Damaged downloaded excel file using version 3.0.1 of POI

[Julien Martin]

Hello,
I have a problem with a dowloaded excel file produced by POI. It says the
file is damaged...

Here is the method I use in order to download the file:

    public String exportEntireTable() {
        FacesContext facesContext = FacesContext.getCurrentInstance();
        if (!facesContext.getResponseComplete()) {
            String fileName = "export.xls";//todo

            ServletContext servletContext = (ServletContext)
            facesContext.getExternalContext().getContext();
            String contentType = servletContext.getMimeType (fileName);

            HttpServletResponse response = (HttpServletResponse)
            facesContext.getExternalContext().getResponse();
            response.setContentType(contentType);
            response.setHeader("Content-Disposition",
"attachment;filename=\"" + fileName + "\"");


            try {
                InputStream in = new
ByteArrayInputStream(retrieveEntireTable());//returns an array of bytes for
the file
                //BlockingInputStream bis = new BlockingInputStream(in);
                ServletOutputStream out = response.getOutputStream();

                byte[] buf = new byte[512];
                int bytesRead;
                while ((bytesRead = in.read(buf)) != -1) {
                    out.write(buf, 0, bytesRead);
                }

                out.flush();
                facesContext.responseComplete();
            } catch (IOException e) {
                log.fatal("IOException", e);
                throw new RuntimeException(e);
            }
        }
        return null;
    }

Can anyone please help?

Thanks in advance,

Julien.