@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

    String generatedString = getAlphaNumericString(16);


    GcsFilename gcsFileName = new GcsFilename("feist*******2.appspot.com", generatedString);
    GcsFileMetadata metaData = gcsService.getMetadata(gcsFileName);

    while(metaData != null) {
        generatedString = getAlphaNumericString(16);
        gcsFileName = new GcsFilename("feist*********2.appspot.com", generatedString);
        metaData = gcsService.getMetadata(gcsFileName);
    }

    /*GcsFileOptions.Builder builder = new GcsFileOptions.Builder();

    builder.acl("public-read");*/

    GcsFileOptions instance = GcsFileOptions.getDefaultInstance();
    GcsOutputChannel outputChannel;
    outputChannel = gcsService.createOrReplace(gcsFileName, instance);
    copy(req.getInputStream(), Channels.newOutputStream(outputChannel));


    JSONObject jsonWriter = new JSONObject();
    jsonWriter.append("result", "ok");
    jsonWriter.append("path", generatedString);

    resp.setContentType("application/json; charset=UTF-8");
    PrintWriter out = resp.getWriter();
    out.print(jsonWriter.toString());

}