并行流和串行流

package com.mc.day1.lambda;

import org.junit.Test;

import java.time.Duration;
import java.time.Instant;
import java.util.stream.LongStream;

public class ForkJoin {

    @Test
    public void test(){
     //测试并行流  parallel（）  并行流和顺序流 sequential
        Instant now = Instant.now();
        long reduce = LongStream.rangeClosed(0, 1000000000L).parallel().reduce(0, Long::sum);
        Instant end = Instant.now();
        System.out.println(Duration.between(now,end).toMillis());
        //361ms


        //一般的没有用到并行流
        Instant now1 = Instant.now();
        long reduce1 = LongStream.rangeClosed(0, 1000000000L).sequential().reduce(0, Long::sum);
        Instant end1 = Instant.now();
        System.out.println(Duration.between(now1,end1).toMillis());
        //1889ms
        //可见并行流比顺序流效率高几乎六倍

    }
}