public static void main(String[] args) throws IOException {
        String os = System.getProperties().getProperty("os.name");    //得到操作系统 xp 为"Windows XP"  其他的的楼主自己去试试
        Process pro = Runtime.getRuntime().exec("ipconfig");
        BufferedReader br = new BufferedReader(new InputStreamReader(pro.getInputStream()));
        List<String> rowList = new ArrayList();
        String temp;
        while((temp = br.readLine()) != null){
            rowList.add(temp );
        }
        for (String string : rowList) {
            String sm=  os.equals("Windows XP") ? "Subnet Mask" : "子网掩码" ; //这里只判断了win7个xp 
            if(string.indexOf("Subnet Mask") != -1){
                Matcher mc = Pattern.compile("\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}").matcher(string);
                if(mc.find()){
                    System.out.println("子掩码：" + mc.group());
                }else{
                    System.out.println("子掩码为空");
                }
            };
            String dg =  os.equals("Windows XP") ? "Default Gateway" : "默认网关" ; //这里只判断了win7个xp 
            if(string.indexOf("Default Gateway") != -1){
                Matcher mc = Pattern.compile("\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}").matcher(string);
                if(mc.find()){
                    System.out.println("默认网关：" + mc.group());
                }else{
                    System.out.println("默认网关为空");
                }
                return;
            };
        }
    }

------解决方案--------------------

探讨

用8楼的结果 我子网掩码是 255.255.255.0 得到的却是255.255.255.255


------解决方案--------------------
使用java.lang.Process类啊
将"ipconfig /all"传进去
Java code
/**
     * 获取linuxShell命令结果.
     * @param cmd 指令
     * @return 指令结果
     */
    public String getRuntimeExec(final String cmd) {
        BufferedReader bufferedReader = null;
        Process process = null;
        StringBuffer sb = new StringBuffer();
        try {
            String buffer;
            //System.out.println(cmd);
            process = Runtime.getRuntime().exec(cmd);
            // 得到结果
            bufferedReader = new BufferedReader(new InputStreamReader(process.getInputStream()));
            while ((buffer = bufferedReader.readLine()) != null) {
                sb.append(buffer + "\n");
            }
            if (sb.length() > 0) {
                sb.deleteCharAt(sb.length() - 1);
            }
            return sb.toString();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            System.out.println("execute failed.");
            return null;
        } finally {
            // 清理
            try {
                if (bufferedReader != null) {
                    bufferedReader.close();
                    bufferedReader = null;
                }

                if (process != null) {
                    process.destroy();
                    process = null;
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

------解决方案--------------------
也来弄一段：,只能得到掩码
Java code

public static void main(String args[]) {
        try {
            for (Enumeration<NetworkInterface> nis = NetworkInterface.getNetworkInte