java - spring 4.2 应用程序事件使用 Spring MVC 触发两次，为什么？

Question

我正在使用 Spring 4.2.0.BUILD-SNAPSHOT events ，出于某种我还没有弄清楚的原因，监听器在发布任何事件后触发两次，无论是从 ApplicationEvent 扩展还是任何任意事件，但是在运行测试用例时一切都按预期工作，现在想知道注释是怎么回事Spring MVC 上下文中的驱动事件

事件发布接口(interface)

public interface ListingRegistrationService {
    public void registerListing(ListingResource listing);

}

@Component
class ListingRegistrationServiceImpl implements ListingRegistrationService{

    private final ApplicationEventPublisher publisher;

    @Autowired
    public ListingRegistrationServiceImpl(ApplicationEventPublisher publisher) {
        this.publisher = publisher;
    }

    @Override
    public void registerListing(ListingResource listing) {
       //process
        publisher.publishEvent(new ListingCreatedEvent(listing));
        System.out.println("Event above...");
    }

}

事件监听器

@EventListener
    @Async
    public void sendMailForSuggestedListing(Supplier<ListingResource> listingCreatedEvent)  {
        System.out.println("Event fired...");
    }

终点/入口点

public ResponseEntity<ResponseStatus> registerListing(@RequestBody @Valid ListingResource listing,BindingResult result) throws URISyntaxException {
       ResponseEntity<ResponseStatus> response = null;
       listingService.registerListing(listing); //  publish the event
       response = ResponseEntity.created(new URI(""));
         return response;
            }

结果:事件被解雇...事件被解雇...上面的事件..

I suspect indeed that the EventListener bean is registered twice or something. You can enable org.springframework.context.event.EventListenerMethodProcessor to trace level to check what happens to this particular class.

——史蒂芬·尼科尔

追踪org.springframework.context.event.EventListenerMethodProcessor一切都发生两次

12:02:32,878 DEBUG ntext.event.EventListenerMethodProcessor: 138 - 1 @EventListener methods processed on bean 'mailServiceImpl': [public void com.service.MailServiceImpl.sendMailForSuggestedListing(com.service.events.CreationEvent)]
12:02:32,878 DEBUG ntext.event.EventListenerMethodProcessor: 138 - 1 @EventListener methods processed on bean 'mailServiceImpl': [public void com.service.MailServiceImpl.sendMailForSuggestedListing(com.service.events.CreationEvent)]
12:02:32,878 TRACE ntext.event.EventListenerMethodProcessor: 132 - No @EventListener annotations found on bean class: class com.service.MetaServiceImpl
12:02:32,878 TRACE ntext.event.EventListenerMethodProcessor: 132 - No @EventListener annotations found on bean class: class com.service.MetaServiceImpl

Java configuration

@Configuration
@ComponentScan(basePackages = {"com.**.domain",
        "com.**.repositories", "com.**.service",
        "com.**.security" })
@PropertySource(value = { "classpath:application.properties" })
public class ServiceConfig 


Configuration
@EnableWebMvc
@EnableSwagger
@EnableSpringDataWebSupport
@EnableMongoRepositories("com.**.repositories")
@ComponentScan(basePackages = {"com.**.config","com.**.rest.controllers","com.**.rest.tokens"})
public class WebConfig extends WebMvcConfigurerAdapter {

@Configuration
@EnableMongoRepositories("com.**.**.repositories")
public class MongoRepositoryConfig extends AbstractMongoConfiguration

Answer 1

我遇到了同样的问题。对我来说...我注册了两次事件监听器，因为我在一个配置类中全面扫描了我的整个包路径

@ComponentScan(  basePackages = {"my.root.package"} )
@Configuration
public class MyAppConfig {
      //... 
}

然后我像这样在另一个配置类中手动添加了相同的 eventListener bean

@Configuration
public class SpringConfig {
    ...
    // SomeEventListener was located @ my.root.package.event and had @Component annotation
    @Bean 
    public SomeEventListener someEventListener() {
        return new SomeEventListener();
    }
    ...
}

导致它注册两次。