Custom annotation is not working on spring Beans

问题

I have created my new custom annotation @MyCustomAnnotation

@Target({ElementType.METHOD, ElementType.TYPE, ElementType.FIELD})
@Retention(RUNTIME)
public @interface MyCustomAnnotation{
}

I applied that annotation on component and bean. Here is the code,

@MyCustomAnnotation
@Component
public class CoreBussinessLogicHandler implements GenericHandler<BussinessFile> {
//some bussiness logic
}

And

@Configuration
public class BussinessConfig {

    @Autowired
    private CoreIntegrationComponent coreIntegrationComponent;

    @MyCustomAnnotation
    @Bean(name = INCOMING_PROCESS_CHANNEL)
    public MessageChannel incomingProcessChannel() {
        return coreIntegrationComponent.amqpChannel(INCOMING_PROCESS_CHANNEL);
    }

    //some other configurations
}

Now i want all the beans annotated with @MyCustomAnnotation. So here is the code,

import org.springframework.context.ApplicationContext;

@Configuration
public class ChannelConfig {

      @Autowired
      private ApplicationContext applicationContext;

      public List<MessageChannel> getRecipientChannel(CoreIntegrationComponent coreIntegrationComponent) {

      String[] beanNamesForAnnotation = applicationContext.getBeanNamesForAnnotation(MyCustomAnnotation.class);
      //Here in output I am getting bean name for CoreBussinessLogicHandler Only.

    }
}

My question is why I am not getting Bean with name 'INCOMING_PROCESS_CHANNEL' as it has @MyCustomAnnotation ? If I want to get bean with name 'INCOMING_PROCESS_CHANNEL' what code changes should I do ?

回答1:

This happens because your bean does not receive this annotation as you have placed it on a "bean definition configuration". So it is available but only through BeanFactory and beanDefinitions. You can either put the annotation on your bean class or write a custom method that would do the searching using bean factory.

See the accepted answer here.

回答2:

You have to use AnnotationConfigApplicationContext instead of ApplicationContext

Here is a working example:

@SpringBootApplication
@Configuration
public class DemoApplication {

    @Autowired
    public AnnotationConfigApplicationContext ctx;

    @Bean
    public CommandLineRunner CommandLineRunner() {
        return (args) -> {
            Stream.of(ctx.getBeanNamesForAnnotation(MyCustomAnnotation.class))
                    .map(data -> "Found Bean with name : " + data)
                    .forEach(System.out::println);
        };
    }

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

@Target({ElementType.METHOD, ElementType.TYPE, ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
@interface MyCustomAnnotation{
}

@MyCustomAnnotation
@Component
class Mycomponent {
    public String str = "MyComponentString";
}

来源：https://stackoverflow.com/questions/45931541/custom-annotation-is-not-working-on-spring-beans