如何使用Apache POI在已存在的Excel文件中创建新工作表

Question

I am trying to create a new excelsheet for the existing excel file, but i am getting error org.apache.poi.EmptyFileException . Below is my code

public static void main(String[] args)
    {
        XSSFWorkbook workbook = null;
        File file = new File("C:/Users/NewUser/Desktop/Sample.xls");
        FileOutputStream fileOut = null;
        try 
        {
            fileOut = new FileOutputStream(file);

             if (file.exists()) {
                    try {
                        workbook = (XSSFWorkbook)WorkbookFactory.create(file);
                    } catch (InvalidFormatException e) {
                        e.printStackTrace();
                    } catch (EncryptedDocumentException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                    XSSFSheet sheet = workbook.createSheet("Sample sheet2");
                }
                else{
                    workbook = new XSSFWorkbook();
                    XSSFSheet sheet = workbook.createSheet("Sample sheet1");
                }
        } 
        catch (FileNotFoundException e1) 
        {
            e1.printStackTrace();
        }


        try {
            workbook.write(fileOut);
            System.out.println("File Created Succesfully");
            fileOut.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

How to overcome with that exception and how to create multiple sheets with in a single excel file?

Answer 1

fileOut = new FileOutputStream(file);

erases your file, but it still exists ( file.exists() == true) ). So you are opening an empty file when using WorkbookFactory.create(...) and you get an EmptyFileException .

If you debug your prog and stop before the use of WorkbookFactory.create(...) you will see a zero file size for Sample.xls .