如何在服务和存储库中使用@Qualifier

Question

I have a generic repository interface called UserRepository. I then have an interface which extends from that called MyUserRepository. It deals with an MyUser class which extends User.

I also have a Service Interface called UserService and a class called MyUserServiceImpl.

The service wants an instance of the UserRepository and I though I could use some sort of annotation like @Qualifier but it doesn't work.

@NoRepositoryBean
public interface UserRepository <T extends User> extends JpaRepository<T, Long>{
    <S extends T> S findByLoginName(String loginName);

    <S extends T> S saveAndFlush(User user);
}

@Repository
@Qualifier("myUserRepository")
public interface MyUserRepository extends UserRepository<MyUser> {

}


public interface UserService {

    public List<User> getUsers();
}

@Service
public class MyUserServiceImpl implements UserService {

    @Autowired
    @Qualifier("myUserRepository")
    private UserRepository<User> userRepository;

    @Override
    public List<User> getUsers() {
....
    }

}

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APPLICATION FAILED TO START

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Description:

Parameter 0 of constructor in com....services.MyUserServiceImpl required a bean of type 'com....repositories.UserRepository' that could not be found.

The injection point has the following annotations: - @org.springframework.beans.factory.annotation.Autowired(required=true)

Action:

Consider defining a bean of type 'com....repositories.UserRepository' in your configuration.

Answer 1

@Qualifier annotation is used only when calling a bean already created. So you shouldn't call on class head, you might name it @Repository("myUserRepository") and call it on after @Autowired @Qualifier("myUserRepository")

Answer 2

No need to have a qualifier in your case.

@Repository
public interface MyUserRepository extends UserRepository<MyUser> {

}

Auto-wire the repository as :

@Service
public class MyUserServiceImpl implements UserService {

    @Autowired
    private UserRepository<User> userRepository;

    ...

Answer 3

@Qualifier is used with @Autowired annotation. By default @Autowired will inject beans based on types.When you have multiple beans of same types then @Qualifier helps to resolve the conflict. In your case using annotation @Repository will do you job. Also in your UserRepository interface , you have to supply the Id class along with JPA entity class.