JAVA中的GUID可以包含空格嗎？

Question

我想知道JAVA中的GUID。 GUID可以包含一個空格或不包含？

我用下面的代碼

import java.util.UUID; 

UUID uuid = UUID.randomUUID(); 

String randomUUIDString = uuid.toString(); 

randomUUIDString可以包含空格？如果是，什麼是避免它的機會？

Answer 1

號從UUID.toString()

的UUID字符串表示的文檔是由這個BNF描述：

UUID     = <time_low> "-" <time_mid> "-" 
          <time_high_and_version> "-" 
          <variant_and_sequence> "-" 
          <node> 
    time_low    = 4*<hexOctet> 
    time_mid    = 2*<hexOctet> 
    time_high_and_version = 2*<hexOctet> 
    variant_and_sequence = 2*<hexOctet> 
    node     = 6*<hexOctet> 
    hexOctet    = <hexDigit><hexDigit> 
    hexDigit    = 
      "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" 
      | "a" | "b" | "c" | "d" | "e" | "f" 
      | "A" | "B" | "C" | "D" | "E" | "F" 

正如你可以看到，返回的字符串中的每個字符會來自AF，af，0-9或' - '的字符。