCustom{
    @PersistenceContext private EntityManager em;


    public List<Foobar> findFoobarsByDate(Date date) {
    String sql = "select fb from Foobar fb where createdDate > :date";
    ...
    return query.getResultList();
    }
}

There is also the possibility to go a simpler route and the query can be auto generated for you based on the method name. In your example you could just add this to your FoobarCrudRepo and Spring should do the rest assuming Foobar has a property named CreatedDate

List<Foobar> findByCreatedDateGreaterThan(Date date);

For reference on how Spring can generate queries based on the method name see this http://docs.spring.io/spring-data/jpa/docs/current/reference/html/#repositories.query-methods.query-creation

Answer 2

The problem here is abstract keyword.

@Repository
public abstract class FoobarCrudRepo extends CrudRepository<Foobar, Long>

Spring will not create a bean for a class unless it is a concrete class. That's why you are getting a bean for it.

Answer 3

This is what worked for me...

@SpringBootApplication(scanBasePackages = { "com.myproject" })
@EnableJpaRepositories(basePackages="com.myproject.sprinbootapp.repository")
    @EntityScan("com.myproject.sprinbootapp.model")
    public class SpringbootAppWithDatabaseApplication {

        public static void main(String[] args) {
            SpringApplication.run(SpringbootAppWithDatabaseApplication.class, args);
        }
    }

@Service
public class TopicService {

    @Autowired
    private TopicRepository topicRepository;

    private List<Topics> topics = new ArrayList<Topics>();

    public List<Topics> getAllTopics(){
        List<Topics> listOfTopics = new ArrayList<Topics>();
        topicRepository.findAll().forEach(listOfTopics::add);;
        return listOfTopics;
    }

}

@Entity
public class Topics {

    @Id
    private String id;

    private String name;

    public Topics(){

    }
 getters and setters...
}

public interface TopicRepository extends CrudRepository<Topics, String> {

}

Answer 4

we can use the JPA EntityManager for direct sql actions:

public interface VerificationsRepository extends
    CrudRepository<Verification, Integer>,
    DAOAccess
{ }

interface DAOAccess {
   List findByEmail(String email);

}

class DAOAccessImpl implements DAOAccess {
   @PersistenceContext private EntityManager em;

    public List findByEmail(String email) {
        String sql =
            "select * from verifications where email = ?";
        Query query = em.createNativeQuery(sql, Verification.class)
            .setParameter(1, email);
        return query.getResultList();
    }
}