java - 延迟启动的单线程

Question

我想做的是：按一个按钮更改简单的值。如果值保持 3 秒不变，我想执行我的方法。所以我需要一个线程，它会在每次按钮单击时启动（并杀死所有其他线程）。我知道

Executor executor = Executors.newSingleThreadScheduledExecutor();

但不能有延迟。这样做的最佳做法是什么？

Answer 1

您可以简单地使用旧Thread类或Runnable接口：单击按钮后立即启动线程，Thread.sleep(3000)作为第一条指令执行，然后检查值是否不变。在启动线程之前检查另一个线程是否已经存在，如果有的话，调用interrupt()它并处理它InterruptedException以优雅地终止它。

如果您想使用较新的并发 API，请注意Executors.newSingleThreadScheduledExecutor()返回 a ScheduledExecutorService（不是简单的Executor），并且顾名思义，它允许延迟启动线程。检查Javadoc。

Answer 2

您可以使用简单Thread的启动-停止/中断，也可以使用 API 之类的ScheduledExecutorService. 下面
是如何处理的示例ScheduledExecutorService

//Start as many threads as you want upon button click... (since you said i want to kill all other threads, so i assume you want to start some threads soon upon button click)
            ScheduledExecutorService service = Executors.newScheduledThreadPool(3);
            service.schedule(new Thread(), 0, TimeUnit.SECONDS);
            service.schedule(new Thread(), 0, TimeUnit.SECONDS);
            service.schedule(new Thread(), 0, TimeUnit.SECONDS);

            //Start single thread after 3 seconds.
            ScheduledExecutorService serviceCheck = Executors.newScheduledThreadPool(3);
            serviceCheck.schedule(new Thread(), 3, TimeUnit.SECONDS);
            //In this thread created using "serviceCheck", check with value has not changed then use `service.shutdownNow();` to shutdown all previously started threads and then do whatever you want.