如何在使用者线程面临异常时停止生产者线程

Question

我在使用ArrayBlockingQueue时遇到了生产者和消费者的情况。如果使用者线程面临异常，如何停止生产者线程。我需要生产者停止等待队列是空的。我已经诱导了一个强制运行时异常。但是程序不会退出。生产者一直在等待，因为队列是空的。有人能帮忙吗

public class ServiceClass implements Runnable{

    private final static BlockingQueue<Integer> processQueue = new ArrayBlockingQueue<>(10);
    private static final int CONSUMER_COUNT = 1;
    private boolean isConsumerInterrupted = false;

    private boolean isConsumer = false;
    private static boolean producerIsDone = false;

    public ServiceClass(boolean consumer,boolean isConsumerInterrupted) {
        this.isConsumer = consumer;
        this.isConsumerInterrupted = isConsumerInterrupted;
    }

    public static void main(String[] args) {

        long startTime = System.nanoTime();

        ExecutorService producerPool = Executors.newFixedThreadPool(1);
        producerPool.submit(new ServiceClass(false,false)); // run method is
                                                         // called   
        // create a pool of consumer threads to parse the lines read
        ExecutorService consumerPool = Executors.newFixedThreadPool(CONSUMER_COUNT);
        for (int i = 0; i < CONSUMER_COUNT; i++) {
            consumerPool.submit(new ServiceClass(true,false)); // run method is
                                                            // called
        }
        producerPool.shutdown();
        consumerPool.shutdown();

        while (!producerPool.isTerminated() && !consumerPool.isTerminated()) {
        }

        long endTime = System.nanoTime();
        long elapsedTimeInMillis = TimeUnit.MILLISECONDS.convert((endTime - startTime), TimeUnit.NANOSECONDS);
        System.out.println("Total elapsed time: " + elapsedTimeInMillis + " ms");

    }



    @Override
    public void run() {
        if (isConsumer) {
            consume();
        } else {
            readFile(); //produce data by reading a file
        }
    }

    private void readFile() {
        //Path file = Paths.get("c:/temp/my-large-file.csv");
        try
        {

            for(int i =0;i<10000;i++) {
                if(isConsumerInterrupted) {
                    break;
                }
                processQueue.put(i);
                System.out.println("produced:" + i+"------"+processQueue.size());

            }
            //Java 8: Stream class


        } catch (Exception e){
            e.printStackTrace();
        }

        producerIsDone = true; // signal consumer
        System.out.println(Thread.currentThread().getName() + " producer is done");
    }

    private void consume() {
        try {
            while (!producerIsDone || (producerIsDone && !processQueue.isEmpty())) {

                System.out.println("consumed:" + processQueue.take()+"------"+processQueue.size());
                throw new RuntimeException();

                //System.out.println(Thread.currentThread().getName() + ":: consumer count:" + linesReadQueue.size());                
            }
            System.out.println(Thread.currentThread().getName() + " consumer is done");
        } catch (Exception e) {
            isConsumerInterrupted=true;
        }


    }




}

Answer 1

您正在使用标志isconsumerinterrupted来终止生成器线程。这是不对的。消费者不使用队列中的元素，生产者一直生产，直到队列满了，然后开始阻塞，直到队列非满。然后，当使用者抛出RuntimeException时，它会设置标志，而生产者线程没有机会检查标志，因为没有一个使用者使用队列中的元素，这样生产者就可以从等待状态中出现。一种选择是使用将来，并在使用者抛出与设置标志相反的异常时取消它。由于processqueue.put响应中断，因此它将成功终止生成器线程。如果在等待期间中断，则抛出interruptedexception。看起来是这样的。

private static Future<?> producerFuture = null;
public static void main(String[] args) {

    // Remainder omitted.
    producerFuture = producerPool.submit(new ServiceClass(false, false)); 
    // ...
}

private void consume() {
    try {
        // ...
    } catch (Exception e) {
        producerFuture.cancel(true);
    }
}