package com.basic;

import java.util.ArrayList;

import java.util.List;

import java.util.Random;

/**

* @program JavaBooks

* @description: parallel的小例子

* @author: mf

* @create: 2020/01/01 16:04

*/

public class T30 {

public static void main(String[] args) {

List<Integer> nums = new ArrayList<>();

Random r = new Random();

for (int i = 0; i < 10000; i++) nums.add(100000 + r.nextInt(100000));

long start = System.currentTimeMillis();

nums.forEach(v -> isPrime(v));

long end = System.currentTimeMillis();

System.out.println(end - start);

// 使用parallel stream api

start = System.currentTimeMillis();

nums.parallelStream().forEach(T30::isPrime);

end = System.currentTimeMillis();

System.out.println(end - start);

}

private static boolean isPrime(int num) {

for (int i = 2; i < num / 2; i++) {

if (num % i == 0) return false;

}

return true;

}

}