Question

我有一个Spring ApplicationListener的实现。它工作正常并在上下文xml文件中声明为bean时或者如果我使用@Component注释时接收事件。

但是，如果我使用ConfigurableListableBeanFactory的{{1}}方法手动注册代码，则不会收到事件。

我在下面添加了一些描述工作而非工作案例的示例代码。

CustomEvent.java

registerSingleton()

CustomEventPublisher.java

package com.test.event;

import org.springframework.context.ApplicationEvent;

public class CustomEvent extends ApplicationEvent {

    public CustomEvent(Object source) {
        super(source);
    }

    public String toString() {
        return "My Custom Event";
    }
}

CustomEventHandler.java

package com.test.event;

import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.ApplicationEventPublisherAware;

public class CustomEventPublisher implements ApplicationEventPublisherAware {

    private ApplicationEventPublisher publisher;

    public void setApplicationEventPublisher(ApplicationEventPublisher publisher) {
        this.publisher = publisher;
    }

    public void publish() {
        CustomEvent ce = new CustomEvent(this);
        publisher.publishEvent(ce);
    }
}

applicationContextWithListenerBean.xml

package com.test.event;

import org.springframework.context.ApplicationListener;

public class CustomEventHandler 
   implements ApplicationListener<CustomEvent>{

   public void onApplicationEvent(CustomEvent event) {
      System.out.println(event.toString());
   }

}

applicationContextWithoutListenerBean.xml

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

   <bean id="customEventHandler" 
      class="com.test.event.CustomEventHandler"/>

   <bean id="customEventPublisher" 
      class="com.test.event.CustomEventPublisher"/>

</beans>

MainApp.java

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

   <bean id="customEventPublisher" 
      class="com.test.event.CustomEventPublisher"/>

</beans>

是否无法通过代码注册package com.test.event; import org.springframework.context.ConfigurableApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; public class MainApp { public static void main(String[] args){ /* The below code works fine when listener bean customEventHandler is defined in xml */ ConfigurableApplicationContext context = new ClassPathXmlApplicationContext( "applicationContextWithListenerBean.xml"); CustomEventPublisher cvp = (CustomEventPublisher) context .getBean("customEventPublisher"); cvp.publish(); context.close(); /* The below code doesn't work when listener bean is registered through code. Is it possible to make this work? */ ConfigurableApplicationContext context = new ClassPathXmlApplicationContext( "applicationContextWithoutListenerBean.xml"); context.getBeanFactory().registerSingleton("customEventHandler", new CustomEventHandler()); CustomEventPublisher cvp = (CustomEventPublisher) context .getBean("customEventPublisher"); cvp.publish(); context.close(); } }？

Answer 1

将bean注册为单例将无法在ApplicationEvents上调用它。

context.addApplicationListener(new CustomEventHandler());

应改为

*.jsm

这会将ApplicationListener实现添加到ApplicationEventMulticaster，将事件发布到ApplicationListeners

如何通过代码注册Spring ApplicationListener实现？

1 个答案: