Java函数式编程中并行计算的优势与局限

import java.util.stream.IntStream;

public class ParallelSum {

    // 串行计算
    public static int sumSequential(int[] numbers) {
        int sum = 0;
        for (int number : numbers) {
            sum += number;
        }
        return sum;
    }

    // 并行计算
    public static int sumParallel(int[] numbers) {
        return IntStream.of(numbers).parallel().sum();
    }

    public static void main(String[] args) {
        int[] numbers = new int[1000000];
        for (int i = 0; i < numbers.length; i++) {
            numbers[i] = i;
        }

        // 测量串行计算的时间
        long startTime = System.nanoTime();
        int sumSequential = sumSequential(numbers);
        long endTime = System.nanoTime();
        long durationSequential = endTime - startTime;

        // 测量并行计算的时间
        startTime = System.nanoTime();
        int sumParallel = sumParallel(numbers);
        endTime = System.nanoTime();
        long durationParallel = endTime - startTime;

        System.out.println("串行计算耗时 (毫秒)： " + durationSequential / 1000000);
        System.out.println("并行计算耗时 (毫秒)： " + durationParallel / 1000000);
    }
}

串行计算耗时 (毫秒)： 152
并行计算耗时 (毫秒)： 60