Usando o serviço Assembler no AEM Forms using-assembler-service-in-aem-forms

protected void doPost(SlingHttpServletRequest request, SlingHttpServletResponse response) {
        log.debug("In Assemble Uploaded Files");

        Map<String, Object> mapOfDocuments = new HashMap<String, Object>();
        final boolean isMultipart = org.apache.commons.fileupload.servlet.ServletFileUpload.isMultipartContent(request);
        DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder docBuilder = null;
        try {
            docBuilder = docFactory.newDocumentBuilder();
        } catch (ParserConfigurationException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        org.w3c.dom.Document ddx = docBuilder.newDocument();
        Element rootElement = ddx.createElementNS("http://ns.adobe.com/DDX/1.0/", "DDX");

        ddx.appendChild(rootElement);
        Element pdfResult = ddx.createElement("PDF");
        pdfResult.setAttribute("result", "GeneratedDocument.pdf");
        rootElement.appendChild(pdfResult);
        if (isMultipart) {
            final java.util.Map<String, org.apache.sling.api.request.RequestParameter[]> params = request
                    .getRequestParameterMap();
            for (final java.util.Map.Entry<String, org.apache.sling.api.request.RequestParameter[]> pairs : params
                    .entrySet()) {
                final String k = pairs.getKey();

                final org.apache.sling.api.request.RequestParameter[] pArr = pairs.getValue();
                final org.apache.sling.api.request.RequestParameter param = pArr[0];

                try {
                    if (!param.isFormField()) {
                        final InputStream stream = param.getInputStream();
                        log.debug("the file name is " + param.getFileName());
                        log.debug("Got input Stream inside my servlet####" + stream.available());
                        com.adobe.aemfd.docmanager.Document document = new Document(stream);
                        mapOfDocuments.put(param.getFileName(), document);
                        org.w3c.dom.Element pdfSourceElement = ddx.createElement("PDF");
                        pdfSourceElement.setAttribute("source", param.getFileName());
                        pdfSourceElement.setAttribute("bookmarkTitle", param.getFileName());
                        pdfResult.appendChild(pdfSourceElement);
                        log.debug("The map size is " + mapOfDocuments.size());
                    } else {
                        log.debug("The form field is" + param.getString());

                    }
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }

            }
        }

        com.adobe.aemfd.docmanager.Document ddxDocument = documentServices.orgw3cDocumentToAEMFDDocument(ddx);
        Document assembledDocument = documentServices.assembleDocuments(mapOfDocuments, ddxDocument);
        String path = documentServices.saveDocumentInCrx("/content/ocrfiles", assembledDocument);
        JSONObject jsonObject = new JSONObject();
        try {
            jsonObject.put("path", path);
            response.setContentType("application/json");
            response.setHeader("Cache-Control", "nocache");
            response.setCharacterEncoding("utf-8");
            PrintWriter out = null;
            out = response.getWriter();
            out.println(jsonObject.toString());

        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

}