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

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 + "]");
    }

}

mathRandom:[14]
uuidRandom:[428]