如何使用springdata和mongodb搜索小于所需的日期？

@Repository
public interface UserRepository extends MongoRepository<User, String> {
}

@Repository
public interface UserRepository extends MongoRepository<User, String> {
    List<User> findByBirthdateLessThan(Date date);
}

@Service
public class UserService {
    @Autowired
    private UserRepository userRepository;

    public List<User> searchUsersByBirthdate(Date date) {
        return userRepository.findByBirthdateLessThan(date);
    }
}