java 多线程 线程池：多核CPU利用ExecutorService newWorkStealingPool； ForkJoinPool线程池 执行可拆分的任务RecursiveAction

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * @ClassName ExecutorsWorkStealingPoolTest
 * @projectName: object1
 * @author: Zhangmingda
 * @description： XXX
 * date: 2021/4/27.
 */
public class ExecutorsWorkStealingPoolTest {
    public static void main(String[] args) throws InterruptedException {
        Runnable r = () -> {
            String tName = Thread.currentThread().getName();
            try {
                System.out.println(tName + "开始运行");
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println(tName + "运行结束");
        };
        /**
         * 创建支持多核CPU并行的线程池
         */
        ExecutorService executorService = Executors.newWorkStealingPool(); //译文：Stealing 窃取
        for (int i=0; i<10; i++){
            executorService.submit(r);
        }
        System.out.println(Runtime.getRuntime().availableProcessors()); //CPU核心数
        Thread.sleep(3000);
    }
}

import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.RecursiveAction;
import java.util.concurrent.TimeUnit;

/**
 * @ClassName MyRecursiveAction
 * @projectName: object1
 * @author: Zhangmingda
 * @description： XXX
 * date: 2021/4/27.
 */
public class MyRecursiveAction {
    /**
     * 定义一个支持拆分计算的任务
     */
    private static class PrintTaskRecursiveAction extends RecursiveAction{
        private int start;
        private int end;
        private final int MAXNUM = 100;

        /**
         * 构造实例传入任务需要的参数
         */
        public PrintTaskRecursiveAction(int start, int end) {
            this.start = start;
            this.end = end;
        }

        /**
         * 具体执行计算的任务的抽象方法重写
         */
        @Override
        protected void compute() {
            String tName = Thread.currentThread().getName();
            if ((end - start) < MAXNUM){
                System.out.println(tName + "    start:" + start);
                System.out.println(tName + "    end:" + end);
            }else {
                int middle = (start + end) /2;
                /**
                 * 大任务拆分为两个小任务，
                 */
                PrintTaskRecursiveAction subTask1 = new PrintTaskRecursiveAction(start,middle);
                PrintTaskRecursiveAction subTask2 = new PrintTaskRecursiveAction(middle,end);
                //分别执行两个小任务
                subTask1.fork();subTask2.fork();
            }
        }
    }

    /**
     执行计算任务
     */
    public static void main(String[] args) throws InterruptedException {
        ForkJoinPool forkJoinPool = new ForkJoinPool();
        PrintTaskRecursiveAction printTask = new PrintTaskRecursiveAction(1,300);
        //线程池提交任务
        forkJoinPool.submit(printTask);
        forkJoinPool.awaitTermination(1, TimeUnit.SECONDS);
        //关闭提交接口
        forkJoinPool.shutdown();
    }
}