A POI related code block running dead slow

Question

I have below piece of code block containing loops:

Row row = null;
Cell cell = null;
String dataVal = null;
String[] temp = null;

for (int j = 0; j < thi         


        

Answer 1

try this...

for (int j = 0; j < this.myDataValues.size(); j++) {
  row = sheet.createRow(rownum++);
  temp = this.finalRowValues.get(j);

   for (int i = 0; i < 4; i++) {
       cell = row.createCell(i);

       dataVal = temp[i];

            if (NumberUtils.isNumber(dataVal)) {
                double d = Double.valueOf(dataVal);
                cell.setCellValue(d);
                cell.setCellType(Cell.CELL_TYPE_NUMERIC);
                cell.setCellStyle(styles.get("currency"));
            } else if (isValidDate(dataVal)) {
                cell.setCellValue(dataVal);
                cell.setCellType(Cell.CELL_TYPE_NUMERIC);
                cell.setCellStyle(styles.get("date"));
            } else {
                cell.setCellValue(temp[i]);
                cell.setCellType(Cell.CELL_TYPE_STRING);
                cell.setCellStyle(styles.get("data"));
            }
        }
    }
    for (int i = 0; i < 4; i++) {
      sheet.autoSizeColumn(i);
    }