Java并发工具类LockSupport

LockSupport

J.U.C框架中有一个叫做LockSupport的类，可以精准地阻塞和唤醒特定的线程，并作为其他同步类的原语。 LockSupport包含一个park(Object blocker)和unpark(Object blocker)方法，分别用于阻塞和唤醒。

举个例子，下面的代码包含一个线程thread1和主线程，在thread1中调用park方法，在主线程中调用unpark，然后打印thread1的状态：

import java.util.concurrent.locks.LockSupport;{(String[] args) throws InterruptedException {Thread thread1 = new Thread(new Runnable() {() {System.out.println(“thread 1 start”);LockSupport.park(Thread.currentThread());try {Thread.sleep(4000);} catch (InterruptedException e) {e.printStackTrace();}System.out.println(“thread 1 end”);}});thread1.start();System.out.println(“main thread start,thread1 “+thread1.getState());Thread.sleep(2000);System.out.println(“main thread running,thread1 “+thread1.getState());LockSupport.unpark(thread1);Thread.sleep(6000);System.out.println(“main thread end,thread1 “+thread1.getState());}}

执行结果：

thread 1 start main thread start,thread1 RUNNABLE main thread running,thread1 WAITING thread 1 end main thread end,thread1 TERMINATED

可以看到，park之后thread1变成WAITTING，，unpark之后唤醒继续执行直到结束

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