Regular expression for a hexadecimal number greater than 10 and should be even in length in java.

Following is the regular expression to match hexadecimal number greater than 10 with even length −

^(?=.{10,255}$)(?:0x)?\p{XDigit}{2}(?:\p{XDigit}{2})*$

Where,

• ^ − Matches the starting of the sentence.

• (?=.{10,255}$) − String ending with characters with 10 to 255.

• \p{XDigit}{2} − Two hexa-decimal characters.

• (?:\p{XDigit}{2})* − 0 or more sequences of double hexa-decimal characters.

• $ − Matches the end of the sentence.

Example 1

 Live Demo

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class JavaExample51 {
   public static void main(String[] args) {
      Scanner sc = new Scanner(System.in);
      String nums[] = new String[5];
      for(int i=0; i<nums.length; i++){
         System.out.println("Enter a hexa-decimal number: ");
         nums[i] = sc.nextLine();
      }
      //Regular expression to accept English alphabet
      String regex = "^(?=.{10,255}$)(?:0x)?\p{XDigit}{2}(?:\p{XDigit}{2})*$";
      //Creating a pattern object
      Pattern pattern = Pattern.compile(regex);
      for (String hex : nums) {
         //Creating a Matcher object
         Matcher matcher = pattern.matcher(hex);
         if(matcher.find()) {
            System.out.println(hex+" is valid");
         }else {
            System.out.println(hex+" is not valid");
         }
      }
   }
}

Output

Enter a hexa-decimal number:
0x1234567890
Enter a hexa-decimal number:
123456789
Enter a hexa-decimal number:
123456789012
Enter a hexa-decimal number:
sfdgdf35364
Enter a hexa-decimal number:
$@%#BV#*
0x1234567890 is valid
123456789 is not valid
123456789012 is valid
sfdgdf35364 is not valid
$@%#BV#* is not valid

Example 2

 Live Demo

import java.util.Scanner;
public class JavaExample {
   public static void main(String[] args) {
      Scanner sc = new Scanner(System.in);
      System.out.println("Enter a hexa-decimal number: ");
      String name = sc.nextLine();
      String regex = "^(?=.{10,255}$)(?:0x)?\p{XDigit}{2}(?:\p{XDigit}{2})*$";
      boolean result = name.matches(regex);
      if(result) {
         System.out.println("Given number is valid");
      }else {
         System.out.println("Given number is not valid");
      }
   }
}

Output 1

Enter your name:
0x1234567890
Given name is valid

Output 2

Enter a hexa-decimal number:
024587545
Given number is not valid