import java.net.NetworkInterface;  import java.net.SocketException;  import java.util.Enumeration;    /**   *    * @author MrWang   * 获取客户端MAC地址   *    *   */    public class MacAddress {        public static String hexByte(byte b) {          String s = "000000" + Integer.toHexString(b);          return s.substring(s.length() - 2);      }        public static String getMAC() {          Enumeration<NetworkInterface> el;          String mac_s = "";          try {              el = NetworkInterface.getNetworkInterfaces();              while (el.hasMoreElements()) {                  byte[] mac = el.nextElement().getHardwareAddress();                  if (mac == null)                      continue;                  mac_s = hexByte(mac[0]) + "-" + hexByte(mac[1]) + "-"                          + hexByte(mac[2]) + "-" + hexByte(mac[3]) + "-"                          + hexByte(mac[4]) + "-" + hexByte(mac[5]);                  System.out.println(mac_s + "MAC地址");                }          } catch (SocketException e1) {              e1.printStackTrace();          }          return mac_s;      }        public static void main(String[] args) {          MacAddress m = new MacAddress();          m.getMAC();        }  }