Java 并发中 CountDownLatch 和 CyclicBarrier 的区别
javaserver side programmingprogramming
CountDownLatch 和 CyclicBarrier 都用于多线程环境，它们都是其中的一部分。
根据 Java Doc −
CountDownLatch − 一种同步辅助，允许一个或多个线程等待，直到其他线程中正在执行的一组操作完成。
CyclicBarrier − 一种同步辅助，允许一组线程全部等待彼此到达公共屏障点。
| Sr.否。 | Key | CyclicBarrier | CountDownLatch |
|---|---|---|---|
| 1 | Basic | 一种同步辅助，允许一组线程全部等待彼此到达公共屏障点。 | 一种同步辅助，允许一个或多个线程等待，直到其他线程中正在执行的一组操作完成。 |
| 2 | Ruunable | 它有一个构造函数，可以在其中提供 Runnable。 | 它没有这样的构造函数 |
| 3 | Thread /Task | 它维护线程数 | 它维护任务数 |
| 4. | 可前进 | 不可前进 | 可前进。 |
| 5 | 异常 | 如果一个线程在等待时被中断，则所有其他等待线程将抛出 B rokenBarrierException | 只有当前线程将抛出 InterruptedException。它不会影响其他线程 |
CyclicBarrier 示例
public class Main {
public static void main(String args[]) throws InterruptedException {
ExecutorService executors = Executors.newFixedThreadPool(4);
CyclicBarrier cyclicBarrier = new CyclicBarrier(5);
executors.submit(new Service1(cyclicBarrier));
executors.submit(new Service1(cyclicBarrier));
executors.submit(new Service2(cyclicBarrier));
executors.submit(new Service2(cyclicBarrier));
executors.submit(new Service2(cyclicBarrier));
Thread.sleep(3000);
System.out.println("Done");
}
}
import java.util.concurrent.BrokenBarrierException;
import java.util.concurrent.CyclicBarrier;
public class Service1 implements Runnable {
CyclicBarrier cyclicBarrier;
public Service1(CyclicBarrier cyclicBarrier) {
super();
this.cyclicBarrier = cyclicBarrier;
}
@Override
public void run() {
System.out.println("Services1" + cyclicBarrier.getNumberWaiting());
while (true) {
try {
cyclicBarrier.await();
} catch (InterruptedException | BrokenBarrierException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
import java.util.concurrent.BrokenBarrierException;
import java.util.concurrent.CyclicBarrier;
public class Service2 implements Runnable {
CyclicBarrier cyclicBarrier;
public Service2(CyclicBarrier cyclicBarrier) {
super();
this.cyclicBarrier = cyclicBarrier;
}
@Override
public void run() {
System.out.println("Services2" + cyclicBarrier.getNumberWaiting());
while (true) {
try {
cyclicBarrier.await();
} catch (InterruptedException | BrokenBarrierException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
CountDownLatch 示例
public class Main {
public static void main(String args[]) throws InterruptedException {
ExecutorService executors = Executors.newFixedThreadPool(4);
CountDownLatch latch= new CountDownLatch(2);
executors.submit(new Service1(latch));
executors.submit(new Service2(latch));
latch.await();
System.out.println("Done");
}
}
import java.util.concurrent.CountDownLatch;
public class Service1 implements Runnable {
CountDownLatch latch;
public Service1(CountDownLatch latch) {
super();
this.latch = latch;
}
@Override
public void run() {
try {
Thread.sleep(20000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
latch.countDown();
System.out.println("Services2"+latch.getCount());
}
}
import java.util.concurrent.CountDownLatch;
public class Service2 implements Runnable {
CountDownLatch latch;
public Service2(CountDownLatch latch) {
super();
this.latch = latch;
}
@Override
public void run() {
try {
Thread.sleep(20000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
latch.countDown();
System.out.println("Services2"+latch.getCount());
}
}
