我們先來看一下實(shí)例代碼：
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 { // 啟動(dòng)“線程t1” System.out.println(Thread.currentThread().getName()+" start t1"); t1.start(); // 主線程等待t1通過notify()喚醒。 System.out.println(Thread.currentThread().getName()+" wait()"); t1.wait(); System.out.println(Thread.currentThread().getName()+" continue"); } catch (InterruptedException e) { e.printStackTrace(); } } }}輸出結(jié)果：main start t1 -> main wait() -> t1 call notify() -> main continue
其實(shí)調(diào)用t1.start()，t1為就緒狀態(tài)，只是main方法中，t1被main線程鎖住了，t1.wait()的時(shí)候，讓當(dāng)前線程等待，其實(shí)是讓main線程等待了，然后釋放了t1鎖，t1線程執(zhí)行，打印t1 call notify()，然后喚醒main線程，最后結(jié)束；
這里說一下wait()與sleep()的區(qū)別，他們的共同點(diǎn)都是讓線程休眠，但是wait()會(huì)釋放對(duì)象同步鎖，而sleep()不會(huì)；下面的代碼t1結(jié)束之后才會(huì)運(yùn)行t2；能夠證實(shí)這一點(diǎn)；
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整除時(shí)，休眠100毫秒 if (i%4 == 0) Thread.sleep(100); } } catch (InterruptedException e) { e.printStackTrace(); } } } } }新聞熱點(diǎn)
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