Using PdfStamper How I can save the merged PDF under a folder using itext then read it

I need to save my merged PDF on my hard disk then load it as final PDF

below is my code (with Safri on IPAD the PDF alwasy is empty)

            PdfReader reader = new PdfReader(folder + fileName);
            PdfStamper stamper = new PdfStamper( reader, out, '\0', true );
            AcroFields fields = stamper.getAcroFields();
            String fdfContent = (String) request.getAttribute("fdfContent");
            FdfReader fdfReader = new FdfReader(fdfContent.getBytes());
            fields.setFields(fdfReader);
            out.flush();
            sta开发者_高级运维mper.close();
            reader.close();

Many thanks

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use

PdfStamper stamper = new PdfStamper( reader, out, '\0', false );
stamper.setFormFlattening(true);