Using java Pattern class to validate the FQDN, URL, E-Mail address hostname
import java.io.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Validator
{
private static final Pattern emailPattern = Pattern.compile("^[\\w\\-]([\\.\\w])+[\\w]+@([\\w\\-]+\\.)+[A-Z]{2,4}$", Pattern.CASE_INSENSITIVE);
private static final Pattern fqdnPattern = Pattern.compile("(?=^.{1,254}$)(^(?:(?!\\d+\\.|-)[a-zA-Z0-9_\\-]{1,63}(?<!-)\\.?)+(?:[a-zA-Z]{2,})$)", Pattern.CASE_INSENSITIVE);
private static final Pattern hostPattern = Pattern.compile("^(([a-zA-Z]|[a-zA-Z][a-zA-Z0-9\\-]*[a-zA-Z0-9])\\.)*([A-Za-z]|[A-Za-z][A-Za-z0-9\\-]*[A-Za-z0-9])$", Pattern.CASE_INSENSITIVE);
private static final Pattern urlPattern = Pattern.compile("[^(http\\:\\/\\/[a-zA-Z0-9_\\-]+(?:\\.[a-zA-Z0-9_\\-]+)*\\.[a-zA-Z]{2,4}(?:\\/[a-zA-Z0-9_]+)*(?:\\/[a-zA-Z0-9_]+\\.[a-zA-Z]{2,4}(?:\\?[a-zA-Z0-9_]+\\=[a-zA-Z0-9_]+)?)?(?:\\&[a-zA-Z0-9_]+\\=[a-zA-Z0-9_]+)*)$]", Pattern.CASE_INSENSITIVE);
public static boolean isInteger(String intVal)
{
try {
int i = new Integer(intVal);
return true;
} catch (Exception e) {
}
return false;
}
public static boolean isBoolean(String boolVal)
{
try {
boolean b = new Boolean(boolVal);
return true;
} catch (Exception e) {
}
return false;
}
public static boolean isFloat(String floatVal)
{
try {
float f = new Float(floatVal);
return true;
} catch (Exception e) {
}
return false;
}
public static boolean isLong(String logVal)
{
try {
long l = new Long(logVal);
return true;
} catch(Exception e) {
}
return false;
}
public static boolean isFQDN(String fqdnVal)
{
try {
Matcher matcher = fqdnPattern.matcher(fqdnVal);
return matcher.matches();
} catch (Exception e){
}
return false;
}
public static boolean isURL(String url)
{
try {
Matcher matcher = urlPattern.matcher(url);
return matcher.matches();
} catch (Exception e){
}
return false;
}
public static boolean isEmailAddr(String emailAddr)
{
try {
Matcher matcher = emailPattern.matcher(emailAddr);
return matcher.matches();
} catch (Exception e){
}
return false;
}
public static boolean isHost (String hostname)
{
try {
Matcher matcher = hostPattern.matcher(hostname);
return matcher.matches();
} catch (Exception e){
}
return false;
}
public static void main(String args[])
{
try {
String action = args[0];
String input = args[1];
boolean result = false;
if (action.equals("email")) {
result = isEmailAddr(input);
} else if (action.equals("host")) {
result = isHost(input);
} else if(action.equals("url")) {
result = isURL(input);
} else if(action.equals("fqdn")) {
result = isFQDN(input);
}
System.out.println("RESULT : " + result);
} catch (Exception e) {
e.printStackTrace();
}
}
}
