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