网上搜了下 很多说这样的
Runtime.getRuntime().exec(balabala)
有用ipconfig的 有用nbtstat的
但是都报
java.io.IOException: CreateProcess error=2

感觉是win7的权限问题？

代码是这样的
<%
                String sip="";
                String smac="";
                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();
                }
        //本机过滤掉
        if(!"127.0.0.1".equals(sip))
        {
                Process process = Runtime.getRuntime().exec("nbtstat -a " + sip);
                InputStreamReader ir = new InputStreamReader(process.getInputStream());
                LineNumberReader input = new LineNumberReader(ir);
                String line;
                        while ((line = input.readLine()) != null)
                if (line.indexOf("MAC Address") > 0)
                {
                        smac = line.substring(line.indexOf("-") - 2);
                }
        }
        out.println(smac);
        out.println("<br>");
        out.println(sip);
%>
--
FROM 116.77.4.82