Java URL Value Check isValidURL(String link)

Description

Checks a url is in a valid form or not.

License

Open Source License

Parameter

Parameter	Description
link	a parameter

Declaration

public static boolean isValidURL(String link) 

Method Source Code

//package com.java2s;
/*/*from  w  ww .j  a  v  a2s .  c  o m*/
 * Copyright (C) 2003-2011 eXo Platform SAS.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Affero General Public License
 * as published by the Free Software Foundation; either version 3
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see<http://www.gnu.org/licenses/>.
 */

import java.net.IDN;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {
    private static final String SPACE_STRING = " ";
    private static final String HTTP = "http";
    private static final String HTTP_PRTOCOL = "http://";
    private static final Pattern URL_PATTERN = Pattern
            .compile("^(([^:/?#]+):)?(//([^/?#]*))?([^?#]*)" + "(\\?([^#]*))?(#(.*))?");
    private static final int DOMAIN = 4;

    /**
     * Checks a url is in a valid form or not.
     * 
     * @param link
     * @return
     */
    public static boolean isValidURL(String link) {
        try {
            if ((link == null) || (link.length() == 0))
                return false;

            // Check the case that url has the domain name in the right form. Exg: .com, .org... or not.
            if (link.indexOf('.') == -1)
                return false;

            if (!URL_PATTERN.matcher(link).matches())
                return false;

            if (hasValidDomain(link))
                return true;

            URI uri = null;
            uri = new URI(IDN.toUnicode(link));

            String scheme = uri.getScheme();
            if (scheme == null) {
                link = HTTP_PRTOCOL + link;
                uri = new URI(IDN.toUnicode(link));
            }

            String host = uri.getHost();
            if ((host != null) && (host.contains(SPACE_STRING)))
                return false;

            uri.toURL();
        } catch (URISyntaxException e) {
            return false;
        } catch (MalformedURLException e) {
            return false;
        } catch (IllegalArgumentException e) {
            return false;
        }
        return true;
    }

    private static boolean hasValidDomain(String link) {

        if (!link.startsWith(HTTP))
            link = HTTP_PRTOCOL + link;

        Matcher m = URL_PATTERN.matcher(link);

        if (m.matches()) {
            String domain = m.group(DOMAIN);
            if ((domain != null) && (!domain.contains(SPACE_STRING)))
                return true;
        }
        return false;
    }
}

Related

1. isValidChannelUrl(String url)
2. isValidServerURL(String serverURL)
3. isValidSuccessfulSignInURL(String url)
4. isValidURL(CharSequence urlStr)
5. isValidURL(final String candidateString)
6. isValidURL(String url)
7. isValidURL(String url)
8. isValidURL(String url)
9. isValidUrl(String url)