UUID  通用唯一识别码 Universally Unique Identifier
唯一标识

java.util.UUID

UUID uuid = UUID.randomUUID();
System.out.println(uuid.toString());
f1619137-811c-4f30-96b4-b8544f1845a0
32个字符 + 4个-
32位 的 16进制字符   0~9 abcdef

标准的UUID格式
xxxxxxxx-xxxx-xxxx-xxxxxx-xxxxxxxxxx 
8-4-4-4-12
x 十六进制  0-9 或 a-f  


uuid 命令
man uuid 
# generate DCE 1.1 v1 UUID (time and node based)
uuid -v1
01c47915-4777-11d8-bc70-0090272ff725
        
# generate DCE 1.1 v3 UUID (name based)
uuid -v3 ns:URL http://codefun007.xyz/
c638027d-1d84-3ea0-ac14-90b1dc381bfc


# generate DCE 1.1 v4 UUID 4 (random data based)
uuid -v4
eb424026-6f54-4ef8-a4d0-bb658a1fc6cf
        


 java hex util  
 go google uuid 例子   
 c语言获取UUID