Thanks for your posting and using Aspose.Cells.
We have evaluated your issue and we are afraid, CellDataTable can only hold data and not style information. You cannot merge data and style information together. You will have to do it step by step.
First you will import your data from CellDataTable into your worksheet as you have already done, then after that you will selectively set the style of your desired cells.
Please see the following code, it sets the font color of cell A1 to red. You can select your cells in the same way and set their styles.
I have attached the sample Excel file and the output Excel file generated by the code for your reference
String filePath = “F:\Shak-Data-RW\Downloads\sample.xlsx”;
Workbook workbook = new Workbook(filePath);
Worksheet worksheet = workbook.getWorksheets().get(0);
//Access your desired cell
Cell cell = worksheet.getCells().get(“A1”);
//Set its font color to red
Style style = cell.getStyle();
workbook.save(filePath + “.out.xlsx”);