讨论一个多线程问题

CanadianTire 2009-12-09 01:38:14

很简单的生产消费者例子，我想问一下，在类FactoryStock中
方法getProduct()里的notifyAll()我注释上和取消注释效果一样，至少我运行很久没有发现死锁，这行代码到底是否需要加在这里呢？请指教。
见代码：
1。



public class FactoryStock

{

    public String message="";

    public boolean hasStock = false;

    

    public synchronized String getProduct()

    {

        while(!hasStock)

        {

            try

            {

                System.out.println("Waiting in consumer");

                wait();

                Thread.sleep(2000);

            }

            catch(InterruptedException e)

            {

                

            }

        }

        hasStock = false;

        //notifyAll();

        return this.message;

    }

    

    public synchronized void putProduct(String productName)

    {

        while(hasStock)

        {

            try

            {

                System.out.println("Waiting in producer "+productName);

                wait();

                Thread.sleep(2000);

           }

            catch(InterruptedException e)

            {

                

            }

        }

        hasStock = true;

        this.message = "This is product:"+productName;

        notifyAll();

    }

}

2。



public class ProducerThread implements Runnable

{

    private FactoryStock stock;

    private String producerName;

    

    public ProducerThread(String producerName,FactoryStock stock)

    {

        this.stock = stock;

        this.producerName = producerName;

    }



    public void run()

    {

        // TODO Auto-generated method stub

        int i=1;

        while(true)

        {

            stock.putProduct("Product name:"+producerName+"["+i+++"]");

            System.out.println("Producer "+producerName+" put product:"+i);

        }

    }



}

3。



class consumerThread implements Runnable

{

	private FactoryStock stock;

	private String consumerName;

	

	public consumerThread(String consumerName,FactoryStock stock)

	{

		this.stock = stock;

		this.consumerName=consumerName;

	}

	

	public void run()

	{

		while(true)

		{

			System.out.println("Consumer "+consumerName+" get product:"+stock.getProduct());

		}

	}

}

4。



public class TestFactory

{



    /**

     * @param args

     */

    public static void main(String[] args)

    {

        // TODO Auto-generated method stub

        FactoryStock stock = new FactoryStock();

        Thread consumer1 = new Thread(new consumerThread("Consumer 1",stock));

        Thread consumer2 = new Thread(new consumerThread("Consumer 2",stock));

        Thread consumer3 = new Thread(new consumerThread("Consumer 3",stock));

        Thread consumer4 = new Thread(new consumerThread("Consumer 4",stock));

        Thread consumer5 = new Thread(new consumerThread("Consumer 5",stock));

        Thread consumer6 = new Thread(new consumerThread("Consumer 6",stock));

        Thread consumer7 = new Thread(new consumerThread("Consumer 7",stock));

        Thread consumer8 = new Thread(new consumerThread("Consumer 8",stock));

        Thread consumer9 = new Thread(new consumerThread("Consumer 9",stock));

        Thread consumer10 = new Thread(new consumerThread("Consumer 10",stock));

        Thread producer1 = new Thread(new ProducerThread("Producer 1",stock));

        Thread producer2 = new Thread(new ProducerThread("Producer 2",stock));

        Thread producer3 = new Thread(new ProducerThread("Producer 3",stock));

        Thread producer4 = new Thread(new ProducerThread("Producer 4",stock));

        Thread producer5 = new Thread(new ProducerThread("Producer 5",stock));

        Thread producer6 = new Thread(new ProducerThread("Producer 6",stock));

        Thread producer7 = new Thread(new ProducerThread("Producer 7",stock));

        Thread producer8 = new Thread(new ProducerThread("Producer 8",stock));

        Thread producer9 = new Thread(new ProducerThread("Producer 9",stock));

        Thread producer10 = new Thread(new ProducerThread("Producer 10",stock));

        Thread producer11 = new Thread(new ProducerThread("Producer 11",stock));

        Thread producer12 = new Thread(new ProducerThread("Producer 12",stock));

        Thread producer13 = new Thread(new ProducerThread("Producer 13",stock));

        Thread producer14 = new Thread(new ProducerThread("Producer 14",stock));

        Thread producer15 = new Thread(new ProducerThread("Producer 15",stock));

        Thread producer16 = new Thread(new ProducerThread("Producer 16",stock));

        consumer1.start();

        consumer2.start();

        consumer3.start();

        consumer4.start();

        consumer5.start();

        consumer6.start();

        consumer7.start();

        consumer8.start();

        consumer9.start();

        consumer10.start();

        producer1.start();

        producer2.start();

        producer3.start();

        producer4.start();

        producer5.start();

        producer6.start();

        producer7.start();

        producer8.start();

        producer9.start();

        producer10.start();

        producer11.start();

        producer12.start();

        producer13.start();

        producer14.start();

        producer15.start();

        producer16.start();

    }



}