RecursiveTask的使用-优快云博客

本文链接：https://blog.youkuaiyun.com/qq_20004115/article/details/103164835

本文深入探讨了Java中的Fork/Join框架，并通过具体实例展示了如何利用该框架进行高效的并行计算。通过递归任务划分与合并，实现对大量数据的快速求和运算。

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package com.example.sina.thread;

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

public class RecursiveTest {
// 定义最小区间为10
private final static int MAX_THRESHOLD = 100;

public static void main(String[] args) {
final ForkJoinPool forkJoinPool = new ForkJoinPool();
ForkJoinTask<Integer> future = forkJoinPool.submit(new CalculateRecursiveTask(1, 1000));
try {
Integer result = future.get();
System.out.println(result);
} catch (InterruptedException | ExecutionException e) {
e.printStackTrace();
}
}

private static class CalculateRecursiveTask extends RecursiveTask<Integer> {

       private static final long serialVersionUID = 1L;
       // 起始
private int start;
// 结束
private int end;

public CalculateRecursiveTask(int start, int end) {
this.start = start;
this.end = end;
}

@Override
protected Integer compute() {
// 如果起始和结束范围小于我们定义的区间范围，则直接计算
if ((end - start) <= MAX_THRESHOLD) {
return IntStream.rangeClosed(start, end).sum();

} else {
// 否则，将范围一分为二，分成两个子任务
int middle = (start + end) / 2;
CalculateRecursiveTask leftTask = new CalculateRecursiveTask(start, middle);
CalculateRecursiveTask rightTask = new CalculateRecursiveTask(middle + 1, end);
// 执行子任务
leftTask.fork();
rightTask.fork();

// 汇总子任务
return leftTask.join() + rightTask.join();
}
}
}
}