睡眠时线程中断 [英] Thread Interrupt while sleeping

问题描述

在下面的示例中，我试图优雅地终止两个线程.消费者线程在睡眠时被中断，这应该将 isInterrupted 标志设置为 true.但是 !Thread.currentThread().isInterrupted() 对 while 循环的检查似乎仍然返回 = false，因为它不会终止使用者线程.

In the example below I am attempting to gracefully terminate both threads. The consumer thread gets interrupted while sleeping, which should set the isInterrupted flag to true. However the !Thread.currentThread().isInterrupted() check on the while loop still seems to return = false because it does not terminate the consumer thread.

将下面的代码复制粘贴到IDE中进行检查:

Copy and paste the code below into and IDE to check:

public class ThreadInterruptExample {

public static void main(String[] args) throws InterruptedException {
    LinkedBlockingQueue<String> queue = new LinkedBlockingQueue<String>(1);
    ThreadInterruptExample ie = new ThreadInterruptExample();
    Producer producer = ie.new Producer(queue);
    Consumer consumer = ie.new Consumer(queue, producer);
    producer.start();
    consumer.start();
    Thread.sleep(1000);
    producer.cancel();
    consumer.cancel();
}

class BaseQueue extends Thread {
    protected final BlockingQueue<String> queue;

    public BaseQueue(BlockingQueue<String> queue) {
        this.queue = queue;
    }

    public void cancel() {
        System.out.println(this.getName() + " - Shutting down");
        interrupt();
    }
}

class Producer extends BaseQueue {
    private final List<String> messages = Arrays.asList("a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q",
            "r", "s", "t", "u", "v", "w", "x", "y", "z");

    public Producer(BlockingQueue<String> queue) {
        super(queue);
        this.setName("Producer");
    }

    public void run() {
        try {
            for (String message : messages) {
                System.out.println(this.getName() + ": Sending " + message);
                queue.put(message);
            }
        } catch (InterruptedException e) {
            System.out.println(this.getName() + " - InterruptedException occurred");
        }
    }
}

class Consumer extends BaseQueue {
    private final BaseQueue producer;

    public Consumer(BlockingQueue<String> queue, BaseQueue producerQueue) {
        super(queue);
        this.setName("Consumer");
        producer = producerQueue;
    }

    @Override
    public void run() {
        while (!Thread.currentThread().isInterrupted()) {
            System.out.println(this.getName() +": Consumer Running");
            String message = "";
            try {
                Thread.sleep(1500);
                message = queue.take();
                System.out.println(this.getName() + ": Recevied " + message);
                if (message.equals("pill")) {
                    producer.cancel();
                    this.cancel();
                }
            } catch (InterruptedException e) {
                System.out.print(this.getName() + ": Exception occurred for: " + message);
                e.printStackTrace();
            }
        }
    }

}

}

推荐答案

您在捕获 InterruptedException 时丢弃了中断.有两种解决方案.

You are discarding the interrupt when you catch the InterruptedException. There is two solutions.

while (!Thread.currentThread().isInterrupted()) {
    try {
        Thread.sleep(1500);

    } catch (InterruptedException e) {
        Thread.currentThread.interrupt();
    }
}

或者更简单的是只在循环外捕获异常.

or much simpler is to only catch the Exception outside the loop.

try {
    while (!Thread.currentThread().isInterrupted()) {
        Thread.sleep(1500);
    }
} catch (InterruptedException e) {
    Thread.currentThread.interrupt();
}

<小时>

我认为这只是一个练习，因为使用 ExecutorService 会简单得多

---

I assume this is just an exercise as it would be far simpler to use an ExecutorService

public static void main(String[] args) throws InterruptedException {
    ExecutorService service = Executors.newSingleThreadExecutor();

    for (String message : "a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z".split(",")) {
        System.out.println(getThreadName() + ": Sending " + message);
        service.submit(() -> {
            System.out.println(getThreadName() + ": Recevied " + message);
            try {
                Thread.sleep(500);
            } catch (InterruptedException e) {
                System.out.println("--- Interrupted");
            }
        });
    }
    service.shutdown();
    service.awaitTermination(1, TimeUnit.SECONDS);
    service.shutdownNow();
}

public static String getThreadName() {
    return Thread.currentThread().getName();
}

印刷品

main: Sending a
main: Sending b
main: Sending c
main: Sending d
main: Sending e
main: Sending f
main: Sending g
main: Sending h
main: Sending i
main: Sending j
main: Sending k
main: Sending l
main: Sending m
main: Sending n
main: Sending o
main: Sending p
main: Sending q
main: Sending r
main: Sending s
main: Sending t
main: Sending u
main: Sending v
main: Sending w
main: Sending x
main: Sending y
main: Sending z
pool-1-thread-1: Recevied a
pool-1-thread-1: Recevied b
--- Interrupted

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