生产者消费者问题--BlockingQueue

# 代码：

public class App {

    public static void main(String[] args) {

        BlockingQueue<Integer> queue = new ArrayBlockingQueue<>(6);
        Producer producer = new Producer(queue);
        Consumer consumer = new Consumer(queue);

        producer.produce(5);
        consumer.consume(4);
        producer.produce(3);
        consumer.consume(2);
    }
}

class Producer {
    private BlockingQueue<Integer> queue;

    public Producer(BlockingQueue<Integer> queue) {
        this.queue = queue;
    }

    public void produce(final int val) {
        new Thread() {
            public void run() {
                try {
                    int surplus = val;
                    while (surplus > 0) {
                        queue.put(1024);
                        surplus--;
                        System.out.printf("%s plan to produce (%d), actually produce (%d), queue size (%d) 
",
                                Thread.currentThread().getName(), val, 1, queue.size());
                    }
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }.start();
    }
}

class Consumer {
    private BlockingQueue<Integer> queue;

    public Consumer(BlockingQueue<Integer> queue) {
        this.queue = queue;
    }

    public void consume(final int val) {
        new Thread() {
            public void run() {
                int surplus = val;
                try {
                    while (surplus > 0) {
                        queue.take();
                        surplus--;
                        System.out.printf("%s plan to consume (%d), actually consume (%d), queue size (%d) 
",
                                Thread.currentThread().getName(), val, 1, queue.size());
                    }
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

            }
        }.start();
    }
}

# 输出：

Thread-0 plan to produce (5), actually produce (1), queue size (1)
Thread-3 plan to consume (2), actually consume (1), queue size (0)
Thread-2 plan to produce (3), actually produce (1), queue size (1)
Thread-1 plan to consume (4), actually consume (1), queue size (0)
Thread-2 plan to produce (3), actually produce (1), queue size (1)
Thread-3 plan to consume (2), actually consume (1), queue size (0)
Thread-0 plan to produce (5), actually produce (1), queue size (1)
Thread-2 plan to produce (3), actually produce (1), queue size (1)
Thread-1 plan to consume (4), actually consume (1), queue size (0)
Thread-0 plan to produce (5), actually produce (1), queue size (2)
Thread-1 plan to consume (4), actually consume (1), queue size (1)
Thread-1 plan to consume (4), actually consume (1), queue size (1)
Thread-0 plan to produce (5), actually produce (1), queue size (2)
Thread-0 plan to produce (5), actually produce (1), queue size (2)

# 有四个线程参与了这个过程，两个生产者，两个消费者