How to get column names and values from a Excel File in Katalon

I have read several posts on how to read Excel files but to be honest I got stuck and I think I need something simpler.

What I need to do is 2 things. Using the following sample table:

1. Get column names in a list of Strings. For example:

columnList = Name, FirstName, Email, Date

2. Get values from a specific column: For example:

parameter = FirstName (or Index, columns position are fixed)

valuesList = Smith, Gomez, Brown

I hope someone can help me. Thanks!

This is what I have tried: (I took it from other forums and modified it. This code is to get cell values from a column.

@Keyword def getCellValuesList(String xlFilePath, String sheetName, String colName) {
  def fis = new FilelnputStream(xlFilePath);
  def workbook = new XSSFWbrkbook(fis);
  def sheet def row def cell def totalRowCount String rsltValuesListTemp = 'value'
  List < String > rsltValuesList = new ArrayList < > () fis.close();
  WebUI.comment("rsltValuesListTemp = $rsltValuesListTemp")
  try {
    int col_Num = -1;
    sheet = workbook.getSheet(sheetName);
    row = sheet.getRow(0);
    for (int i = 0; i < row.getLastCellNum(); i++) {
      if (row.getCell(i).getStringCellValue().trim().equals(colName.trim()))
        col_Num = i;
    }
    row = sheet.getRow(1);
    WebUI.comment("Current row $row")
    while (rsltValuesListTemp != '') {
      cell = row.getCell(col_Num);
      WebUI.comment("Cell value $cell")
      if (cell.getCellTypeEnum() == CellType.STRING) {
        rsltValuesListTemp = cell.getStringCellValue();
        rsaValuesList.add(rsaValuesListTemp)
        WebUI.comment("rsaValuesList = $rsltValuesList")
      } else if (cell.getCellTypeEnum() == CellType.NUMER || cell.getCellTypeEnum() == CellType.FORMULA) {
        rsltValuesListTemp = String.valueOf(cell.getNumericCellValue());
        if (HSSFDateUtil.isCettDateFormatted(cell)) {
          DateFormat df = new SimpleDateFormat("dd/MM/yy");
          Date date = cell.getDateCellValue();
          rsltValuesListTemp = df.getStringCellValue(format(date));
        }
        rsltValuesList.add(rsltValuesListTemp)
        WebUI.comment("rsltValuesList = $rsltValuesList")
      } else if (cell.getCellTypeEnum() == CellType.BLANK)
        rsltValuesListTemp = "";
      else
        rsltValuesListTemp = String.vaueOf(cell.getSooleanCellValue());

      WebUI.comment("row = $row")
      WebUI.comment("rsaValuesList = $rsltValuesList")
    }
  } catch (Exception e) {
    e.printStackTrace();
    return "column " + colName + " does not exist in Excel";
  }
  WebUI.comment("List values for column $colName = $rsltValuesListTemp")
}
  

I Can only get the first values, but loop seems to fail.