java获取本机ip地址

package com.zhangfeiyan;


import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.net.UnknownHostException;
import java.util.Enumeration;


public class IPAquire {
   private static volatile String cachedIpAddress;
  
   public static void main(String[] args) {
    String ip = getIp();
    System.out.println(ip);
}
   /**
    * 获取本机IP地址.
    * 有限获取外网IP地址. 也有可能是链接着路由器的最终IP地址.
    *
    * @return 本机IP地址
    */
   public static String getIp() {
       if (null != cachedIpAddress) { 
           return cachedIpAddress;
       }
       Enumeration<NetworkInterface> netInterfaces = null;
       try {
           netInterfaces = NetworkInterface.getNetworkInterfaces();
       } catch (final SocketException ex) {
           // throw new JobException(ex);
       }
       String localIpAddress = null;
       while (netInterfaces.hasMoreElements()) {
           NetworkInterface netInterface = netInterfaces.nextElement();
           Enumeration<InetAddress> ipAddresses = netInterface.getInetAddresses();
           while (ipAddresses.hasMoreElements()) {
               InetAddress ipAddress = ipAddresses.nextElement();
               if (isPublicIpAddress(ipAddress)) {
                   String publicIpAddress = ipAddress.getHostAddress();
                   cachedIpAddress = publicIpAddress;
                   return publicIpAddress;
               }
               if (isLocalIpAddress(ipAddress)) {
                   localIpAddress = ipAddress.getHostAddress();
               }
           }
       }
       cachedIpAddress = localIpAddress;
       return localIpAddress;
   }

   /**
    * 获取本机Host名称.
    *
    * @return 本机Host名称
    */
   public String getHostName() {
       return getLocalHost().getHostName();
   }

   private static boolean isPublicIpAddress(final InetAddress ipAddress) {
       return !ipAddress.isSiteLocalAddress() && !ipAddress.isLoopbackAddress() && !isV6IpAddress(ipAddress);
   }

   private static boolean isLocalIpAddress(final InetAddress ipAddress) {
       return ipAddress.isSiteLocalAddress() && !ipAddress.isLoopbackAddress() && !isV6IpAddress(ipAddress);
   }

   private static boolean isV6IpAddress(final InetAddress ipAddress) {
       return ipAddress.getHostAddress().contains(":");
   }

   private static InetAddress getLocalHost() {
       InetAddress result = null;
       try {
           result = InetAddress.getLocalHost();
       } catch (final UnknownHostException ex) {
           // throw new JobException(ex);
       }
       return result;
   }
}