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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;
    }

    @Override
    public 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。