ForkJoin

ForkJoin

什么是ForkJoin？

并行执行任务，提交效率，大数据量的时候使用！

把大任务拆分成小任务

ForkJoin特点：工作窃取

内部维护的双端队列，两端都可以出

如何使用

1. 创建ForkJoinPool对象
2. 新建一个计算任务ForkJoinTask放入池子中计算

package com.lizhi;

import java.util.concurrent.RecursiveTask;

public class ForkJoinDemo extends RecursiveTask<Long> {
    private long start;
    private long end;
    private long temp = 10000L;

    public ForkJoinDemo(long start, long end) {
        this.start = start;
        this.end = end;
    }

    @Override
    public Long compute(){
        long result = 0;
        if(end-start<temp){
            for (long i = start; i <= end; i++) {
                result+=i;
            }
        }else {
            long middle = (start + end) / 2;
            ForkJoinDemo forkJoinDemo1 = new ForkJoinDemo(start,middle);
            forkJoinDemo1.fork();
            ForkJoinDemo forkJoinDemo2 = new ForkJoinDemo(middle,end);
            forkJoinDemo2.fork();//把任务压入线程队列
            result = forkJoinDemo1.join()+ forkJoinDemo2.join();
        }
        return result;
    }
}