CyclicBarrier 用法 ，汇总统计

package net.biancheng.c.thread;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.BrokenBarrierException;
import java.util.concurrent.CyclicBarrier;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.locks.ReentrantLock;

/**
 * @author cheng
 * @Description 统计所有线程的数字汇总
 * @Date 2022/8/29 17:29
 */
public class Caculate {
    public static  List list = new ArrayList();

    public static void main(String[] args) {
        int nums = 15;
        ExecutorService executor = Executors.newFixedThreadPool(nums);
        CyclicBarrier barrier = new CyclicBarrier(nums, () -> {
            try {
                System.out.println("Arrays.toString(list.toArray()) = " + Arrays.toString(list.toArray()));
                Integer total = 0;
                for (int i = 0; i < list.size(); i++) {
                    total = total + list.get(i);
                }
                System.out.println("total = " + total);

            } catch (Exception e) {
                e.printStackTrace();
            }

        });

        for (int i = 0; i < nums; i++) {
            executor.submit(new Each(barrier, (i + 1)));
        }

        executor.shutdown();
    }

    static class Each implements Runnable {
        private CyclicBarrier barrier;
        private Integer nums;
        private static final ReentrantLock lock = new ReentrantLock();

        public Each(CyclicBarrier barrier, Integer nums) {
            this.barrier = barrier;
            this.nums = nums;
        }

        @Override
        public String toString() {
            return "Each{" +
                    "barrier=" + barrier +
                    ", nums=" + nums +
                    '}';
        }

        @Override
        public void run() {

            try {
                //必须同步,不然nums可能为空;
              /*  synchronized(Each.class){
                    list.add(nums);
                }*/
                lock.lock();
                list.add(nums);
                lock.unlock();
                System.out.println(Thread.currentThread().getName() + ",nums = " + nums);
                barrier.await();
            } catch (InterruptedException e) {
                e.printStackTrace();
            } catch (BrokenBarrierException e) {
                e.printStackTrace();
            }
        }
    }

}