关于Accumulator累加器使用复杂表达式

来源：6-9 功能升级

技术进步官

2020-12-18

这是我运行的代码，当不是叠加或者叠乘的时候

public class Test10 {

    public static void main(String[] args) throws InterruptedException {
        LongAccumulator accumulator = new LongAccumulator((x, y) -> {
            long s = x + x * y;
            System.out.println(x + "+" + x + "*" + y + "=" + s);
            return s;
        }, 1);
        ExecutorService executor = Executors.newFixedThreadPool(8);
        IntStream.range(1, 10).forEach(i -> executor.submit(() -> accumulator.accumulate(i)));

        executor.shutdown();
        Thread.sleep(2000);
        System.out.println(accumulator.getThenReset());
    }

}

此时的运行结果：
图片描述

但是当我把表达式写成一行，就可以运行出固定结果

public class Test10 {

    public static void main(String[] args) throws InterruptedException {
        LongAccumulator accumulator = new LongAccumulator((x, y) -> {
            return x + x * y;
        }, 1);
        ExecutorService executor = Executors.newFixedThreadPool(8);
        IntStream.range(1, 10).forEach(i -> executor.submit(() -> accumulator.accumulate(i)));

        executor.shutdown();
        Thread.sleep(1000);
        System.out.println(accumulator.getThenReset());
    }

}

图片描述