ForkJoinDemo

package com.example.fj;

import java.util.concurrent.ExecutionException;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.ForkJoinTask;
import java.util.concurrent.RecursiveTask;

/**
 * @ClassName ForkJoinDemo
 * @description: TODO
 * @author: went
 * @Date 2021/7/15 9:48 上午
 **/
public class ForkJoinDemo {

    public static void main(String[] args) throws ExecutionException, InterruptedException {

        ForkJoinPool pool = new ForkJoinPool();

        final MyTask myTask = new MyTask(1, 100);

        final ForkJoinTask<Integer> submit = pool.submit(myTask);

        final Integer result = submit.get();

        System.out.println(result);

    }
}


class MyTask extends RecursiveTask<Integer> {

    private int begin;

    private int end;

    private int result;

    public MyTask(int begin, int end) {
        this.begin = begin;
        this.end = end;
    }

    @Override
    protected Integer compute() {

        if (end - begin > 10) {
            // 继续拆
            Integer mid = (end + begin)/2;

            MyTask left = new MyTask(begin, mid);
            MyTask right = new MyTask(mid+1, end);
            left.fork();
            right.fork();
            result = left.join() + right.join();
        } else {
            // 直接算
            for (int i = begin; i <= end ; i++) {
                result += i;
            }
            System.out.println(Thread.currentThread().getName() + " 计算结果：" + result);
        }

        return result;
    }
}