Vfrdtyky

Update: the following is using Spring Boot 2.1.0

I have a Spring Data repository and I am trying to provide some custom functionality to it, following the fragments example from the documentation.

So I've added an extra interface to the repository:

public interface UserRepository extends JpaRepository<User, Long>, UserExtraLogic {

    User findByFirstNameAndLastName(String firstName, String lastName);

}

with this custom interface:

interface UserExtraLogic {

    void ensureHasAccess();

}

and its implementation:

class UserExtraLogicImpl implements UserExtraLogic {

    public void ensureHasAccess() {

    }

}

The problem is that I would like to be able to use my repositories inside UserExtraLogicImpl, so that I can reuse query methods like findByFirstNameAndLastName without having to write them by myself with EntityManager. So I tried this:

class UserExrtaLogicImpl implements UserExtraLogic {

    @Autowired

    private UserRepository userRepository;

}

But then the application does not start. I get a NullPointerException, but I think it's just Spring getting into a cycle trying to resolve these dependencies.

Is what I'm trying to do possible? Is there another way to do this?

Repositories enablement

From documentation

If you're using Spring XML configuration, you should have this:

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

  xmlns:jpa="http://www.springframework.org/schema/data/jpa"

  xsi:schemaLocation="http://www.springframework.org/schema/beans

    http://www.springframework.org/schema/beans/spring-beans.xsd

    http://www.springframework.org/schema/data/jpa

    http://www.springframework.org/schema/data/jpa/spring-jpa.xsd">



  <jpa:repositories base-package="com.acme.repositories" />



</beans>

If you're using Java configuration instead, you should have this:

@Configuration

@EnableJpaRepositories("com.acme.repositories")

class ApplicationConfiguration {



  @Bean

  EntityManagerFactory entityManagerFactory() {

    // …

  }

}

Repositories configuration

Also, you need to add @Repository annotation on your repositories:

@Repository

public interface UserRepository extends JpaRepository<User, Long>, UserExtraLogic {

    User findByFirstNameAndLastName(String firstName, String lastName);

}

Explanation

From documentation

Using the repositories element looks up Spring Data repositories as
described in “Creating Repository Instances”. Beyond that, it
activates persistence exception translation for all beans annotated
with @Repository, to let exceptions being thrown by the JPA
persistence providers be converted into Spring’s DataAccessException
hierarchy.