CyclicBarrier

public class Test5 {

       private  static  Random random = new Random();

       public static void main(String[] args) {
        //数组大小
        int size = 50000;
        //定义数组
        int[] numbers = new int[size];
        //随机初始化数组
        for (int i = 0; i < size; i++) {
            numbers[i] = random.nextInt(100);
        }

        //单线程计算结果
        System.out.println();
        Long sum = 0L;
        for (int i = 0; i < size; i++) {
            sum += numbers[i];
        }
        System.out.println("单线程计算结果：" + sum);

        //多线程计算结果
        //定义线程池
        ExecutorService executorService = Executors.newFixedThreadPool(5);
        //定义长度为5的数组保存每个线程的计算结果
        final int[] results = new int[5];
        //定义一个大小为5的循环栅栏
        CyclicBarrier barrier = new CyclicBarrier(5, () -> {
            long sums = 0;
            for (int i = 0; i < 5; i++) {
                sums += results[i];
            }
            System.out.println("多线程计算结果：" + sums);
        });

        //子数组长度
        int length = 10000;
        //定义五个线程去计算
        for (int i = 0; i < 5; i++) {
            //定义子数组
            int[] subNumbers = Arrays.copyOfRange(numbers, (i * length), ((i + 1) * length));
            //盛放计算结果
            int finalI = i;
            executorService.submit(() -> {
                for (int j = 0; j < subNumbers.length; j++) {
                    results[finalI] += subNumbers[j];
                }
                //等待其他线程进行计算
                try {
                    barrier.await();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                } catch (BrokenBarrierException e) {
                    e.printStackTrace();
                }
            });
        }
        //关闭线程池
        executorService.shutdown();
    }

}