利用Condition来实现多线程交替打印ABC

【利用Condition来实现多线程交替打印ABC】使用重入锁 ReentrantLock先来获得,.newCondition对象,Condition 可以用来指定队列,唤醒指定队列中的线程,这样在多线程环境下会有更高的效率;
利用Condition来实现多线程交替打印ABC
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package morning; import java.util.concurrent.locks.Condition; import java.util.concurrent.locks.Lock; import java.util.concurrent.locks.ReentrantLock; //4.三个线程交替输出A B C ,输出20遍。 public class Lock_Condition_ABC { private static Lock lock = new ReentrantLock(); private static Condition A = lock.newCondition(); private static Condition B = lock.newCondition(); private static Condition C = lock.newCondition(); private static int count = 0; privatestatic int sum=1; static class ThreadA extends Thread { @Override public void run() { try { lock.lock(); for (int i = 0; i < 10; i++) { while (count % 3 != 0){//注意这里是不等于0,也就是说没轮到该线程执行,之前一直等待状态 A.await(); //该线程A将会释放lock锁,构造成节点加入等待队列并进入等待状态 } System.out.println("-------第"+sum+"次--------"); System.out.println("A"); count++; B.signal(); // A执行完唤醒B线程 }} catch (InterruptedException e) { e.printStackTrace(); } finally { lock.unlock(); } } }static class ThreadB extends Thread { @Override public void run() { try { lock.lock(); for (int i = 0; i < 10; i++) { while (count % 3 != 1) B.await(); // B释放lock锁,当前面A线程执行后会通过B.signal()唤醒该线程 System.out.println("B"); count++; C.signal(); // B执行完唤醒C线程 } } catch (InterruptedException e) { e.printStackTrace(); } finally { lock.unlock(); } } }static class ThreadC extends Thread { @Override public void run() { try { lock.lock(); for (int i = 0; i < 10; i++) { while (count % 3 != 2) C.await(); // C释放lock锁 System.out.println("C"); count++; sum++; A.signal(); // C执行完唤醒A线程 } } catch (InterruptedException e) { e.printStackTrace(); } finally { lock.unlock(); } } }public static void main(String[] args) throws InterruptedException { new ThreadA().start(); new ThreadB().start(); new ThreadC().start(); } }

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