生产者-使用者例子
好久不写东西了，写点小东西吧，呵呵
这是一个简单的生产者－消费者例子（取自java 6.0 api介绍java.util.concurrent 接口 BlockingQueue时举的例子）
class Producer implements Runnable { private final BlockingQueue queue; Producer(BlockingQueue q) { queue = q; } public void run() { try { while(true) { queue.put(produce()); } } catch (InterruptedException ex) { ... handle ...} } Object produce() { ... } } class Consumer implements Runnable { private final BlockingQueue queue; Consumer(BlockingQueue q) { queue = q; } public void run() { try { while(true) { consume(queue.take()); } } catch (InterruptedException ex) { ... handle ...} } void consume(Object x) { ... } } class Setup { void main() { BlockingQueue q = new SomeQueueImplementation(); Producer p = new Producer(q); Consumer c1 = new Consumer(q); Consumer c2 = new Consumer(q); new Thread(p).start(); new Thread(c1).start(); new Thread(c2).start(); } } ?
这个例子非常易于理解，特征明显，属于典型案例，但我们平时的应用一般不会无限循环下去，我们需要消费者在生产者结束后把queue中的数据获取出来、做完相应的操作以后结束生产消费过程。 针对该需求可以修改一下程序，做一个单生产者的例子，如下：
class Producer implements Runnable { private final BlockingQueue queue; Producer(BlockingQueue q) { queue = q; } public void run() { try { while(生产条件) { queue.put(produce()); } } catch (InterruptedException ex) { ... handle ...} } Object produce() { ... } } class Consumer implements Runnable { private final BlockingQueue queue; private Thread p; Consumer(BlockingQueue q,Thread producer) { queue = q; p = producer;} public void run() { try { while(!p.isAlive()||!queue.isEmpty()) {//循环直到生产者线程结束并且把queue中的数据全部获取完 consume(queue.take()); } } catch (InterruptedException ex) { ... handle ...} } void consume(Object x) { ... } } class Setup { void main() { BlockingQueue q = new SomeQueueImplementation(); Producer p = new Producer(q); Consumer c1 = new Consumer(q); Consumer c2 = new Consumer(q); new Thread(p).start(); new Thread(c1).start(); new Thread(c2).start(); } } ?
有时候会有多生产者，再写一个多生产者的例子，如下：
public class Test { private ExecutorService producerPool = Executors.newFixedThreadPool(5); private ExecutorService consumerPool = Executors.newFixedThreadPool(5); private BlockingQueue queue = new ArrayBlockingQueue(100); public void t() { for (int i = 0; i 0) { String s = null; try { s = queue.take(); System.out.println("get a product:"+s); } catch (InterruptedException e) { e.printStackTrace(); } } System.out.println("consumer-" + Thread.currentThread().getName() + " is done!"); } }; consumerPool.submit(consumer); } consumerPool.shutdown(); } public static void main(String[] args){ new Test().t(); } } ?