Java線程生產者消費者問題
如何使用線程解決生產者消費者問題?
解決方法
下麵的示例演示如何使用線程來解決生產者消費者問題。
public class ProducerConsumerTest { public static void main(String[] args) { CubbyHole c = new CubbyHole(); Producer p1 = new Producer(c, 1); Consumer c1 = new Consumer(c, 1); p1.start(); c1.start(); } } class CubbyHole { private int contents; private boolean available = false; public synchronized int get() { while (available == false) { try { wait(); } catch (InterruptedException e) { } } available = false; notifyAll(); return contents; } public synchronized void put(int value) { while (available == true) { try { wait(); } catch (InterruptedException e) { } } contents = value; available = true; notifyAll(); } } class Consumer extends Thread { private CubbyHole cubbyhole; private int number; public Consumer(CubbyHole c, int number) { cubbyhole = c; this.number = number; } public void run() { int value = 0; for (int i = 0; i < 10; i++) { value = cubbyhole.get(); System.out.println("Consumer #" + this.number + " got: " + value); } } } class Producer extends Thread { private CubbyHole cubbyhole; private int number; public Producer(CubbyHole c, int number) { cubbyhole = c; this.number = number; } public void run() { for (int i = 0; i < 10; i++) { cubbyhole.put(i); System.out.println("Producer #" + this.number + " put: " + i); try { sleep((int)(Math.random() * 100)); } catch (InterruptedException e) { } } } }
結果
上麵的代碼示例將產生以下結果。
Producer #1 put: 0 Consumer #1 got: 0 Producer #1 put: 1 Consumer #1 got: 1 Producer #1 put: 2 Consumer #1 got: 2 Producer #1 put: 3 Consumer #1 got: 3 Producer #1 put: 4 Consumer #1 got: 4 Producer #1 put: 5 Consumer #1 got: 5 Producer #1 put: 6 Consumer #1 got: 6 Producer #1 put: 7 Consumer #1 got: 7 Producer #1 put: 8 Consumer #1 got: 8 Producer #1 put: 9 Consumer #1 got: 9