springboot进行事件监听有四种方式:
1.手工向ApplicationContext中添加监听器
2.将监听器装载入spring容器
3.在application.properties中配置监听器
4.通过@EventListener注解实现事件监听
讲到事件监听,这里我们说下自定义事件和自定义监听器类的实现方式:
自定义事件:继承自ApplicationEvent抽象类,然后定义自己的构造器
自定义监听:实现ApplicationListener接口,然后实现onApplicationEvent方法
下面讲下4种事件监听的具体实现
方式1.
首先创建MyListener1类
public class MyListener1 implements ApplicationListener<MyEvent>
{
Logger logger = Logger.getLogger(MyListener1.class);
public void onApplicationEvent(MyEvent event)
{
logger.info(String.format("%s监听到事件源:%s.", MyListener1.class.getName(), event.getSource()));
}
}
然后在springboot应用启动类中获取ConfigurableApplicationContext上下文,装载监听
@SpringBootApplication
public class LisenterApplication
{
public static void main(String[] args)
{
ConfigurableApplicationContext context = SpringApplication.run(LisenterApplication.class, args);
//装载监听
context.addApplicationListener(new MyListener1());
}
}
方式2.
创建MyListener2类,并使用@Component注解将该类装载入spring容器中
@Component
public class MyListener2 implements ApplicationListener<MyEvent>
{
Logger logger = Logger.getLogger(MyListener2.class);
public void onApplicationEvent(MyEvent event)
{
logger.info(String.format("%s监听到事件源:%s.", MyListener2.class.getName(), event.getSource()));
}
}
方式3.
首先创建MyListener3类
public class MyListener3 implements ApplicationListener<MyEvent>
{
Logger logger = Logger.getLogger(MyListener3.class);
public void onApplicationEvent(MyEvent event)
{
logger.info(String.format("%s监听到事件源:%s.", MyListener3.class.getName(), event.getSource()));
}
}
然后在application.properties中配置监听
context.listener.classes=com.listener.MyListener3
方式4.
创建MyListener4类,该类无需实现ApplicationListener接口,使用@EventListener装饰具体方法
@Component
public class MyListener4
{
Logger logger = Logger.getLogger(MyListener4.class);
@EventListener
public void listener(MyEvent event)
{
logger.info(String.format("%s监听到事件源:%s.", MyListener4.class.getName(), event.getSource()));
}
}
自定义事件代码如下:
@SuppressWarnings("serial")
public class MyEvent extends ApplicationEvent
{
public MyEvent(Object source)
{
super(source);
}
}
进行测试(在启动类中加入发布事件的逻辑):
@SpringBootApplication
public class LisenterApplication
{
public static void main(String[] args)
{
ConfigurableApplicationContext context = SpringApplication.run(LisenterApplication.class, args);
//装载事件
context.addApplicationListener(new MyListener1());
//发布事件
context.publishEvent(new MyEvent("测试事件."));
}
}
启动后,日志打印如下:
2018-06-15 10:51:20.198 INFO 4628 --- [ main] com.listener.MyListener3 : com.listener.MyListener3监听到事件源:测试事件..
2018-06-15 10:51:20.198 INFO 4628 --- [ main] com.listener.MyListener4 : com.listener.MyListener4监听到事件源:测试事件..
2018-06-15 10:51:20.199 INFO 4628 --- [ main] com.listener.MyListener2 : com.listener.MyListener2监听到事件源:测试事件..
2018-06-15 10:51:20.199 INFO 4628 --- [ main] com.listener.MyListener1 : com.listener.MyListener1监听到事件源:测试事件..
由日志打印可以看出,SpringBoot四种事件的实现方式监听是有序的