范围内的春季活动是否可能?

医生:我想它已经按你想要的方式工作了。

长版本:

文档对此有些不清楚,但尝试了一个简单的测试:

发布事件的控制器:

@Controller
public class FooController {
    @Autowired
    private ApplicationEventPublisher publisher;

    @GetMapping("/fireEvent")
    public void fireEvent() {
        publisher.publishEvent(new FooEvent(this));
    }
}

还有一个听的有范围的豆子:

@Scope(value = WebApplicationContext.SCOPE_REQUEST)
@Component
public class FooListener {
    @EventListener(FooEvent.class)
    public void listen() {
         System.out.println("I'm listening. PS : I am "+this.toString());
    }
}

当运行两个并发请求时,只有作用于同一个httpRequest的侦听器才能获取事件。

我的解释 (不必看得很深,就拿一粒盐吃吧):

在我看来 ApplicationEventMulticaster 的 ListenerRetriever 使用BeanFactory获取以前注册为侦听器的bean(通过它们的名称)。显然,工厂将返回当前范围内的bean。

请查看这是否是您要查找的内容:

主要用途:

   package com.fg7.evision.EventList;

    import org.springframework.context.annotation.AnnotationConfigApplicationContext;
    import org.springframework.context.annotation.ComponentScan;

    @ComponentScan(basePackages = "com.fg7.evision.EventList")
    public class EventApplication {


        public static void main(String[] args) {
           MyScopedEvent event = new MyScopedEvent("hello world");
           AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(EventApplication.class);
            ctx.publishEvent(event);
        }

    }

事件:

 package com.fg7.evision.EventList;

    public class MyScopedEvent  {

        private String message;

        public MyScopedEvent( String message) {
            this.message = message;
        }

        public String getMessage() {
            return message;
        }
    }

事件侦听器的作用域仅限于单例作用域。

package com.fg7.evision.EventList;

import org.springframework.beans.factory.BeanNameAware;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.event.EventListener;
import org.springframework.stereotype.Component;

@Component(value = "listener")
public class ScopedEventListener implements BeanNameAware {

    @Autowired
    ConfigurableApplicationContext context;

    String beanName;

    @Override
    public void setBeanName(String name) {
        this.beanName = name;
    }

    @EventListener(condition = "@listener.getScope() == 'singleton'")
    public void handleEvent(MyScopedEvent myScopedEvent) {
        System.out.println(myScopedEvent.getMessage());

    }

    public String getScope(){
        return this.context.getBeanFactory().getBeanDefinition(this.beanName).getScope();
    }


}