Apache POI evaluate formula

Question

I have some formulas in cells of my sheet, and I want to evaluate them after I insert some values. Ex :

My formula is =SUM(B1,B2)

Before values

Answer 1

You can use this.

 public static void triggerFormula(HSSFWorkbook workbook){      

                FormulaEvaluator evaluator = workbook.getCreationHelper().createFormulaEvaluator();
                HSSFSheet sheet = workbook.getSheetAt(0);
                int lastRowNo=sheet.getLastRowNum();        

                for(int rownum=0;rownum<=lastRowNo;rownum++){
                Row row;
                 if (sheet.getRow(rownum)!=null){
                         row= sheet.getRow(rownum);

                      int lastCellNo=row.getLastCellNum();

                          for(int cellnum=0;cellnum