Java获取ip地址的几种方法

以下内容介绍下java获取ip地址的几种思路。

１、直接利用java.net.InetAddress类获取，不过这种方法只在windows环境下有效，在linux环境下只能获取localhost地址（即/etc/hosts文件内容）

　　代码如下：　

     import java.net.InetAddress;

     /**
      * This method works well in windows system.
      * In Linux system it returns 127.0.0.1 the content of the hosts file.
      */
     public static void getIpAddressInWindows() {
         try {
             InetAddress address = InetAddress.getLocalHost();
             System.out.println("Host Name: " + address.getHostName());
             System.out.println("Host Address: " + address.getHostAddress());

         } catch (UnknownHostException e) {
             e.printStackTrace();
         }
     } 

２、可以在linux下正常工作的方法，代码如下：

　　　 import java.net.Inet4Address;
　　　 import java.net.InetAddress;
　　　 import java.net.NetworkInterface;
　　　 import java.net.SocketException;
　　　 import java.net.UnknownHostException;
　　　 import java.util.Enumeration;

    /**
     * This method is used to get all ip addresses from the network interfaces.
     * network interfaces: eth0, wlan0, l0, vmnet1, vmnet8
     */
    public static void getAllIpAddress() {
        try {
            //get all network interface
            Enumeration<NetworkInterface> allNetworkInterfaces =
                    NetworkInterface.getNetworkInterfaces();
            NetworkInterface networkInterface = null;

            //check if there are more than one network interface
            while (allNetworkInterfaces.hasMoreElements()) {
                //get next network interface
                networkInterface = allNetworkInterfaces.nextElement();
                //output interface's name
                System.out.println("network interface: " +
                        networkInterface.getDisplayName());

                                //get all ip address that bound to this network interface
                Enumeration<InetAddress> allInetAddress =
                        networkInterface.getInetAddresses();

                InetAddress ipAddress = null;

                //check if there are more than one ip addresses
                //band to one network interface
                while (allInetAddress.hasMoreElements()) {
                    //get next ip address
                    ipAddress = allInetAddress.nextElement();
                    if (ipAddress != null && ipAddress instanceof Inet4Address) {
                        System.out.println("ip address: " +
                                ipAddress.getHostAddress());
                    }
                }
            }

        } catch (SocketException e) {
            e.printStackTrace();
        }
    }//end method getAllIpAddress
                            

上边这种方法有些不足之处，它会输出所有的网卡上的ip地址，有时候我们只需一个或几个单独的网卡ip即可，可以通过如下方法获得：　　　　

　　　　　　import java.net.Inet4Address;
　　　　　　import java.net.InetAddress;
　　　　　　import java.net.NetworkInterface;
　　　　　　import java.net.SocketException;
　　　　　　import java.net.UnknownHostException;
　　　　　　import java.util.Enumeration;

       /**
      * This method is used to get ip address by network interface's name.
      * @param networkInterfaceName network interface's name
      * @return return true if get ip address successfully,
      * otherwise return false.
      */
     public static boolean getIpAddrByName(String networkInterfaceName) {
         try {
 　　　　　　　 //get network interface by name
             NetworkInterface networkInterface =
                     NetworkInterface.getByName(networkInterfaceName);
             if (networkInterface == null) {
                 return false;
             }
             System.out.println("network interface: " +
                     networkInterface.getDisplayName());

             InetAddress ipAddress = null;
             //get all ip addresses band to this interface
             Enumeration<InetAddress> addresses = networkInterface.getInetAddresses();

             while (addresses.hasMoreElements()) {
                 ipAddress = addresses.nextElement();

                 if (ipAddress != null && ipAddress instanceof Inet4Address) {
                     System.out.println("ip address: " +
                             ipAddress.getHostAddress());
                 }
             }
         } catch (SocketException e) {
             e.printStackTrace();
         }

         return true;
     }// end method getIpAddrByName