这篇文章给大家分享的是有关如何实现Spring事件发布监听、顺序监听和异步监听的内容。小编觉得挺实用的，因此分享给大家做个参考，一起跟随小编过来看看吧。
1. Spring的事件通知
Spring的事件通知本质上就是发布-订阅，即生产者-消费者；体现了观察者设计模式或者回调通知，那么Spring的事件是如何使用的？
有3要素：发布者-->事件-->监听者
2. Spring事件通知使用
Spring的事件必须依赖Spring容器，所以我在写demo的时候，需要Spring-boot-starter。
<dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter</artifactId> <version>2.1.1.RELEASE</version> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <version>1.18.4</version> </dependency> </dependencies>
2.1 Spring的事件
Spring的事件定义在ApplicationEvent类中，我们可以根据自己的需要自定义事件实体javabean。
@Data
public class TestSpringEvent extends ApplicationEvent {
/**
* Create a new ApplicationEvent.
*
* @param source the object on which the event initially occurred (never {@code null})
*/
public TestSpringEvent(Object source) {
super(source);
}
private Integer code;
private String message;
}跟踪源码：
public abstract class ApplicationEvent extends EventObject {
/** use serialVersionUID from Spring 1.2 for interoperability. */
private static final long serialVersionUID = 7099057708183571937L;
/** System time when the event happened. */
private final long timestamp;
/**
* Create a new ApplicationEvent.
* @param source the object on which the event initially occurred (never {@code null})
*/
public ApplicationEvent(Object source) {
super(source);
this.timestamp = System.currentTimeMillis();
}
/**
* Return the system time in milliseconds when the event happened.
*/
public final long getTimestamp() {
return this.timestamp;
}
}可以看出ApplicationEvent有属性时间戳，即事件的产生的时间，并有Object source属性，这个source是有特定意义的，官方的doc是The object>public class EventObject implements java.io.Serializable {
private static final long serialVersionUID = 5516075349620653480L;
/**
* The object on which the Event initially occurred.
*/
protected transient Object source;
/**
* Constructs a prototypical Event.
*
* @param source The object on which the Event initially occurred.
* @exception IllegalArgumentException if source is null.
*/
public EventObject(Object source) {
if (source == null)
throw new IllegalArgumentException("null source");
this.source = source;
}
/**
* The object on which the Event initially occurred.
*
* @return The object on which the Event initially occurred.
*/
public Object getSource() {
return source;
}
/**
* Returns a String representation of this EventObject.
*
* @return A a String representation of this EventObject.
*/
public String toString() {
return getClass().getName() + "[source=" + source + "]";
}
}如何实现Spring事件发布监听、顺序监听和异步监听
