随机数帮助类

package util;import java.util.Random;import java.util.UUID;/** * @Title: RandomUtil.java * @Description: 随机数帮助类 */public class RandomUtil {    public static String randomUUID() {        return UUID.randomUUID().toString().replace("-", "");    }    public static String randomValue() {        UUID uuid = UUID.randomUUID();        long least = uuid.getLeastSignificantBits();        long most = uuid.getMostSignificantBits();        return ShortUrlUtils.encoding(Math.abs(least)) + ShortUrlUtils.encoding(Math.abs(most));    }    public static String randomValueByLength(int length){        return randomValue().substring(2, 2+length);    }    public  static int rand(int start,int end){        Random rand = new Random();        return rand.nextInt(end-start +1) +start ;    }}