How to put csv file after modification in flowfile content

[#1]

Hi Everyone,

I have csv file where i give to an ExecuteScript that reads and modify some cells, the questions is how to set the csv back to the flowfile content .

here is my script. THANK YOU

flowFile = session.write(flowFile,

        { inputStream, outputStream ->

            myAttr = flowFile.getAttribute('Mutations')

            def slurped = new JsonSlurper().parseText(myAttr)

            def builder = new JsonBuilder(slurped)

            for (b in slurped){

                part = b.cellname.split("(?<=\\D)(?=\\d)")

                myrow =  ((int)part[0]) - 66

                mycol = part[1]

                myvalue = b.value 

                Workbook wb = WorkbookFactory.create(inputStream);

                Sheet sheet = wb.getSheetAt(0);

                Row row = sheet.getRow(0);

                Cell cell = row.getCell(0);

                cell.setCellValue(8888);

            }

            outputStream.write(builder.toPrettyString().getBytes(StandardCharsets.UTF_8))

        } as StreamCallback)

session.transfer(flowFile, ExecuteScript.REL_SUCCESS)