Java 并发实践 “Listing 7.9. Interrupting a task in a dedicated thread.” 。预定 taskThread.interrupt() 的目的是什么？

Question

我正在阅读 Java Concurrency in Practice 并遇到以下代码片段。

public static void timedRun(final Runnable r,
                            long timeout, TimeUnit unit)
        throws InterruptedException {
    class RethrowableTask implements Runnable {
        private volatile Throwable t;
        public void run() {
            try { r.run(); }
            catch (Throwable t) { this.t = t; }
        }
        void rethrow() {
            if (t != null)
                throw launderThrowable(t);
        }
    }
    RethrowableTask task = new RethrowableTask();
    final Thread taskThread = new Thread(task);
    taskThread.start();
    cancelExec.schedule(new Runnable() {
        public void run() { taskThread.interrupt(); }
    }, timeout, unit);
    taskThread.join(unit.toMillis(timeout));
    task.rethrow();
}

timedRun方法用于运行任务 r一个时间范围内。此功能可以通过 taskThread.join(unit.toMillis(timeout)); 实现.所以， 为什么我们需要预定 taskThread.interrupt(); ?

Answer 1

This feature can be implemented by taskThread.join(unit.toMillis(timeout));

这不是真的。加入时限刚刚 determines when the joining thread will give up waiting .它不会影响被超时限制的线程。预定 interrupt告诉正在运行的线程在超时到期后自行关闭。如果它不存在，该线程将继续消耗资源。据推测，该方法的重点是防止这种情况发生。