Java Host Resolve resolveHostName(String hostname)

Description

Resolves a given hostname by a canonical hostname.

License

Apache License

Parameter

Parameter	Description
hostname	the input hostname, which could be an alias

Exception

Parameter	Description
UnknownHostException	if the given hostname cannot be resolved

Return

the canonical form of the hostname, or null if it is null or empty

Declaration

public static String resolveHostName(String hostname)
        throws UnknownHostException 

Method Source Code

//package com.java2s;
/*//  w w w .  ja  v a 2  s .c  om
 * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
 * (the ?License??). You may not use this work except in compliance with the License, which is
 * available at www.apache.org/licenses/LICENSE-2.0
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied, as more fully set forth in the License.
 *
 * See the NOTICE file distributed with this work for information regarding copyright ownership.
 */

import java.net.InetAddress;

import java.net.UnknownHostException;

public class Main {
    /**
     * Resolves a given hostname by a canonical hostname. When a hostname alias (e.g., those specified
     * in /etc/hosts) is given, the alias may not be resolvable on other hosts in a cluster unless the
     * same alias is defined there. In this situation, loadufs would break.
     *
     * @param hostname the input hostname, which could be an alias
     * @return the canonical form of the hostname, or null if it is null or empty
     * @throws UnknownHostException if the given hostname cannot be resolved
     */
    public static String resolveHostName(String hostname)
            throws UnknownHostException {
        if (hostname == null || hostname.isEmpty()) {
            return null;
        }

        return InetAddress.getByName(hostname).getCanonicalHostName();
    }
}

Related

1. resolveHost(String hostname)
2. resolveHostname()
3. resolveHostname()
4. resolveHostName()
5. resolveHostName(final String hostName)