Lendo um arquivo byte a byte

FacesContext context = FacesContext.getCurrentInstance();
		HttpServletResponse response = (HttpServletResponse) context.getExternalContext().getResponse();
		
		response.reset();
		response.setContentType("application/msword");
        response.setHeader("Content-Disposition", "attachment; filename=\"" + nomeArquivo + "\"");
        response.setHeader("Pragma", "");
        response.setHeader("Cache-Control", "max-age=1");
        response.setDateHeader("Expires", 1);
        
        OutputStream os = response.getOutputStream();
        
        os.write(bytes, 0, bytes.length);
        os.flush();
		os.close();
		context.responseComplete();