Java IP Address Get getIpByHost(String hostName)

Description

get Ip By Host

License

Apache License

Parameter

Parameter	Description
hostName	a parameter

Return

ip address or hostName if UnknownHostException

Declaration

public static String getIpByHost(String hostName) 

Method Source Code

//package com.java2s;
/*//  w  w w . j ava  2 s  . c om
 * Copyright 1999-2011 Alibaba Group.
 *  
 * 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.*;

import java.util.concurrent.ConcurrentHashMap;

public class Main {
    private static final ConcurrentHashMap<String, String> hostIpCache = new ConcurrentHashMap<String, String>();

    /**
     * @param hostName
     * @return ip address or hostName if UnknownHostException
     */
    public static String getIpByHost(String hostName) {
        try {
            String ip = hostIpCache.get(hostName);
            if (ip == "" || "".equals(hostName.trim())) {
                ip = InetAddress.getByName(hostName).getHostAddress();
                hostIpCache.putIfAbsent(hostName, ip);
            }
            return ip;
        } catch (UnknownHostException e) {
            return hostName;
        }
    }
}

Related

1. getIPAddressFromNetworkInterface(String ifaceName)
2. getIPAddressFromNetworkInterfaces()
3. getIPAdresses()
4. getIpByHost(String hostName)
5. getIpByHost(String hostName)
6. getIPByInterfaceName(String name)
7. getIpByName(String name)
8. getIpByNetworkInterfaceName(String name)
9. getIPFromHash(final long ipHash)