<bean id="xxx.scheduler"
        class="org.springframework.scheduling.quartz.SchedulerFactoryBean">
</bean>

@Component
public class QuartzScheduler {
  @Qualifier("xxx.scheduler")
  @Autowired
  Scheduler scheduler;

  @PostConstruct
  public void start() {
    try {
      scheduler.start();
    } catch (SchedulerException e) {
      log.error("", e);
    }
  }

}

定義的時候定義了SchedulerFactoryBean的id為"xxx.scheduler"，為什么注入Scheduler的時候也可以用這個ID注入？？？