事件源：ApplicationContext。publishEvent()方法：用于主动触发容器事件。事件：ApplicationEvent类,容器事件，必须由ApplicationContext发布。事件监听器：ApplicationListener接口，可由容器中任何监听器Bean担任。onApplicationEvent(ApplicationEvent event)：每当容器内发生任何事件时，此方法都被触发

容器事件类需继承ApplicationEvent类，容器事件的监听器类需实现ApplicationListener接口。

下面给出一个例子

1.首先定义一个EmailEvent类，继承ApplicationEvent类

public class EmailEvent extends ApplicationEvent {    private String address;    private String text;    public EmailEvent(Object source) {        super(source);    }    public EmailEvent(Object source, String address, String text) {        super(source);        this.address = address;        this.text = text;    }    public String getAddress() {        return address;    }    public void setAddress(String address) {        this.address = address;    }    public String getText() {        return text;    }    public void setText(String text) {        this.text = text;    }}

2，定义一个EmailNotifier类，实现ApplicationListener接口，并复写onApplicationEvent()方法

public class EmailNotifier implements ApplicationListener {    @Override    public void onApplicationEvent(ApplicationEvent applicationEvent) {        if (applicationEvent instanceof EmailEvent){            EmailEvent emailEvent = (EmailEvent) applicationEvent;            System.out.println("需要发送邮件的接收地址： " + emailEvent.getAddress());            System.out.println("需要发送邮件的邮件正文： " + emailEvent.getText());        }else {            System.out.println("容器本身的事件： " + applicationEvent);        }    }}

3.将监听器配置在容器中

<bean class="org.spring.listener.EmailNotifier"/>

4.编写主程序main

public class SpringTest {    public static void main(String[] args){        ApplicationContext ctx = new ClassPathXmlApplicationContext("spring-config.xml");//        EmailEvent ele = new EmailEvent("hello","spring_test@163.com","this is a test");//        ctx.publishEvent(ele);    }}

程序到此结束，运行结果如下：

容器本身的事件： org.springframework.context.event.ContextRefreshedEvent[source=org.springframework.context.support.ClassPathXmlApplicationContext@b81eda8: startup date [Thu Dec 04 20:20:52 CST 2014]; root of context hierarchy]

若取消main中的注释，即，使用publishEvent()来触发事件，运行结果如下：

容器本身的事件： org.springframework.context.event.ContextRefreshedEvent[source=org.springframework.context.support.ClassPathXmlApplicationContext@b81eda8: startup date [Thu Dec 04 20:24:03 CST 2014]; root of context hierarchy]需要发送邮件的接收地址： spring_test@163.com需要发送邮件的邮件正文： this is a test

Spring---ApplicationContext的事件机制