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最新推荐文章于 2024-09-03 14:04:00 发布

chengxu2011

最新推荐文章于 2024-09-03 14:04:00 发布

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分类专栏： java

本文链接：https://blog.youkuaiyun.com/chengxu2011/article/details/51192018

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本文介绍了一个使用Java实现的并行计算示例，通过Fork/Join框架分解任务为子任务并利用多核CPU进行高效计算。该示例计算了一组整数的总和，展示了如何创建自定义RecursiveTask子类来实现并行处理。

import java.util.List;
import java.util.concurrent.RecursiveTask;


public class MyCounter extends RecursiveTask<Integer> {

	private static final long serialVersionUID = 1L;
	
	private List<Integer> list;

	/**
	 * 开始
	 */
	private int first;

	/**
	 * 结束
	 */
	private int last;

	public MyCounter(int first, int last, List<Integer> list) {
		super();
		this.first = first;
		this.last = last;
		this.list =list;
	}



	@Override
	protected Integer compute() {

		int sum = 0;

		if (last - first < 10) {
			System.out.print("["+first+"-"+last+"]");
			for (int i = first; i < last; i++) {
				sum = sum + list.get(i);
			}
		} else {
			int middle = (last + first)/2;
			MyCounter left = new MyCounter(first, middle, list);
			MyCounter right = new MyCounter(middle, last, list);
			left.fork();
			right.fork();
			sum = left.join()+right.join();
			System.out.println(sum);
		}
		return sum;
	}

}

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.Future;

public class MyTest {
	public static void main(String[] args) throws InterruptedException,
			ExecutionException {
		List<Integer> list = new ArrayList<>();
		for (int i = 0; i < 20; i++) {
			list.add(i);
		}

		System.out.println(list);

		ForkJoinPool forkJoinPool = new ForkJoinPool();// 对线程池的扩展
		Future<Integer> result = forkJoinPool
				.submit(new MyCounter(0, 20, list));

		System.out.println(result.get());
		forkJoinPool.shutdown();
	}
}