首先，你如果搜索“JAVA获取本机IP地址”，基本上搜到的资料全是无用的。
比如这篇：实际上的代码在复杂环境下是不准的 网上一个比较普遍的说法是InetAddress.getLocalHost().getHostAddress()似乎很简单，但忽略了一个问题，即IP地址在现在的网络环境更加复杂了，比如有Lan，WIFI，蓝牙热点，虚拟机网卡...即存在很多的网络接口（network interfaces），每个网络接口就包含一个IP地址，并不是所有的IP地址能被外部或局域网访问，比如说虚拟机网卡地址等等。也就是说InetAddress.getLocalHost().getHostAddress()的IP不一定是正确的IP。写代码前，先明确一些规则：
- 127.xxx.xxx.xxx 属于"loopback" 地址，即只能你自己的本机可见，就是本机地址，比较常见的有127.0.0.1；
- 192.168.xxx.xxx 属于private 私有地址(site local address)，属于本地组织内部访问，只能在本地局域网可见。同样10.xxx.xxx.xxx、从172.16.xxx.xxx 到 172.31.xxx.xxx都是私有地址，也是属于组织内部访问；
- 169.254.xxx.xxx 属于连接本地地址（link local IP），在单独网段可用
- 从224.xxx.xxx.xxx 到 239.xxx.xxx.xxx 属于组播地址
- 比较特殊的255.255.255.255 属于广播地址
- 除此之外的地址就是点对点的可用的公开IPv4地址
获取本机IP地址的正确姿势：
package ipTest;import java.net.Inet4Address;import java.net.InetAddress;import java.net.NetworkInterface;import java.net.SocketException;import java.net.UnknownHostException;import java.util.Enumeration;public class Test { public Test() { // TODO Auto-generated constructor stub } public static void main(String[] args) { // TODO Auto-generated method stub InetAddress ip; try { // 这种IP容易拿错 // System.out.println("Current IP address : " + // InetAddress.getLocalHost().getHostAddress()); // 不一定准确的IP拿法 // 出自比如这篇：http://www.cnblogs.com/zrui-xyu/p/5039551.html System.out.println("get LocalHost Address : " + getLocalHostAddress().getHostAddress()); // 正确的IP拿法 System.out.println("get LocalHost LAN Address : " + getLocalHostLANAddress().getHostAddress()); } catch (UnknownHostException e) { e.printStackTrace(); } } // 正确的IP拿法，即优先拿site-local地址 private static InetAddress getLocalHostLANAddress() throws UnknownHostException { try { InetAddress candidateAddress = null; // 遍历所有的网络接口 for (Enumeration ifaces = NetworkInterface.getNetworkInterfaces(); ifaces.hasMoreElements();) { NetworkInterface iface = (NetworkInterface) ifaces.nextElement(); // 在所有的接口下再遍历IP for (Enumeration inetAddrs = iface.getInetAddresses(); inetAddrs.hasMoreElements();) { InetAddress inetAddr = (InetAddress) inetAddrs.nextElement(); if (!inetAddr.isLoopbackAddress()) { // 排除loopback类型地址 if (inetAddr.isSiteLocalAddress()) { // 如果是site-local地址，就是它了 return inetAddr; } else if (candidateAddress == null) { // site-local类型的地址未被发现，先记录候选地址 candidateAddress = inetAddr; } } } } if (candidateAddress != null) { return candidateAddress; } // 如果没有发现 non-loopback地址.只能用最次选的方案 InetAddress jdkSuppliedAddress = InetAddress.getLocalHost(); if (jdkSuppliedAddress == null) { throw new UnknownHostException("The JDK InetAddress.getLocalHost() method unexpectedly returned null."); } return jdkSuppliedAddress; } catch (Exception e) { UnknownHostException unknownHostException = new UnknownHostException( "Failed to determine LAN address: " + e); unknownHostException.initCause(e); throw unknownHostException; } } //出自这篇：http://www.cnblogs.com/zrui-xyu/p/5039551.html //实际上的代码是不准的 private static InetAddress getLocalHostAddress() throws UnknownHostException { Enumeration allNetInterfaces; try { allNetInterfaces = NetworkInterface.getNetworkInterfaces(); InetAddress ip = null; while (allNetInterfaces.hasMoreElements()) { NetworkInterface netInterface = (NetworkInterface) allNetInterfaces.nextElement(); Enumeration addresses = netInterface.getInetAddresses(); while (addresses.hasMoreElements()) { ip = (InetAddress) addresses.nextElement(); if (!ip.isSiteLocalAddress() && !ip.isLoopbackAddress() && ip.getHostAddress().indexOf(":") == -1) { if (ip != null && ip instanceof Inet4Address) { return ip; } } } } } catch (SocketException e) { // TODO Auto-generated catch block e.printStackTrace(); } InetAddress jdkSuppliedAddress = InetAddress.getLocalHost(); if (jdkSuppliedAddress == null) { throw new UnknownHostException("The JDK InetAddress.getLocalHost() method unexpectedly returned null."); } return jdkSuppliedAddress; }}