Math.random()和UUID.randomUUID().toString()性能对比纯原

Posted 2020-09-21 万物生长

Math.random()和UUID.randomUUID().toString()性能对比

不言而喻,因为Math.random()不需要保证唯一性,所做的操作远比UUID消耗更小的性能,

在部分要求不严格的场景,通过Math.random()和其它业务唯一码仍能方便定位某条数据,此时就可以考虑使用Math.random().

压测代码如下:

package test;

import java.util.UUID;

public class Test {
    public static void main(String[] args) {
        mathRandom();
        uuidRandom();
    }

    public static void mathRandom() {
        long cost = 0;
        for (int i = 0; i < 100000; i++) {
            long start = System.currentTimeMillis();
            double d = Math.random();
            long end = System.currentTimeMillis();
            cost += (end - start);
        }
        System.out.println("mathRandom:[" + cost + "]");
    }

    public static void uuidRandom() {
        long cost = 0;
        for (int i = 0; i < 100000; i++) {
            long start = System.currentTimeMillis();
            String uudi = UUID.randomUUID().toString();
            long end = System.currentTimeMillis();
            cost += (end - start);
        }
        System.out.println("uuidRandom:[" + cost + "]");
    }

}

 

10万次循环,打印结果如下,相差近40倍:

mathRandom:[14]
uuidRandom:[428]