package concurrent;import java.util.Random;import java.util.concurrent.*;/** * Auth: zhouhongliang * Date：2019/8/1 * 分配多个线程共同执行某个任务，等待子线程都结束，主线程才结束 */public class CallableDemo { public static void main(String[] args) throws ExecutionException, InterruptedException { ExecutorService executorService = Executors.newFixedThreadPool(3); CountDownLatch countDownLatch = new CountDownLatch(3); Future<Integer> future1 = executorService.submit(new CallableTask(countDownLatch)); Future<Integer> future2 = executorService.submit(new CallableTask(countDownLatch)); Future<Integer> future3 = executorService.submit(new CallableTask(countDownLatch)); System.out.println(future1.get()); System.out.println(future2.get()); System.out.println(future3.get()); countDownLatch.await(); executorService.shutdown(); }}class CallableTask implements Callable<Integer>{ private CountDownLatch countDownLatch; public CallableTask(CountDownLatch countDownLatch) { this.countDownLatch = countDownLatch; } @Override public Integer call() throws Exception { int count = 0; final int random = new Random().nextInt(1000); for (int i=0;i<random;i++){ count ++; } countDownLatch.countDown(); return count; }}