@EventListener 监听事件 ，在同一个虚拟机中如何保证顺序执行

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@EventListener 监听事件 ，在同一个虚拟机中如何保证顺序执行

1. 设计原理

使用有序事件监听器：@EventListener注解可以接受一个org.springframework.core.Ordered接口来指示监听器的执行顺序。通过设置相应的顺序值，来控制事件监听器的执行顺序。

2. 具体编码

2.1. 编码事件监听器

编码事件监听器:

    @Async@EventListener(classes = ThreeEvent.class)public void threeEventEventHandler(ThreeEvent event) {log.info("=====================ThreeEvent===================:name:{},order:{}",event.getName(),event.getOrder());}

编码监听事件VO并继承Ordered:

@Getter
@Setter
@ToString
public class ThreeEvent extends ApplicationEvent implements Ordered {private int order;private String  name;public ThreeEvent(int order) {super("ThreeEvent async message");this.order = order;}//======================================================public String getName() {return name;}public void setName(String name) {this.name = name;}@Overridepublic int getOrder() {return order;}
}

2.2. 制作一个生成序号方法

此方法当天调用获得的值为9999999 至 0:

public class NumUtil {public static Integer getNum(String type){StringRedisTemplate template = (StringRedisTemplate) SpringContextUtil.getApplicationContext().getBean("stringRedisStdTemplate");String today = DateUtils.format(new Date(), "yyyyMMdd");String key = StringUtils.join(type,"_", today);String numMax = "9999999";if (template.hasKey(key)) {Long decrement = template.opsForValue().decrement(key, 1L);return decrement.intValue();}template.opsForValue().set(key,numMax);template.expire(key, 24 * 60 * 60, TimeUnit.SECONDS);return Integer.valueOf(numMax);}
}

2.3. 制作测试代码

首先定义一个线程池:

@Configuration
@EnableAsync
public class ThreadPoolTaskExecutorConfig {@Bean("yzyThreadPoolExecutor")public ThreadPoolExecutor taskExecutor() {int threads = Math.min(Runtime.getRuntime().availableProcessors() * 2, 20);return new ThreadPoolExecutor(threads, threads,0L, TimeUnit.MILLISECONDS,new LinkedBlockingQueue<Runnable>(100),new NamedThreadFactory("jobThreadPoolExecutor-", false));}
}

编写要用线程池执行的方法:

    @Async("yzyThreadPoolExecutor")public void test(){ThreeEvent event1 = new ThreeEvent(NumUtil.getNum(EVENT_NUM));event1.setName("eiuyriuw");SpringContextUtil.getApplicationContext().publishEvent(event1);}

制作执行逻辑:

    @ApiOperation(value = "测试", notes = "测试")@CommonLog(methodName = "测试",className = "TestController#event1")@RequestMapping(value = "/v1/event1", method = RequestMethod.POST)public void event1(){for (int i = 0 ;i<100;i++) {test();i++;}}

2.4. 测试结果

可以看到在并发环境下，事件监听的执行顺序也可以得到保证。