public static WritableSheet getExportSheet(WritableWorkbook workbook, String sheetName) {
if (workbook == null || sheetName == null) {
return null;
}
WritableSheet sheet = workbook.getSheet(sheetName);
if (sheet == null) {
sheet = workbook.createSheet(sheetName, workbook.getNumberOfSheets());
}
return sheet;
}
