dubbo-client启动报错

Exception in thread "main" java.lang.NullPointerException at org.spring.springboot.dubbo.CityDubboConsumerService.printCity(CityDubboConsumerService.java:20) at org.spring.springboot.ClientApplication.main(ClientApplication.java:22)

为什么这个springboot项目 启动就会直接调用CityDubboConsumerService的方法

/**

• 城市 Dubbo 服务消费者

• Created by bysocket on 28/02/2017. */ @Component public class CityDubboConsumerService {

  @Reference(version = "1.0.0") CityDubboService cityDubboService;

  public void printCity() { String cityName="温岭"; City city = cityDubboService.findCityByName(cityName); // 这行启动就报空指针 System.out.println(city.toString()); } }