我们先来看一下实例代码：
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class threada extends thread{
public threada(string name) { super (name); }
public void run() { synchronized ( this ) { system.out.println(thread.currentthread().getname()+ " call notify()" ); notify(); } } } public class waittest { public static void main(string[] args) { threada t1 = new threada( "t1" ); synchronized (t1) { try { // 启动[线程t1] system.out.println(thread.currentthread().getname()+ " start t1" ); t1.start();
// 主线程等待t1通过notify()唤醒。 system.out.println(thread.currentthread().getname()+ " wait()" ); t1.wait();
system.out.println(thread.currentthread().getname()+ " continue" ); } catch (interruptedexception e) { e.printstacktrace(); } } } } |
输出结果：main start t1 -> main wait() -> t1 call notify() -> main continue
其实调用t1.start()，t1为就绪状态，只是main方法中，t1被main线程锁住了，t1.wait()的时候，让当前线程等待，其实是让main线程等待了，然后释放了t1锁，t1线程执行，打印t1 call notify()，然后唤醒main线程，最后结束；
这里说一下wait()与sleep()的区别，他们的共同点都是让线程休眠，但是wait()会释放对象同步锁，而sleep()不会；下面的代码t1结束之后才会运行t2；能够证实这一点；
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public class sleeplocktest{ private static object obj = new object(); public static void main(string[] args){ threada t1 = new threada( "t1" ); threada t2 = new threada( "t2" ); t1.start(); t2.start(); } static class threada extends thread{ public threada(string name){ super (name); } public void run(){ synchronized (obj) { try { for ( int i= 0 ; i < 10 ; i++){ system.out.printf( "%s: %d\n" , this .getname(), i); // i能被4整除时，休眠100毫秒 if (i% 4 == 0 ) thread.sleep( 100 ); } } catch (interruptedexception e) { e.printstacktrace(); } } } } } |
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