一. 点睛
Spring
的事件(Application
Event
)为Bean
与Bean
之间的消息通信提供了支持。当一个Bean
处理完一个任务之后,希望另外一个Bean
知道并能做相应的处理,这时我们就需要让另外一个Bean
监听当前Bean
所发送的事件。
Spring的事件需要遵循如下流程:
1. 自定义事件,继承
ApplicationEvent
2. 定义事件监听器,实现ApplicationListener
二. 示例
1.自定义事件
package org.light4j.sping4.usually.event;
import org.springframework.context.ApplicationEvent;
public class DemoEvent extends ApplicationEvent{
private static final long serialVersionUID = 1L;
private String msg;
public DemoEvent(Object source,String msg) {
super(source);
this.msg = msg;
}
public String getMsg() {
return msg;
}
public void setMsg(String msg) {
this.msg = msg;
}
}
2. 事件监听器
package org.light4j.sping4.usually.event;
import org.springframework.context.ApplicationListener;
import org.springframework.stereotype.Component;
@Component
public class DemoListener implements ApplicationListener<DemoEvent> {//①
public void onApplicationEvent(DemoEvent event) {//②
String msg = event.getMsg();
System.out.println("我(bean-demoListener)接受到了bean-demoPublisher发布的消息:"+ msg);
}
}
代码解释:
① 实现
ApplicationListener
接口,并指定监听的事件类型。
② 使用onApplicationEvent
方法对消息进行接受处理。
3. 事件发布类
package org.light4j.sping4.usually.event;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.stereotype.Component;
@Component
public class DemoPublisher {
@Autowired
ApplicationContext applicationContext;//①
public void publish(String msg){
applicationContext.publishEvent(new DemoEvent(this, msg));//②
}
}
代码解释:
① 注入
ApplicationContext
用来发布事件。
② 使用ApplicationContext
的publishEvent
方法来进行发布。
4. 配置类
package org.light4j.sping4.usually.event;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
@Configuration
@ComponentScan("org.light4j.sping4.usually.event")
public class EventConfig {
}
5. 运行
package org.light4j.sping4.usually.event;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
public class Main {
public static void main(String[] args) {
AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(EventConfig.class);
DemoPublisher demoPublisher = context.getBean(DemoPublisher.class);
demoPublisher.publish("hello application event");
context.close();
}
}
运行结果如下图所示:
6. 源代码示例:
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未经允许不得转载:人生设计师 » Spring4.x常用配置(五):Spring事件