获得mac地址的方法

第三种方法是用UDP协议来发送查询mac指令然后返回值中解析mac。个人认为这是最好的方法（暂时）速度最快
<%
String smac = "";
String sip = request.getHeader("x-forwarded-for");  
if(sip == null || sip.length() == 0 || "unknown".equalsIgnoreCase(sip)) {  
    sip = request.getHeader("Proxy-Client-IP");  
}  
if(sip == null || sip.length() == 0 || "unknown".equalsIgnoreCase(sip)) {  
    sip = request.getHeader("WL-Proxy-Client-IP");  
}  
if(sip == null || sip.length() == 0 || "unknown".equalsIgnoreCase(sip)) {  
    sip = request.getRemoteAddr();  
}  
UdpGetClientMacAddr umac = new UdpGetClientMacAddr(sip);
smac = umac.GetRemoteMacAddr();
%>
...
<input value=<%=smac %> name="userMacAddr" size="20" style="width:150px" readonly="yes">

UdpGetClientMacAddr.java
package cch;
import java.io.*;
import java.net.*;
public class UdpGetClientMacAddr {
    private String sRemoteAddr;
    private int iRemotePort=137;
    private byte[] buffer = new byte[1024];
    private DatagramSocket ds=null;
    
    public UdpGetClientMacAddr(String strAddr) throws Exception{
        sRemoteAddr = strAddr;
        ds = new DatagramSocket();
    }
    
    protected final DatagramPacket send(final byte[] bytes) throws IOException {
     DatagramPacket dp = new DatagramPacket(bytes,bytes.length,InetAddress.getByName(sRemoteAddr),iRemotePort);
     ds.send(dp);
        return dp;
    }
    
    protected final DatagramPacket receive() throws Exception {
     DatagramPacket dp = new DatagramPacket(buffer,buffer.length);
     ds.receive(dp);
     return dp;
    }
    
    protected byte[] GetQueryCmd() throws Exception {
     byte[] t_ns = new byte[50];
     t_ns[0] = 0x00;
        t_ns[1] = 0x00;
        t_ns[2] = 0x00;
        t_ns[3] = 0x10;
        t_ns[4] = 0x00;
        t_ns[5] = 0x01;
        t_ns[6] = 0x00;
        t_ns[7] = 0x00;
        t_ns[8] = 0x00;
        t_ns[9] = 0x00;
        t_ns[10] = 0x00;
        t_ns[11] = 0x00;
        t_ns[12] = 0x20;
        t_ns[13] = 0x43;
        t_ns[14] = 0x4B;
        
        for(int i = 15; i < 45; i++)
        {
         t_ns = 0x41;
        }
        
        t_ns[45] = 0x00;
        t_ns[46] = 0x00;
        t_ns[47] = 0x21;
        t_ns[48] = 0x00;
        t_ns[49] = 0x01;
     return t_ns;
    }
    
    protected final String GetMacAddr(byte[] brevdata) throws Exception {
    
     int i = brevdata[56] * 18 + 56;
        String sAddr="";
        StringBuffer sb = new StringBuffer(17);
                
        for(int j = 1; j < 7;j++)
        {
         sAddr = Integer.toHexString(0xFF & brevdata);
            if(sAddr.length() < 2)
            {
             sb.append(0);
            }
            sb.append(sAddr.toUpperCase());
            if(j < 6) sb.append(':');
        }
        return sb.toString();
    }
    
    public final void close() {
     try
     {
      ds.close();
     }
     catch (Exception ex){
      ex.printStackTrace();
     }
    }
    
    public final String GetRemoteMacAddr() throws Exception {
     byte[] bqcmd = GetQueryCmd();
     send(bqcmd);
     DatagramPacket dp = receive();
        String smac = GetMacAddr(dp.getData());
        close();
        
        return smac;
    }
}