正如其他人已经提到的那样，CyclicBarrier并不是完全适合该任务的最佳工具。
我也同意，解决方案是将线程链接在一起，并始终让一个线程设置下一个线程。
这是使用信号量的实现：
import java.util.concurrent.BrokenBarrierException; import java.util.concurrent.Semaphore;public class PrintNumbersWithSemaphore implements Runnable {private final Semaphore previous;private final Semaphore next;private final int[] numbers;public PrintNumbersWithSemaphore(Semaphore previous, Semaphore next, int[] numbers) { this.previous = previous; this.next = next; this.numbers = numbers;}@Overridepublic void run() { for (int i = 0; i < numbers.length; i++) { wait4Green(); System.out.println(numbers[i]); switchGreen4Next(); }}private void switchGreen4Next() { next.release();}private void wait4Green() { try { previous.acquire(); } catch (InterruptedException e) { e.printStackTrace(); throw new RuntimeException(e); }}static public void main(String argv[]) throws InterruptedException, BrokenBarrierException { Semaphore sem1 = new Semaphore(1); Semaphore sem2 = new Semaphore(1); Semaphore sem3 = new Semaphore(1); sem1.acquire(); sem2.acquire(); sem3.acquire(); Thread t1 = new Thread(new PrintNumbersWithSemaphore(sem3, sem1, new int[] { 1, 4, 7 })); Thread t2 = new Thread(new PrintNumbersWithSemaphore(sem1, sem2, new int[] { 2, 5, 8 })); Thread t3 = new Thread(new PrintNumbersWithSemaphore(sem2, sem3, new int[] { 3, 6, 9 })); t1.start(); t2.start(); t3.start(); sem3.release(); t1.join(); t2.join(); t3.join();}}在我看来，使用CyclicBarrier实现起来非常麻烦：
import java.util.concurrent.BrokenBarrierException; import java.util.concurrent.CyclicBarrier;public class PrintNumbersWithCyclicBarrier implements Runnable {private final CyclicBarrier previous;private final CyclicBarrier next;private final int[] numbers;public PrintNumbersWithCyclicBarrier(CyclicBarrier previous, CyclicBarrier next, int[] numbers) { this.previous = previous; this.next = next; this.numbers = numbers;}@Overridepublic void run() { for (int i = 0; i < numbers.length; i++) { wait4Green(); System.out.println(numbers[i]); switchRed4Myself(); switchGreen4Next(); }}private void switchGreen4Next() { try { next.await(); } catch (Exception e) { e.printStackTrace(); throw new RuntimeException(e); }}private void switchRed4Myself() { previous.reset();}private void wait4Green() { try { previous.await(); } catch (Exception e) { e.printStackTrace(); throw new RuntimeException(e); }}static public void main(String argv[]) throws InterruptedException, BrokenBarrierException { CyclicBarrier cb1 = new CyclicBarrier(2); CyclicBarrier cb2 = new CyclicBarrier(2); CyclicBarrier cb3 = new CyclicBarrier(2); Thread t1 = new Thread(new PrintNumbersWithCyclicBarrier(cb3, cb1, new int[] { 1, 4, 7 })); Thread t2 = new Thread(new PrintNumbersWithCyclicBarrier(cb1, cb2, new int[] { 2, 5, 8 })); Thread t3 = new Thread(new PrintNumbersWithCyclicBarrier(cb2, cb3, new int[] { 3, 6, 9 })); t1.start(); t2.start(); t3.start(); cb3.await(); t1.join(); t2.join(); t3.join();}}
