如何在JPA存储库中使用自定义方法中的规范

@Entity
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String name;
    private String email;
    // getters and setters
}

public interface UserRepository extends JpaRepository<User, Long>, JpaSpecificationExecutor<User> {
}

public class UserSpecifications {

    public static Specification<User> hasName(String name) {
        return (root, query, criteriaBuilder) -> criteriaBuilder.equal(root.get("name"), name);
    }

    public static Specification<User> hasEmail(String email) {
        return (root, query, criteriaBuilder) -> criteriaBuilder.equal(root.get("email"), email);
    }
}

@Service
public class UserService {

    private final UserRepository userRepository;

    public UserService(UserRepository userRepository) {
        this.userRepository = userRepository;
    }

    public List<User> findUsersByNameAndEmail(String name, String email) {
        Specification<User> spec = Specification.where(UserSpecifications.hasName(name))
                                                  .and(UserSpecifications.hasEmail(email));
        return userRepository.findAll(spec);
    }
}