ip adress format control java

1import java.util.regex.Matcher;
2import java.util.regex.Pattern;
3
4// Java program to validate an IPv4 address
5class Main
6{
7	// an IPv4 address
8	private static final String INET4ADDRESS = "172.8.9.28";
9
10	private static final String IPV4_REGEX =
11					"^(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\." +
12					"(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\." +
13					"(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\." +
14					"(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$";
15
16	private static final Pattern IPv4_PATTERN = Pattern.compile(IPV4_REGEX);
17
18
19	public static boolean isValidInet4Address(String ip)
20	{
21		if (ip == null) {
22			return false;
23		}
24
25		Matcher matcher = IPv4_PATTERN.matcher(ip);
26
27		return matcher.matches();
28	}
29
30	public static void main(String[] args)
31	{
32		// Validate an IPv4 address
33		if (isValidInet4Address(INET4ADDRESS)) {
34			System.out.print("The IP address " + INET4ADDRESS + " is valid");
35		}
36		else {
37			System.out.print("The IP address " + INET4ADDRESS + " isn't valid");
38		}
39	}
40}