ForkJoinTask多线程分段计算结果并且汇总结果

鹏_鹏

于 2019-10-06 10:40:12 发布

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CC 4.0 BY-SA版权

文章标签：多线程处理

本文链接：https://blog.youkuaiyun.com/qq_21000751/article/details/102213885

本文介绍了一个使用Java的ForkJoinPool实现的并行计算任务分解与合并的示例。通过定义一个继承自RecursiveTask的MyTask类，实现了对指定范围内的整数求和。当待处理的数据量超过设定阈值时，任务将被拆分为两个子任务并行执行，最终汇总结果。

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

class MyTask extends RecursiveTask<Integer> {
    public static final int ADJUST_VALUE = 10;
    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() {
        System.out.println("begin:"+begin+",end:"+end);
        if ((end - begin) <= ADJUST_VALUE){
            for (int i = begin; i <= end; i++) {
                result = result + i;
            }
        }else {
            int mid = (begin + end) / 2;
            MyTask myTask1 = new MyTask(begin,mid);
            MyTask myTask2 = new MyTask(mid +1,end);
            myTask1.fork();
            myTask2.fork();
            result = myTask1.join() + myTask2.join();
        }
        return result;
    }
}

public class ForkJoinTaskDemo {

    public static void main(String[] args) throws ExecutionException, InterruptedException {
        MyTask myTask = new MyTask(0,100);
        ForkJoinPool forkJoinPool = new ForkJoinPool();
        ForkJoinTask<Integer> forkJoinTask = forkJoinPool.submit(myTask);
        System.out.println(forkJoinTask.get());
        forkJoinPool.shutdown();
    }
}