Validate IP Addresses with Regular Expression in Java

Run Application

Create new java file named Main.java. This file use Regular Expression check validate IP address as below:

package regular_expression;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {

	private static boolean isValid(String ip) {
		String ipPattern = "^([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\.([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\.([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\.([01]?\\d\\d?|2[0-4]\\d|25[0-5])$";
		Pattern pattern = Pattern.compile(ipPattern, Pattern.CASE_INSENSITIVE);
		Matcher matcher = pattern.matcher(ip);
		return matcher.matches();
	}

	public static void main(String[] args) {

		String ip1 = "12.45.13";
		boolean result1 = isValid(ip1);
		System.out.println("Result 1: " + result1);

		String ip2 = "12.45.13.78";
		boolean result2 = isValid(ip2);
		System.out.println("Result 2: " + result2);

	}

}

Output

Result 1: false
Result 2: true