Java URL to Host Name getHostAddressAsBytes(String url)

Description

Returns the Host Address of a given URL as byte[].

License

Apache License

Parameter

Parameter	Description
url	URL as a String

Exception

Parameter	Description
UnknownHostException	if Host Name cannot be mapped to IP Address

Return

Host IP Address, as byte[]

Declaration

public static byte[] getHostAddressAsBytes(String url) throws UnknownHostException 

Method Source Code

//package com.java2s;
/*/* ww w.j  a  va2s  .  c om*/
 * Copyright (C) 2008 Yohan Liyanage. 
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); 
 * you may not use this file except in compliance with the License. 
 * You may obtain a copy of the License at 
 * http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing, software 
 * distributed under the License is distributed on an "AS IS" BASIS, 
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
 * See the License for the specific language governing permissions and 
 * limitations under the License.
 */

import java.net.InetAddress;
import java.net.UnknownHostException;

public class Main {
    /**
     * Returns the Host Address of a given URL as byte[].
     * 
     * @param url URL as a String
     * 
     * @return Host IP Address, as byte[]
     * 
     * @throws UnknownHostException if Host Name cannot be mapped to IP Address
     * 
     * @see {@link #getHostAddress(String)}
     */
    public static byte[] getHostAddressAsBytes(String url) throws UnknownHostException {
        return InetAddress.getByName(getHostAddress(url)).getAddress();
    }

    /**
     * Returns the Host Address (IP Address) of the given 
     * URL. This method uses {@link InetAddress#getByName(String)}
     * to detect the IP Address of the given host.
     * 
     * @param url URL as a String
     * @return Host Address as String
     */
    public static String getHostAddress(String url) throws UnknownHostException {

        // Split from :// and : and get Host Name Part
        String hostAddress = url.split("://")[1].split(":")[0];

        // For localhost loopback, detect real network name
        if (hostAddress.equals("localhost") || hostAddress.equals("127.0.0.1")) {

            // Local Address : Find Real Network IP
            hostAddress = InetAddress.getLocalHost().getHostAddress();

        } else {
            // Find IP Address
            hostAddress = InetAddress.getByName(hostAddress).getHostAddress();
        }

        return hostAddress;
    }
}

Related

1. getHost(String url)
2. getHost(String url)
3. getHost(String urlString)
4. getHost(String urlString)
5. getHost(URL url)
6. getHostAndPort(final URL url)
7. getHostAndPortFromUrl(String url)
8. getHostFromURL(final String urlSpec)
9. getHostname(String completeUrl)