public static byte[] stringArray2byteArray(String[] strs) {
   if (strs == null) {
    return null;
   }  ByteArrayOutputStream byteOutput = new ByteArrayOutputStream();
   DataOutputStream out = new DataOutputStream(byteOutput);
   try {
    for (int i = 0; i < strs.length; i++) {
     byte[] data;
     try {
      data = strs[i].getBytes("utf-8");
     } catch (java.io.UnsupportedEncodingException e) {
      data = strs[i].getBytes();
     }
     out.writeInt(data.length);
     out.write(data);
    }
    out.flush();
    byte[] ret = byteOutput.toByteArray();
    out.close();
    byteOutput.close();
    return ret;
   } catch (IOException e) {
    return null;
   }
  }