catch(SocketException se){

            System.err.println("错误："+se.getMessage());

        }       

    }

    private static String bytes2mac(byte[] bytes){

        //MAC地址应为6字节

if(bytes.length!=6){                                                    

            System.err.println("MAC地址数据有错！");

            return null;

        }

        StringBuffer macString=new StringBuffer();

        byte currentByte;

        for(int i=0;i<bytes.length;i++){

            //与11110000作按位与运算以便读取当前字节高4位

currentByte=(byte)((bytes[i]&240)>>4);                                              macString.append(Integer.toHexString(currentByte));

            //与00001111作按位与运算以便读取当前字节低4位

                currentByte=(byte)((bytes[i]&15));                                 

            macString.append(Integer.toHexString(currentByte));

            //追加字节分隔符“-”

macString.append("-");                                             

        }

        //删除多加的一个“-”

macString.delete(macString.length()-1,macString.length()); 

//统一转换成大写形式后返回