using Java temporary file for XLSX Apache poi

Question

.hi, i am trying to create a temporary .xlsx file and write to it using apache poi. i am getting EmptyFileException for creating workbook. this is the code:

public class Writer{
File file;
public File Write(List<FormData> l, Class elementClass)
{

    try {//create temp fiele here
        file = File.createTempFile(elementClass.getSimpleName(),".xlsx");
    } catch (IOException ex) {
        Logger.getLogger(Writer.class.getName()).log(Level.SEVERE, null, ex);
    }
    XSSFWorkbook workbook;
    XSSFSheet sheet;
    if (file.exists()) {
        FileInputStream inputStream;
        try {
            inputStream = new FileInputStream(file);
        } catch (FileNotFoundException ex) {
            throw new AspirinException(AspirinException.Type.INTERNAL_ERROR);
        }
        try {// this line gets error//
            workbook = (XSSFWorkbook) WorkbookFactory.create(inputStream);
        } catch (IOException | InvalidFormatException | EncryptedDocumentException ex) {
            throw new AspirinException(AspirinException.Type.INTERNAL_ERROR);
        }

        //...

it works fine if i use a real file. but for temp file it doesn't work. please help me with this. thanks

What do you think will your file be else than an empty file? WorkbookFactory.create(inputStream) tries creating a Workbookobject containing data read from the inputStream. This fails if there is no data to read. — Axel Richter
WorkbookFactory.create () is used for existing/filled Excel files. Create a XSSFWorkbook from scratch and then write () it to your tempfile — kiwiwings

centic centic · Accepted Answer · 2017-08-24T15:22:13

When you create a new file you will not need a file first, you can just start with a new Workbook:

Workbook wb = new XSSFWorkbook();

and then use the API to populate it. At the end you can write it to a new file via

try (OutputStream stream = new FileOutputStream(file)) {
    wb.write(stream);
}

using Java temporary file for XLSX Apache poi

2 Answers