Java並列プログラミングにおけるStream並列処理の使用法とパフォーマンス

import java.util.Arrays;
import java.util.stream.IntStream;

public class StreamParallel {

    public static void main(String[] args) {
        int[] numbers = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};

        // 按顺序处理数字
        int sum = IntStream.of(numbers).sum();
        System.out.println("顺序求和结果：" + sum);

        // 并行处理数字
        sum = IntStream.of(numbers).parallel().sum();
        System.out.println("并行求和结果：" + sum);
    }
}

import java.awt.image.BufferedImage;
import java.util.stream.IntStream;
import java.util.stream.Stream;

// 将图像灰度化
public class ImageGrayscale {

    public static BufferedImage grayscale(BufferedImage image) {
        int width = image.getWidth();
        int height = image.getHeight();

        // 以并行方式将每个像素灰度化
        int[] grayPixels = Stream.generate(() -> 0).limit(width * height)
                .parallel()
                .mapToInt(i -> {
                    int x = i % width;
                    int y = i / width;
                    int color = image.getRGB(x, y);
                    return (color & 0xff) * 255 / (255 * 3);
                })
                .toArray();

        // 创建灰度图像
        BufferedImage grayImage = new BufferedImage(width, height, BufferedImage.TYPE_BYTE_GRAY);
        grayImage.setRGB(0, 0, width, height, grayPixels, 0, width);
        return grayImage;
    }
}