Java 线程与并发研究系列五(生产者与消费者)

来源：互联网发布：手机打字软件编辑：程序博客网时间：2024/06/10 05:28

生产者与消费者问题是了解多线程的基本实例，就像hello world之于语言学习，下面我们就编写一个生产者-消费者的示例

public class Test {public static void main(String[] args) {Storage storage = new Storage(20);ExecutorService exes = Executors.newCachedThreadPool();for (int i = 0; i < 10; i++) {exes.submit(new Producer(storage));exes.submit(new Consumer(storage));}try {TimeUnit.SECONDS.sleep(5);} catch (InterruptedException e) {e.printStackTrace();}exes.shutdownNow();}}class Producer implements Runnable{Storage storage;public Producer(Storage storage){this.storage = storage;}@Overridepublic void run() {try {storage.produce();} catch (InterruptedException e) {e.printStackTrace();}}}class Consumer implements Runnable{Storage storage;public Consumer(Storage storage){this.storage = storage;}@Overridepublic void run() {try {storage.consume();} catch (InterruptedException e) {e.printStackTrace();}}}class Storage{private static final int max = 30;private int num;public Storage(int num){this.num = num;}public synchronized void produce()throws InterruptedException{while(num>=max){wait();}num+=5;System.out.println("生产产品数:"+5+" 仓库还剩产品数："+num);notifyAll();}public synchronized void consume()throws InterruptedException{while(num<7){wait();}num-=7;System.out.println("消费产品数："+7+" 仓库还剩产品数："+num);notifyAll();}}

以上是通过wait()和notifyAll synchronized关键字进行线程之间的同步，现在我们尝试另外一种方法，通过使用同步队列来解决任务的协作

问题，如果消费者试图从队列中获取对象，而此时队列为空，阻塞队列就会挂起消费者线程，同理如果参考已经满了，生产者试图向队列

中添加对象，此时队列将挂起生产者线程。

public class MyData{public static void main(String[] args) {Storage storage = new Storage();ExecutorService exes = Executors.newCachedThreadPool();for (int i = 0; i < 10; i++) {exes.submit(new Producer(storage));exes.submit(new Consumer(storage));}try {TimeUnit.SECONDS.sleep(5);} catch (InterruptedException e) {e.printStackTrace();}exes.shutdownNow();System.out.println("仓库最后剩余数："+storage.queue.size());}}class Producer implements Runnable{Storage storage;public Producer(Storage storage){this.storage = storage;}@Overridepublic void run() {try {storage.produce();} catch (InterruptedException e) {e.printStackTrace();}}}class Consumer implements Runnable{Storage storage;public Consumer(Storage storage){this.storage = storage;}@Overridepublic void run() {try {storage.consume();} catch (InterruptedException e) {e.printStackTrace();}}}class Storage{private static final int max = 30;public BlockingQueue<Product> queue;public Storage(){this.queue = new LinkedBlockingQueue<Product>();}public void produce()throws InterruptedException{if(queue.size()<max){queue.put(new Product());System.out.println("生产一个产品，仓库产品个数:"+queue.size());}}public void consume()throws InterruptedException{if(queue.size()>0){queue.take();System.out.println("消费一个产品，仓库产品个数:"+queue.size());}}}class Product{public Product(){}}

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