Question

What is the general approach to retrieve binary data that is posted to a Java Servlet? A byte[] is being posted to this servlet and I think I have to somehow parse the HttpServletRequest.getInputStream() and pull out the byte[] contents. Any ideas on how to change the below code to accomplish this?

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        StringBuilder stringBuilder = new StringBuilder();
        BufferedReader bufferedReader = null;
        try {
          InputStream inputStream = request.getInputStream();
          if (inputStream != null) {
           bufferedReader = new BufferedReader(new InputStreamReader(
        inputStream));
           char[] charBuffer = new char[128];
           int bytesRead = -1;
           while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
            stringBuilder.append(charBuffer, 0, bytesRead);
           }
          } else {
           stringBuilder.append("");
          }
        } catch (IOException ex) {
          throw ex;
        } finally {
          if (bufferedReader != null) {
           try {
            bufferedReader.close();
           } catch (IOException ex) {
            throw ex;
           }
          }
        }
        String body = stringBuilder.toString();
        System.out.println(body);
}

Answer 1

Don’t wrap your inputstream in any “Reader”s, as they convert from bytes to characters, and you want the bytes.