Question

I am writing a java servlet in a GWT app which handles the export functionality of a HighStock chart. I have used the ExportController and modified it for GWT. I have pointed the export url on client side javascript, to this new servlet. I can see that when I click download a png, the browser makes a post call to this new servlet, but i don’t get any parameters in the request. The request params(svg, options, etc) are all nulls.
Can someone point me to, what I am missing here?

Answer 1

Actually the highcharts export module sends a “multipart/form-data” request. I was trying to parse the parameters as get request. This is how you can parse a multipart/formdata request-

if (!ServletFileUpload.isMultipartContent(req)) {
            throw new ServletException("Not a file upload request");
        }

        ServletFileUpload upload = new ServletFileUpload();
        FileItemIterator iter;

        iter = upload.getItemIterator(req);
        while (iter.hasNext()) {
            FileItemStream item = iter.next();
            InputStream stream = item.openStream();
            if (item.isFormField()) {
                if (item.getFieldName().equalsIgnoreCase("svg")) {
                    svg = Streams.asString(stream);
                }

…
…
}
}

https://gist.github.com/4695345