我正在玩 java.util.concurrent
包并使用它的接口(interface)/类来了解它们是如何工作的。我创建了一个 BlockingQueue
实例(ArrayBlockingQueue
imlpementation)。并创建了 50 个 Rannable
类型的消费者和 50 个生产者。然后使用 Executors.newFixedThreadPool(4)
创建一个大小为 4 的线程池,并将我所有的消费者/生产者提交给 threadPool
(ExecutorService)。但最终打印过程我认为它是死锁
-ing。谁能解释为什么线程安全队列会死锁!?下面是我的代码:
消费者:
public class ArrayBlockingQueueConsumer implements Runnable{
BlockingQueue<Integer> blockingQueue;
int consumerNumber = 0;
public ArrayBlockingQueueConsumer(BlockingQueue<Integer> blockingQueue, int consumerNumber) {
this.blockingQueue = blockingQueue;
this.consumerNumber = consumerNumber;
}
public void run() {
int i = 0;
while(i<60) {
System.out.printf("Consumer %d going take %d from blocking queue\n", consumerNumber, i);
try {
int x = blockingQueue.take();
System.out.println("The number " + x + "is taken from the queue.");
} catch (InterruptedException e) {
System.out.printf("Consumer %d interrupted while adding %d to blocking queue\n", consumerNumber, i);
e.printStackTrace();
}
i++;
}
}
}
制作人:
public class ArrayBlockingQueueProducer implements Runnable{
BlockingQueue<Integer> blockingQueue;
int producerNumber = 0;
public ArrayBlockingQueueProducer(BlockingQueue<Integer> blockingQueue, int producerNumber) {
this.blockingQueue = blockingQueue;
this.producerNumber = producerNumber;
}
public void run() {
int i = 0;
while(i<60) {
System.out.printf("Consumer %d going to add %d to blocking queue\n", producerNumber, i);
blockingQueue.add(i);
System.out.printf("Consumer %d added %d to blocking queue\n", producerNumber, i);
i++;
}
}
}
执行器类(main()方法类):
public class BlockingQueueExecutor {
public static void main(String[] args) {
BlockingQueue<Integer> blockingQueue = new ArrayBlockingQueue<Integer>(50);
ArrayBlockingQueueConsumer[] consumers = new ArrayBlockingQueueConsumer[200];
ArrayBlockingQueueProducer[] producers = new ArrayBlockingQueueProducer[200];
System.out.println("Hello hello :D");
for (int i = 0; i < 200; i++) {
consumers[i] = new ArrayBlockingQueueConsumer(blockingQueue, i+1);
producers[i] = new ArrayBlockingQueueProducer(blockingQueue, i+1);
}
ExecutorService threadPool = Executors.newFixedThreadPool(4);
for (int i = 0; i < 200; i++) {
threadPool.execute(consumers[i]);
threadPool.execute(producers[i]);
}
threadPool.shutdown();
}
}
我在消费者/生产者中运行了从 0 到 60 的循环,这样他们就可以在找不到任何元素或发现队列已满时抛出异常,具有讽刺意味的是,没有一个生产者/消费者抛出任何异常。
最佳答案
I ran the loops in consumers/producers from 0 to 60 so that they can throw exception when they don't find any element or find queue full respectively, ironically none of the producers/consumers threw any exception.
take()
在队列为空时不会抛出异常。它一直等到元素可用。
E java.util.concurrent.BlockingQueue.take() throws InterruptedException
Retrieves and removes the head of this queue, waiting if necessary until an element becomes available.
关于java - 将 add() 和 take() 元素添加到 BlockingQueue 时死锁,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/46871168/