com.alibaba.nacos.api.utils.NetUtils Maven / Gradle / Ivy
/*
* Copyright 1999-2020 Alibaba Group Holding Ltd.
*
* 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.
*/
package com.alibaba.nacos.api.utils;
import java.io.IOException;
import java.net.Inet4Address;
import java.net.Inet6Address;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.UnknownHostException;
import java.util.Enumeration;
/**
* Net utils.
*
* @author xuanyin.zy
*/
public class NetUtils {
private static String localIp;
/**
* Get local ip.
*
* @return local ip
*/
public static String localIP() {
if (!StringUtils.isEmpty(localIp)) {
return localIp;
}
String ip = System.getProperty("com.alibaba.nacos.client.naming.local.ip", findFirstNonLoopbackAddress());
return localIp = ip;
}
private static String findFirstNonLoopbackAddress() {
InetAddress result = null;
try {
int lowest = Integer.MAX_VALUE;
for (Enumeration nics = NetworkInterface.getNetworkInterfaces();
nics.hasMoreElements(); ) {
NetworkInterface ifc = nics.nextElement();
if (ifc.isUp()) {
if (ifc.getIndex() < lowest || result == null) {
lowest = ifc.getIndex();
} else {
continue;
}
for (Enumeration addrs = ifc.getInetAddresses(); addrs.hasMoreElements(); ) {
InetAddress address = addrs.nextElement();
boolean isLegalIpVersion =
Boolean.parseBoolean(System.getProperty("java.net.preferIPv6Addresses"))
? address instanceof Inet6Address : address instanceof Inet4Address;
if (isLegalIpVersion && !address.isLoopbackAddress()) {
result = address;
}
}
}
}
} catch (IOException ex) {
//ignore
}
if (result != null) {
return result.getHostAddress();
}
try {
return InetAddress.getLocalHost().getHostAddress();
} catch (UnknownHostException e) {
//ignore
}
return "resolve_failed";
}
}