public static boolean CheckMobilePhoneNum(String phoneNum) {
       String regex = "^(1[3-9]\\d{9}$)";
       if (phoneNum.length() == 11) {
             Pattern p = Pattern.compile(regex);
             Matcher m = p.matcher(phoneNum);
             if (m.matches()) {
                 return true;
             }
       }
       return false;
   }