How to set integer value in the excel sheet created through java?

Question

When I create excel sheet through java ,the column which has number datatype in the oracle table, get converted to text format in excel.I want it to remain in the number format.Below is my code snippet for excel creation.

    public boolean prepareExcelFilefromQuery(String chanType,
                    Collection<List> queryDataRowWise, HttpServletResponse response)

            {
                List<String> queryDataColWise;
                HSSFRow row = null;
                HSSFCell cell = null;
                Integer rowCounter = 0;
                Integer colCounter;
                boolean success = false;
                try {

                    Iterator<List> rowIterator = queryDataRowWise.iterator();
                    HSSFWorkbook workbook = new HSSFWorkbook();
                    HSSFSheet sheet = workbook.createSheet(chanType + " Report");
                    System.out.println("First row/..." + sheet.getFirstRowNum());
                    while (rowIterator.hasNext()) {
                        colCounter = 0;

                        queryDataColWise = (List) rowIterator.next();
                        Iterator colIterator = queryDataColWise.iterator();

                        row = sheet.createRow(rowCounter++);
                        while (colIterator.hasNext()) {
                            cell = row.createCell(colCounter++);
                            Object o = colIterator.next();

                            if (o instanceof java.lang.String) {
                                String s = (String) o;
                                cell.setCellValue(s);
                            } else if (o instanceof java.lang.Double) {
                                Double d = (Double) o;
                                cell.setCellValue(d);
                            } else if (o instanceof java.lang.Integer) {
                                Integer i = (Integer) o;
                                 cell.setCellType(cell.CELL_TYPE_NUMERIC);
                                cell.setCellValue(i);
                            } else if (o instanceof java.util.Date) {
                                Date date = (Date) o;

                                SimpleDateFormat FORMATTER;

                                FORMATTER = new SimpleDateFormat("MM/dd/yyyy");
                                String date11 = FORMATTER.format(date);
                                HSSFCellStyle cellStyle = workbook.createCellStyle();
                                cellStyle.setDataFormat(HSSFDataFormat
                                        .getBuiltinFormat("m/d/yy"));
                                cell.setCellStyle(cellStyle);
                                cell.setCellValue(FORMATTER.parse(date11));
                            }
                        }
                    }

                    workbook.write(response.getOutputStream());
                    success = true;

                } catch (Exception e) {
                    logger.debug(
                            "Exception caught in prepareExcelFilefromQuery class ", e);
                    System.out
                            .println("Exception caught in prepareExcelFilefromQuery class ");
                    e.printStackTrace();

                } 
                }
                return success;
            }

Answer 1

It just use format like 0. More Format

CellStyle numberStyle = wb.createCellStyle();
numberStyle.setDataFormat(format.getFormat("0"));

CellStyle dateStyle = wb.createCellStyle();
dateStyle.setDataFormat(format.getFormat("d-mmm-yy"));