CODEWITHSUNDEEP
javaexcelapache-poi
user1274028
user1274028

Reputation: 41

Write different data types to excel using POI

I am trying to export data from a database to Excel. I have the data exported and currently being stored in an ArrayList (this can be changed). I have been able to export the data to excel but all of the values are being exported as Strings, I need them to keep their data type i.e currency/numeric.

I am using Apache POI and am having difficult with setting the data type of the fields to anything other than String. Am I missing something? Can someone please advise me on a better way of doing this? Any assistance on this would be greatly appreciated.

public static void importDataToExcel(String sheetName, ArrayList header, ArrayList data, File xlsFilename, int sheetNumber)
        throws HPSFException, FileNotFoundException, IOException {

    POIFSFileSystem fs = new POIFSFileSystem();
    HSSFWorkbook wb = new HSSFWorkbook(new FileInputStream(xlsFilename));
    HSSFSheet sheet = wb.createSheet(sheetName);

    int rowIdx = 0;
    short cellIdx = 0;

    // Header
    HSSFRow hssfHeader = sheet.createRow(rowIdx);
    HSSFCellStyle cellStyle = wb.createCellStyle();
    cellStyle.setAlignment(HSSFCellStyle.ALIGN_CENTER);
    for (Iterator cells = header.iterator(); cells.hasNext();) {
        HSSFCell hssfCell = hssfHeader.createCell(cellIdx++);
        hssfCell.setCellStyle(cellStyle);
        hssfCell.setCellValue((String) cells.next());
    }
    // Data

    rowIdx = 1;
    for (Iterator rows = data.iterator(); rows.hasNext();) {
        ArrayList row = (ArrayList) rows.next();
        HSSFRow hssfRow = (HSSFRow) sheet.createRow(rowIdx++);
        cellIdx = 0;
        for (Iterator cells = row.iterator(); cells.hasNext();) {
            HSSFCell hssfCell = hssfRow.createCell(cellIdx++);
            hssfCell.setCellValue((String) cells.next());
        }
    }
    Logfile.log("sheetNumber = " + sheetNumber);
    wb.setSheetName(sheetNumber, sheetName);
    try {
        FileOutputStream out = new FileOutputStream(xlsFilename);
        wb.write(out);
        out.close();
    } catch (IOException e) {
        throw new HPSFException(e.getMessage());
    }

}

Upvotes: 0

Views: 4812

Answers (1)

Boris the Spider
Boris the Spider

Reputation: 61168

You need to check for the class of your cell value before you cast:

public static void importDataToExcel(String sheetName, List<String> headers, List<List<Object>> data, File xlsFilename, int sheetNumber)
        throws HPSFException, FileNotFoundException, IOException {

    POIFSFileSystem fs = new POIFSFileSystem();
    Workbook wb;
    try {
        wb = WorkbookFactory.create(new FileInputStream(xlsFilename));
    } catch (InvalidFormatException ex) {
        throw new IOException("Invalid workbook format");
    }
    Sheet sheet = wb.createSheet(sheetName);

    int rowIdx = 0;
    int cellIdx = 0;

    // Header
    Row hssfHeader = sheet.createRow(rowIdx);
    CellStyle cellStyle = wb.createCellStyle();
    cellStyle.setAlignment(HSSFCellStyle.ALIGN_CENTER);
    for (final String header : headers) {
        Cell hssfCell = hssfHeader.createCell(cellIdx++);
        hssfCell.setCellStyle(cellStyle);
        hssfCell.setCellValue(header);
    }
    // Data

    rowIdx = 1;
    for (final List<Object> row : data) {
        Row hssfRow = sheet.createRow(rowIdx++);
        cellIdx = 0;
        for (Object value : row) {
            Cell hssfCell = hssfRow.createCell(cellIdx++);
            if (value instanceof String) {
                hssfCell.setCellValue((String) value);
            } else if (value instanceof Number) {
                hssfCell.setCellValue(((Number) value).doubleValue());
            } else {
                throw new RuntimeException("Cell value of invalid type " + value);
            }
        }
    }
    wb.setSheetName(sheetNumber, sheetName);
    try {
        FileOutputStream out = new FileOutputStream(xlsFilename);
        wb.write(out);
        out.close();
    } catch (IOException e) {
        throw new HPSFException(e.getMessage());
    }
}

I have also added in generics - this makes the code a lot more readable. Also you need to avoid using the actual class where possible and use the interface, for example List not ArrayList and Row not HSSFRow.

Upvotes: 1

Related Questions