我們先來(lái)看一下實(shí)例代碼：
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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 { // 啟動(dòng)“線(xiàn)程t1” system.out.println(thread.currentthread().getname()+" start t1"); t1.start(); // 主線(xiàn)程等待t1通過(guò)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(xiàn)程鎖住了，t1.wait()的時(shí)候，讓當(dāng)前線(xiàn)程等待，其實(shí)是讓main線(xiàn)程等待了，然后釋放了t1鎖，t1線(xiàn)程執(zhí)行，打印t1 call notify()，然后喚醒main線(xiàn)程，最后結(jié)束；
這里說(shuō)一下wait()與sleep()的區(qū)別，他們的共同點(diǎn)都是讓線(xiàn)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)；
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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整除時(shí)，休眠100毫秒 if (i%4 == 0) thread.sleep(100); } } catch (interruptedexception e) { e.printstacktrace(); } } } } } |
