Spring Data JPA无法找到具有给定名称的Attribute

我试图用Spring Data JPA在Spring Boot和我一直得到错误，我想不通的问题是什么：

FirstName在我的实体类中声明。之前我在其他项目中使用过DAO的服务类，并且运行良好。

我的Entity类（getter和setter也在该类中）：

        @Entity
        public class Subscriber {

        @Id @GeneratedValue
        private long id;
        private String FirstName,LastName,Email;

        public Subscriber(long id,String firstName,String lastName,String email) {
            this.id = id;
            this.FirstName = firstName;
            this.LastName = lastName;
            this.Email = email;
          }
        }
...

我的存储库类

@Component
public interface SubscriberRepository extends JpaRepository<Subscriber,Long> {
    Subscriber findByFirstName(String FirstName);
    Subscriber deleteAllByFirstName(String FirstName);
}

我的服务等级

@service
public class Subscriberservice {

    @Autowired
    private SubscriberRepository subscriberRepository;

    public Subscriber findByFirstName(String Name){
        return  subscriberRepository.findByFirstName(Name);

    }

    public Subscriber deleteAllByFirstName(String Name){
        return  subscriberRepository.deleteAllByFirstName(Name);

    }

    public void addSubscriber(Subscriber student) {
        subscriberRepository.save(student);
    }
}

和我的控制器类：

@RestController
@requestMapping("/subscribers")
public class SubscriberController {

    @Autowired
    private Subscriberservice subscriberservice;

    @GetMapping(value = "/{name}")
    public Subscriber findByFirstName(@PathVariable("name") String fName){
        return  subscriberservice.findByFirstName(fName);
    }

    @PostMapping( value = "/add")
    public String insertstudent(@requestBody final Subscriber subscriber){
        subscriberservice.addSubscriber(subscriber);
        return "Done";
    }

}