Nifi Unable to convert CSV to Excel using POI API

[#1]

I want to convert csv flowfile content into XLS file usin groovy script + POI API

I m using ivy to grab POI dependencies and it seems work well.

please find more details below:

This is my Nifi flow:

This is my script

@Grapes(@Grab(group='org.apache.poi', module='poi-ooxml', version='3.9'))
import org.apache.poi.ss.usermodel.*
import org.apache.poi.hssf.usermodel.*
import org.apache.poi.xssf.usermodel.*
import org.apache.poi.ss.util.*
import org.apache.poi.ss.usermodel.*
import org.apache.poi.hssf.extractor.*
import java.nio.charset.*
import java.io.*
import org.apache.commons.io.IOUtils

def flowFile = session.get()
def date = new Date()

if(!flowFile) return

flowFile = session.write(flowFile, {inputStream, outputStream ->
try {
    
Workbook wb = WorkbookFactory.create(inputStream,);
Sheet mySheet = wb.getSheetAt(0);


def record = IOUtils.toString(inputStream, StandardCharsets.UTF_8)
outputStream.write(record.getBytes(StandardCharsets.UTF_8))

wb.close();

} catch(e) {
 log.error("Error during processing", e)
 session.transfer(flowFile, REL_FAILURE)
}
} as StreamCallback)


def filename = flowFile.getAttribute('filename')+'.xlsx'
flowFile = session.putAttribute(flowFile, 'filename', filename) 

session.transfer(flowFile, REL_SUCCESS)

I get this error 

Any idea about this error ?

[#2 · Accepted solution]

I found a solution, this is my worked scripr:

@Grapes(@Grab(group='org.apache.poi', module='poi-ooxml', version='3.9'))
import com.opencsv.CSVReader
@Grapes(@Grab(group='com.opencsv', module='opencsv', version='4.2'))
import org.apache.poi.ss.usermodel.*
import org.apache.poi.xssf.streaming.*
import org.apache.poi.hssf.usermodel.*
import org.apache.poi.xssf.usermodel.*
import org.apache.poi.ss.util.*
import org.apache.poi.ss.usermodel.*
import org.apache.poi.hssf.extractor.*
import java.nio.charset.*
import java.io.*
import org.apache.commons.io.IOUtils

def flowFile = session.get()
def date = new Date()

if(!flowFile) return


flowFile = session.write(flowFile, {inputStream, outputStream ->
        SXSSFSheet sheet1 = null;
        CSVReader reader = null;
        Workbook wb = null;
        String generatedXlsFilePath = "/home/";
        FileOutputStream fileOutputStream = null;
  
  def filename = flowFile.getAttribute('filename')
  def path = flowFile.getAttribute('path')
  
            def nextLine = ''
            reader = new CSVReader(new FileReader(path+filename), ',');
 
 //Workbook wb = WorkbookFactory.create(inputStream,);
 //Sheet sheet1 = wb.createSheet("Feuille");
 
            wb = new SXSSFWorkbook(inputStream);
            sheet1 = (SXSSFSheet) wb.createSheet('Sheet');
 
            def rowNum = 0;
            while((nextLine = reader.readNext()) != null) {
                Row currentRow = sheet1.createRow(rowNum++);
                for(int i=0; i < nextLine.length; i++) {
                    if(NumberUtils.isDigits(nextLine[i])) {
                        currentRow.createCell(i).setCellValue(Integer.parseInt(nextLine[i]));
                    } else if (NumberUtils.isNumber(nextLine[i])) {
                        currentRow.createCell(i).setCellValue(Double.parseDouble(nextLine[i]));
                    } else {
                        currentRow.createCell(i).setCellValue(nextLine[i]);
                    }
                }
            }
  
 
            //fileOutputStream = new FileOutputStream(generatedXlsFilePath.trim());
            //wb.write(fileOutputStream);
            generatedXlsFilePath = generatedXlsFilePath + 'SAISIE_MAGASING.XLS'
            outputStream = new FileOutputStream(generatedXlsFilePath.trim());
 
            wb.write(outputStream);
            
                wb.close();
                //fileOutputStream.close();
                outputStream.close();
                reader.close();
                //outputStream.close();
                inputStream.close();
                
  
} as StreamCallback)



flowFile = session.putAttribute(flowFile, 'filename', filename)