简介
CountDownLatch是线程挨个执行，直到全部完成一组线程的任务。CycliBarrier是线程之间会互相等待，到屏障的时候然后再一起执行任务。
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import java.util.concurrent.BrokenBarrierException;
import java.util.concurrent.CyclicBarrier;
public class CyclicBarrierExample {
public static void main(String[] args) {
// 创建一个 CyclicBarrier，当 3 个线程都到达屏障时执行指定的动作
CyclicBarrier cyclicBarrier = new CyclicBarrier(3, () -> {
System.out.println("所有线程都已到达屏障，开始下一阶段工作！");
});
// 创建并启动 3 个线程
new Thread(new Task(cyclicBarrier, 1)).start();
new Thread(new Task(cyclicBarrier, 2)).start();
new Thread(new Task(cyclicBarrier, 3)).start();
}
static class Task implements Runnable {
private CyclicBarrier cyclicBarrier;
private int threadId;
public Task(CyclicBarrier cyclicBarrier, int threadId) {
this.cyclicBarrier = cyclicBarrier;
this.threadId = threadId;
}
@Override
public void run() {
try {
System.out.println("线程 " + threadId + " 正在执行任务...");
Thread.sleep(threadId * 1000);
System.out.println("线程 " + threadId + " 完成任务，等待其他线程到达屏障...");
cyclicBarrier.await();
System.out.println("线程 " + threadId + " 继续执行下一阶段任务...");
} catch (InterruptedException | BrokenBarrierException e) {
e.printStackTrace();
}
}
}
}
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import java.util.concurrent.CountDownLatch;
public class CountDownLatchExample {
public static void main(String[] args) throws InterruptedException {
// 创建一个初始计数值为 3 的 CountDownLatch
CountDownLatch countDownLatch = new CountDownLatch(3);
// 创建并启动 3 个工作线程
new Thread(new Worker(countDownLatch, "Worker 1")).start();
new Thread(new Worker(countDownLatch, "Worker 2")).start();
new Thread(new Worker(countDownLatch, "Worker 3")).start();
// 主线程等待 CountDownLatch 的计数值变为 0
countDownLatch.await();
System.out.println("所有工作线程都已完成任务，主线程继续执行。");
}
static class Worker implements Runnable {
private CountDownLatch countDownLatch;
private String name;
public Worker(CountDownLatch countDownLatch, String name) {
this.countDownLatch = countDownLatch;
this.name = name;
}
@Override
public void run() {
try {
System.out.println(name + " 正在执行任务...");
Thread.sleep(1000);
System.out.println(name + " 完成任务，进行倒计时。");
countDownLatch.countDown();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
CountDownLatch也是可以线程CyclicBarrier.
