在SpringBoot中获取某个注解标记的`BeanName`

1. 要查找的类的范围必须是Spring Bean的实例。
2. 实现ApplicationListener<ContextRefreshedEvent>接口，实现其方法。

 @Override    public void onApplicationEvent(ContextRefreshedEvent event) {        Map<String, Object> beans = event.getApplicationContext().getBeansWithAnnotation(CrawlUrl.class);//实例名，该实例        String[] beanNamesForAnnotation = event.getApplicationContext().getBeanNamesForAnnotation(CrawlUrl.class);//实例    }