java执行windows命令，将结果保存起来

public class Test {
 public static void main(String[] args) throws IOException{
  Process p = Runtime.getRuntime().exec("cmd.exe /c net start");
   InputStream is = p.getInputStream();
   int len = is.read();
   byte[] buff = new byte[len];
   is.read(buff);
   FileOutputStream fos = new FileOutputStream("c://start.txt");
   fos.write(buff);
   System.out.println(new String(buff));
  
 }
}