- Java code
class Storage{ public int i = 0;}class Counter implements Runnable{ private Storage storage; public Counter(Storage s) { storage = s; } public void run() { try { Thread.sleep(100); } catch(Exception e) { System.out.println(e); } for(int i = 0; i != 100; ++i) { synchronized(storage) { storage.i = i; System.out.println("counter: " +storage.i); storage.notify(); } } }}class Printer implements Runnable{ private Storage storage; public Printer(Storage s) { storage = s; } public void run() { for(int i = 0; i != 100; ++i) { synchronized(storage) { try { storage.wait(); } catch(Exception e) { System.out.println(e); } System.out.println("printer: " +storage.i); } } }}public class TestThread{ public static void main(String[] argv) { Storage s = new Storage(); Thread counter = new Thread(new Counter(s)); Thread printer = new Thread(new Printer(s)); printer.start(); counter.start(); }}打印结果是：
counter: 0
.
.
.
counter: 97
counter: 98
counter: 99
printer: 99
然后就卡在这里了。
代码有问题吗？没发现，求高手们指点下
------解决方案--------------------
Printer 里的storage 调用了Object的wait();调用之后没有被唤醒，需要加上storage.notify();才可以继续执行。
void wait()
Causes current thread to wait until another thread invokes the notify() method or the notifyAll() method for this object.
//api 文档解释，没有被唤醒，就一直睡在那，肯定不执行了。到99的时候其实第一个进程就执行完了。
------解决方案--------------------
- Java code
class Storage { public int i = 0; boolean isWaiting=false;//是否已在等待}class Counter implements Runnable{ private Storage storage; public Counter(Storage s) { storage = s; } public void run() { for(int i = 0; i != 100; ++i) { synchronized(storage) { //没有消费者等待，则不创建数据 if(!storage.isWaiting){ i--; continue; } storage.i=i; System.out.println("counter: " +storage.i); storage.notify();//通知消费者去取该数据 try { storage.wait();//等待消费者去使用数据 } catch (InterruptedException e) { e.printStackTrace(); } } } }}class Printer implements Runnable{ private Storage storage; public Printer(Storage s) { storage = s; } public void run() { for(int i = 0; i != 100; ++i) { synchronized(storage) { try { storage.isWaiting=true;//必须要先等待 storage.wait();//等待生产者去创建数据 } catch(Exception e) { System.out.println(e); } System.out.println("printer: " +storage.i); storage.notify();//通知生产者去创建数据 } } }}public class TestThread{ public static void main(String[] argv) { Storage s = new Storage(); Thread counter = new Thread(new Counter(s)); Thread printer = new Thread(new Printer(s)); printer.start(); counter.start(); }}