生产者消费者问题几种实现方式

wait、notify

/**
 * 生产者消费者示例
 * 
生成N个 消费N个
 */
public class ProducerConsumerTest {

    class Producer extends Thread {
        private Queue queue;
        private int            maxSize;

        Producer(Queue queue, int maxSize) {
            this.queue = queue;
            this.maxSize = maxSize;
        }

        @Override
        public void run() {

            synchronized (queue) {
                //while 一定要放在同步代码内部
                while (true) {
                    //如果要交替打印,可将条件改为： !queue.isEmpty()
                    while (queue.size() == maxSize) {
                        try {
                            queue.wait();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                    System.out.println("生产1个");
                    queue.add(1);
                    //如果多个消费者 可改为notifyAll
                    queue.notify();
                }
            }
        }
    }

    class Consumer extends Thread {
        private Queue queue;

        Consumer(Queue queue) {
            this.queue = queue;
        }

        @Override
        public void run() {

            synchronized (queue) {
                while (true) {
                    while (queue.isEmpty()) {
                        try {
                            queue.wait();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                    System.out.println("消费1个");
                    queue.remove();
                    queue.notify();
                }
            }
        }
    }

    public static void main(String[] args) {
        Queue queue = new LinkedList<>();
        ProducerConsumerTest test = new ProducerConsumerTest();

        Producer producer = test.new Producer(queue, 10);
        Consumer consumer = test.new Consumer(queue);

        producer.start();
        consumer.start();
    }
}

lock condition

//交替打印生产和消费
public class ProducerConsumerLockTest {

    private ReentrantLock  lock      = new ReentrantLock();
    private Condition      condition = lock.newCondition();
    private int            count;


    public void set() {

        lock.lock();

        try {
            while (true) {

                while (count !=0) {
                    condition.await();
                }

                System.out.println(Thread.currentThread().getName() + "生产一个产品==");
                count++;

                condition.signal();

            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }

    }

    public void get() {

        lock.lock();
        try {
            while (true) {

                while (count ==0 ) {
                    condition.await();
                }
                System.out.println(Thread.currentThread().getName() + "消费一个产品");
                count--;

                condition.signal();

            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }
    }

    public static void main(String[] args) {

        ProducerConsumerLockTest service = new ProducerConsumerLockTest();

        Thread producerThread = new Thread("producerThread") {
            @Override
            public void run() {
                service.set();
            }
        };

        Thread consumerThread = new Thread("consumerThread") {
            @Override
            public void run() {
                service.get();
            }
        };

        producerThread.start();

        consumerThread.start();
    }
}

BlockingQueue

//一个生成 多个消费示例
public class BlockingQueueTest {

    class Producer implements Runnable {
        private BlockingQueue blockingQueue;

        Producer(BlockingQueue blockingQueue) {
            this.blockingQueue = blockingQueue;
        }

        @Override
        public void run() {
            try {
                while (true) {
                    blockingQueue.put(1);
                    System.out.println(Thread.currentThread().getName()+" put one==");

                    Thread.sleep(200);
                }
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    class Consumer implements Runnable {
        private BlockingQueue blockingQueue;

        Consumer(BlockingQueue blockingQueue) {
            this.blockingQueue = blockingQueue;
        }

        @Override
        public void run() {

            try {
                while (true) {
                    blockingQueue.take();
                    System.out.println(Thread.currentThread().getName()+" get one");

                    Thread.sleep(200);
                }
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    public static void main(String[] args) throws InterruptedException {

        BlockingQueueTest test = new BlockingQueueTest();
        BlockingQueue blockingQueue = new LinkedBlockingDeque<>(1);

        new Thread(test.new Producer(blockingQueue)).start();

        new Thread(test.new Consumer(blockingQueue)).start();
        new Thread(test.new Consumer(blockingQueue)).start();

        //exit
        Thread.sleep(10 * 1000);
        System.exit(0);
    }
}