利用 Base64 缩短 UUID 至22位
UUID还是比较常用的，尤其在web应用里。
有时在URL中传播，感觉比较长，于是想对其进行缩短，查询了一些资料，发现目前最短是到 22 位（使用URL传播非转义字符，结合Base64）
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废话少说，代码奉上：
public class UuidBase64ShortMap implements StringShortMap{ /** * *把UUID 转为 22位长字符串 */ ?public String shorter(String s) { char[] res = Base64.encode(asBytes(s)); return new String(res,0,res.length-2); } /** * *把22位长字符串转为 UUID */ public String recover(String s) { int len = s.length(); char[] chars = new char[len+2]; chars[len]=chars[len+1]='_'; for(int i=0;i<len;i++){ chars[i]=s.charAt(i); } return toUUID(Base64.decode(chars)).toString(); } public static byte[] asBytes(String id) { UUID uuid=UUID.fromString(id); long msb = uuid.getMostSignificantBits(); long lsb = uuid.getLeastSignificantBits(); byte[] buffer = new byte[16]; for (int i = 0; i < 8; i++) { buffer[i] = (byte) (msb >>> 8 * (7 - i)); } for (int i = 8; i < 16; i++) { buffer[i] = (byte) (lsb >>> 8 * (7 - i)); } return buffer; } public static UUID toUUID(byte[] byteArray) { long msb = 0; long lsb = 0; for (int i = 0; i < 8; i++) msb = (msb << 8) | (byteArray[i] & 0xff); for (int i = 8; i < 16; i++) lsb = (lsb << 8) | (byteArray[i] & 0xff); UUID result = new UUID(msb, lsb); return result; } public static void main(String[] args) { StringShortMap shortm = new UuidBase64ShortMap();// String uuid = "3b01174f-3139-4a5b-a949-bb7e80b55f91";// System.out.println(Base64.encode(uuid));// String shorter= shortm.shorter(uuid);// System.out.println(shorter);// System.out.println(shortm.recover(shorter) +"\t" + uuid); // for(int i=0;i<100000;i++){// String Uuid = UUID.randomUUID().toString();// System.out.println(Uuid +"\t" + shortm.shorter(Uuid));// } String[] uuids={"f6e0e040-be3d-4573-964c-88724a8fa7d3","c19b9de1-f33a-494b-afbe-f06817218d63","f08f0b2c-66fb-41a3-99c3-ac206089c3ad"}; for(String s :uuids){ System.out.println(shortm.shorter(s)); } }}运行结果
9uDgQL49RXOWTIhySo*n0wwZud4fM6SUuvvvBoFyGNYw8I8LLGb7QaOZw6wgYInDrQ?
有更好的方案，欢迎讨论！！
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