spring容器事件
spring的ApplicationContext能够发布事件并且允许注册相应的事件监听器,它拥有一套完善的事件发布和监听机制.事件体系:事件,事件监听器,事件源,事件监听器注册表,事件广播器.其中,事件源是事件的产生者,事件监听器注册表就是保存事件监听器的地方,事件广播器是事件与事件监听器沟通的桥梁,负责将事件通知给事件监听器.事件类:ApplicationEvent包含
·
spring的ApplicationContext能够发布事件并且允许注册相应的事件监听器,它拥有一套完善的事件发布和监听机制.
事件体系:事件,事件监听器,事件源,事件监听器注册表,事件广播器.其中,事件源是事件的产生者,事件监听器注册表就是保存事件监听器的地方,事件广播器是事件与事件监听器沟通的桥梁,负责将事件通知给事件监听器.
事件类:ApplicationEvent包含ApplicationContextEvent和RequestHandledEvent两个子类,容器事件ApplicationContextEvent有ContextClosedEvent,ContextRefreshedEvent,ContextStartedEvent,ContextStoppedEvent四个子类,Web应用相关事件RequestHandledEvent有ServletRequestHandledEvent,PortletRequestHandledEvent两个子类.
事件监听器接口:ApplicationListener<E extends ApplicationEvent>包含SmartApplicationListener子接口.
事件广播器:ApplicationEventMulticaster->AbstractApplicationEventMulticaster->SimpleApplicationEventMulticaster.
1.检查是否有名为applicationEventMulticaster的bean,如果有,就会将此bean作为事件广播器,否则将SimpleApplicationEventMulticaster实例作为事件广播器
2.找出监听器并注册到事件监听器注册表
3.调用事件广播器发布相应事件
下面是个模拟实例:
1.定义事件.
事件体系:事件,事件监听器,事件源,事件监听器注册表,事件广播器.其中,事件源是事件的产生者,事件监听器注册表就是保存事件监听器的地方,事件广播器是事件与事件监听器沟通的桥梁,负责将事件通知给事件监听器.
事件类:ApplicationEvent包含ApplicationContextEvent和RequestHandledEvent两个子类,容器事件ApplicationContextEvent有ContextClosedEvent,ContextRefreshedEvent,ContextStartedEvent,ContextStoppedEvent四个子类,Web应用相关事件RequestHandledEvent有ServletRequestHandledEvent,PortletRequestHandledEvent两个子类.
事件监听器接口:ApplicationListener<E extends ApplicationEvent>包含SmartApplicationListener子接口.
事件广播器:ApplicationEventMulticaster->AbstractApplicationEventMulticaster->SimpleApplicationEventMulticaster.
spring容器事件体系的具体实现:主要参看org.springframework.context.support.AbstractApplicationContext#refresh
...前略...
// Initialize event multicaster for this context.1.为此上下文初始化事件广播器
initApplicationEventMulticaster();
// Initialize other special beans in specific context subclasses.
onRefresh();
// Check for listener beans and register them.2:检查并注册监听器
registerListeners();
// Instantiate all remaining (non-lazy-init) singletons.
finishBeanFactoryInitialization(beanFactory);
// Last step: publish corresponding event.3:发布相应事件
finishRefresh();
...后略...
1.检查是否有名为applicationEventMulticaster的bean,如果有,就会将此bean作为事件广播器,否则将SimpleApplicationEventMulticaster实例作为事件广播器
2.找出监听器并注册到事件监听器注册表
3.调用事件广播器发布相应事件
下面是个模拟实例:
1.定义事件.
package org.exam.event;
import org.springframework.context.ApplicationContext;
import org.springframework.context.event.ApplicationContextEvent;
/**
* Created by xin on 15/1/28.
*/
public class MailSenderEvent extends ApplicationContextEvent{
private String to;
public MailSenderEvent(ApplicationContext source,String to) {
super(source);
this.to=to;
}
public String getTo() {
return to;
}
}
2.定义事件监听.
package org.exam.event;
import org.springframework.context.ApplicationListener;
public class MailSenderListener implements ApplicationListener<MailSenderEvent> {
@Override
public void onApplicationEvent(MailSenderEvent event) {
System.out.println(getClass()+":向"+event.getTo()+"发送完一封邮件!");
}
}
3.使用org.springframework.context.ApplicationContext#publishEvent来发布事件.此类必须实现ApplicationContextAware接口,以便容器启动时注入ApplicationContext实例,这样此实例才有发布事件的能力.
package org.exam.event;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ApplicationEvent;
/**
* Created by xin on 15/1/28.
*/
public class MailSender implements ApplicationContextAware {
private ApplicationContext applicationContext;
@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
this.applicationContext=applicationContext;
}
public void sendMail(String to){
System.out.println(getClass()+":模拟发送邮件:");
ApplicationEvent applicationEvent=new MailSenderEvent(applicationContext,to);
applicationContext.publishEvent(applicationEvent);
}
}
4.测试.
package org.exam.config;
import org.exam.event.MailSender;
import org.exam.event.MailSenderListener;
import org.springframework.context.ApplicationListener;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
/**
* Created by xin on 15/1/28.
*/
@Configuration
public class AppConfig {
@Bean
public ApplicationListener applicationListener(){
return new MailSenderListener();
}
@Bean
public MailSender mailSender(){
return new MailSender();
}
}
package org.exam.event;
import org.exam.config.AppConfig;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
/**
* Created by xin on 15/1/29.
*/
public class Main {
public static void main(String[] args) {
ApplicationContext context=new AnnotationConfigApplicationContext(AppConfig.class);
MailSender mailSender= (MailSender) context.getBean("mailSender");
mailSender.sendMail("xiejx618@xx.io");
}
}
更多推荐
已为社区贡献1条内容
所有评论(0)