code: public static String UU(String uu16) {
          StringBuilder sb = new StringBuilder();
          sb.append(uu16.substring(0, 8));
          sb.append('-');
          sb.append(uu16.substring(8, 12));
          sb.append('-');
          sb.append(uu16.substring(12, 16));
          sb.append('-');
          sb.append(uu16.substring(16, 20));
          sb.append('-');
          sb.append(uu16.substring(20));
          return sb.toString();
      }
docs: 将紧凑格式的 UU16 字符串变成标准 UUID 格式的字符串
  
  @param uu16
  @return 标准 UUID 字符串