CountDownLatch等别人做完再继续适合场景主线程等多个任务都完成后再做汇总。import java.util.concurrent.CountDownLatch; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; public class CountDownLatchDemo { public static void main(String[] args) throws InterruptedException { int taskCount 3; CountDownLatch latch new CountDownLatch(taskCount); try (ExecutorService executor Executors.newVirtualThreadPerTaskExecutor()) { for (int i 1; i taskCount; i) { int taskId i; executor.submit(() - { try { System.out.println(任务 taskId 开始执行); Thread.sleep(1000L * taskId); System.out.println(任务 taskId 执行完成); } catch (InterruptedException e) { Thread.currentThread().interrupt(); } finally { latch.countDown(); } }); } System.out.println(主线程等待所有任务完成...); latch.await(); System.out.println(所有任务都完成了主线程继续执行); } } }核心记法latch.countDown(); // 完成一个计数减 1 latch.await(); // 等计数变成 0CyclicBarrier大家到齐再一起继续适合场景多个线程都准备好以后再同时进入下一阶段。import java.util.concurrent.CyclicBarrier; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; public class CyclicBarrierDemo { public static void main(String[] args) { int workerCount 3; CyclicBarrier barrier new CyclicBarrier(workerCount, () - { System.out.println(所有线程都到达栅栏开始下一阶段); }); try (ExecutorService executor Executors.newVirtualThreadPerTaskExecutor()) { for (int i 1; i workerCount; i) { int workerId i; executor.submit(() - { try { System.out.println(线程 workerId 正在准备); Thread.sleep(1000L * workerId); System.out.println(线程 workerId 到达栅栏); barrier.await(); System.out.println(线程 workerId 继续执行后续任务); } catch (Exception e) { e.printStackTrace(); } }); } } } }核心记法barrier.await(); // 到栅栏这里等直到指定数量的线程都到齐一句话区别CountDownLatch一个线程等多个线程完成。 CyclicBarrier多个线程互相等大家到齐再一起走。CountDownLatch一般是一次性的CyclicBarrier可以循环复用所以名字里有Cyclic。