org.apache.activemq.util.InetAddressUtil Maven / Gradle / Ivy
/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.
*/
package org.apache.activemq.util;
import java.net.InetAddress;
import java.net.UnknownHostException;
public class InetAddressUtil {
/**
* When using the {@link java.net.InetAddress#getHostName()} method in an
* environment where neither a proper DNS lookup nor an /etc/hosts
* entry exists for a given host, the following exception will be thrown:
*
* java.net.UnknownHostException: <hostname>: <hostname>
* at java.net.InetAddress.getLocalHost(InetAddress.java:1425)
* ...
*
* Instead of just throwing an UnknownHostException and giving up, this
* method grabs a suitable hostname from the exception and prevents the
* exception from being thrown. If a suitable hostname cannot be acquired
* from the exception, only then is the UnknownHostException thrown.
*
* @return The hostname
* @throws UnknownHostException
* @see {@link java.net.InetAddress#getLocalHost()}
* @see {@link java.net.InetAddress#getHostName()}
*/
public static String getLocalHostName() throws UnknownHostException {
try {
return (InetAddress.getLocalHost()).getHostName();
} catch (UnknownHostException uhe) {
String host = uhe.getMessage(); // host = "hostname: hostname"
if (host != null) {
int colon = host.indexOf(':');
if (colon > 0) {
return host.substring(0, colon);
}
}
throw uhe;
}
}
}