在Java中实现生产者消费者(Implementing producer consumer in J

这是一门功课生产消费模式的实现。 有什么不对下面的执行。 我用Google搜索了各种实现的，但我无法理解有什么地方出了问题我的。

我有一个共享队列

我同步在同一个锁生产者和消费者

履行

共享队列：

 class SharedQueue{
    public static Queue<Integer>   queue  = new LinkedList<Integer>();
 }

生产者线程：

//The producer thread
class Producer implements Runnable{
    public void run()
    {
        synchronized (SharedQueue.queue)
        {
            if(SharedQueue.queue.size() >=5)
            {
                try {
                    SharedQueue.queue.wait();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            Random r  = new Random();

            int x = r.nextInt(10);
            System.out.println("Inside Producer" + x);

            SharedQueue.queue.offer(x);


            SharedQueue.queue.notify();

        }
    }
}

消费者线程：

class Consumer implements  Runnable{
    public void run()
    {
        synchronized (SharedQueue.queue)
        {
            if(SharedQueue.queue.size() == 0)
            {
                try {
                    SharedQueue.queue.wait();
                } catch (InterruptedException e) {
                    e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
                }
            }

            int k = SharedQueue.queue.remove();

            System.out.println("Inside consumer" + k);
        }
    }
}

主程序

public class ProducerConsumerTest {

    public static void main(String[] args)
    {

        Thread p = new Thread(new Producer());
        Thread q = new Thread(new Consumer());

        p.start();
        q.start();

    }
}

Answer 1:

尝试更换：

if(SharedQueue.queue.size() >= 5)

有：

while(SharedQueue.queue.size() >= 5)

和这个：

if(SharedQueue.queue.size() == 0)

有：

while(SharedQueue.queue.size() == 0)

打完电话后只需重新检查车况notify()

Answer 2:

我假设你想这是生产者消费者的无限循环。 对Eng.Fouad变化之上，suround都synchonized块有：

        while (true)

而在消费者中添加通知

        int k = SharedQueue.queue.remove(); 

        // make the producer active again
        SharedQueue.queue.notify();

        System.out.println("Inside consumer " + k);

Answer 3:

实现生产者消费者问题的简便方法是使用旗语。

public class Semaphore {
    int value;

    public Semaphore(int intialValue) {
        this.value = intialValue;
    }

    public synchronized void p() {
        while (value <= 0) {
            try {
                this.wait();
            } catch (InterruptedException e) {
            }
        }
        value = value - 1;
    }

    public synchronized void v() {
        value = value + 1;
        this.notify();
    }
}

public class ProducerConsumerUsingSemaphore {

    private static final int SIZE = 10;

    public static void main(String[] args) {

        Semaphore full = new Semaphore(0);
        Semaphore empty = new Semaphore(SIZE);
        Semaphore mutex = new Semaphore(1);
        Vector<Integer> sQueue = new Vector<Integer>();

        Thread producerThread = new Thread(new Runnable() {

            @Override
            public void run() {

                for (int i = 0; i < 5000; i++) {
                    empty.p();
                    mutex.p();
                    System.out.println(Thread.currentThread().getName() + " is trying to insert item " + i);
                    sQueue.add(i);
                    mutex.v();
                    full.v();
                }
            }
        });

        Thread consumerThread = new Thread(new Runnable() {

            @Override
            public void run() {
                while (true) {
                    full.p();
                    mutex.p();
                    System.out.println(Thread.currentThread().getName() + " consuming item " + sQueue.remove(0));
                    mutex.v();
                    empty.v();
                }
            }
        });

        producerThread.setName("Producer");
        consumerThread.setName("Consumer");

        consumerThread.start();
        producerThread.start();

    }
}

Answer 4:

您可以使用的ConcurrentLinkedQueue管理共享队列的生产者和消费者。 您可以使用的ConcurrentHashMap>收集的，这将有利于生产者能够同时生产和消费也可以同时使用和在另一个集合对象的生产者，消费者哪里能找到它的关键，并从ConcurrentHashMap的消耗它>保持生成的密钥。

Answer 5:

public class ProducerAndConsumer {
    public static void main(String a[]) {
        Resource resource = new Resource();
        Producer producer = new Producer(resource);
        Consumer consumer = new Consumer(resource);
        producer.start();
        consumer.start();

    }
}

class Resource {
    private int item = 0;
    boolean flag = true;

    public void getItem() {
        while (true) {
            synchronized (this) {
                if (!flag) {
                    try {
                        System.out.println("Consumer consume item :" + item);
                        flag = true;
                        Thread.sleep(10);
                        notify();
                        wait();
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
            }
        }

    }

    public void setItem() {
        while (true) {
            synchronized (this) {

                if (flag) {
                    try {
                        item++;
                        System.out.println("Producer creating item :" + item);
                        flag = false;
                        Thread.sleep(10);
                        notify();
                        wait();
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }

            }
        }
    }

}

class Producer extends Thread {
    Resource resource = null;

    Producer(Resource resource) {
        this.resource = resource;
    }

    @Override
    public void run() {
        resource.setItem();
    }
}

class Consumer extends Thread {
    Resource resource = null;

    Consumer(Resource resource) {
        this.resource = resource;
    }

    @Override
    public void run() {
        resource.getItem();
    }
}

文章来源: Implementing producer consumer in Java