JAVA生成短8位UUID的实例讲解
作者:andy_miao858 时间:2021-08-21 04:26:19
短8位UUID思想其实借鉴微博短域名的生成方式,但是其重复概率过高,而且每次生成4个,需要随即选取一个。
本算法利用62个可打印字符,通过随机生成32位UUID,由于UUID都为十六进制,所以将UUID分成8组,每4个为一组,然后通过模62操作,结果作为索引取出字符,
这样重复率大大降低。
经测试,在生成一千万个数据也没有出现重复,完全满足大部分需求。代码贴出来供大家参考。
public static String[] chars = new String[] { "a", "b", "c", "d", "e", "f",
"g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s",
"t", "u", "v", "w", "x", "y", "z", "0", "1", "2", "3", "4", "5",
"6", "7", "8", "9", "A", "B", "C", "D", "E", "F", "G", "H", "I",
"J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V",
"W", "X", "Y", "Z" };
public static String generateShortUuid() {
StringBuffer shortBuffer = new StringBuffer();
String uuid = UUID.randomUUID().toString().replace("-", "");
for (int i = 0; i < 8; i++) {
String str = uuid.substring(i * 4, i * 4 + 4);
int x = Integer.parseInt(str, 16);
shortBuffer.append(chars[x % 0x3E]);
}
return shortBuffer.toString();
}
补充:生成 8 / 16 / 32 位的UUID
我就废话不多说了,大家还是直接看实例吧~
import java.util.UUID;
public class TestUUID {
// 得到16位的UUID-(数字)
public static String getUUID_16() {
int machineId = 1;// 最大支持1-9个集群机器部署
int hashCodeV = UUID.randomUUID().toString().hashCode();
if (hashCodeV < 0) {// 有可能是负数
hashCodeV = -hashCodeV;
}
String string = machineId + String.format("%015d", hashCodeV);
return string;
}
// 得到32位的UUID-(数字)
public static String getUUID_32() {
return UUID.randomUUID().toString().replace("-", "").toLowerCase();
}
//得到8位的UUID-(码)
public static String[] chars = new String[] { "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n",
"o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z", "0", "1", "2", "3", "4", "5", "6", "7", "8",
"9", "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T",
"U", "V", "W", "X", "Y", "Z" };
public static String getUUID_8() {
StringBuffer shortBuffer = new StringBuffer();
String uuid = UUID.randomUUID().toString().replace("-", "");
for (int i = 0; i < 8; i++) {
String str = uuid.substring(i * 4, i * 4 + 4);
int x = Integer.parseInt(str, 16);
shortBuffer.append(chars[x % 0x3E]);
}
return shortBuffer.toString();
}
public static void main(String[] args) {
System.out.println(getUUID_8());
}
}
以上为个人经验,希望能给大家一个参考,也希望大家多多支持脚本之家。如有错误或未考虑完全的地方,望不吝赐教。
来源:https://blog.csdn.net/andy_miao858/article/details/9530245
标签:JAVA,UUID
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