val file = File("/home/user/file.xlsx")
val opcPackage = OPCPackage.open(file)
val workbook = XSSFWorkbook(opcPackage)

workbook.getSheet("Sheet1").rowIterator().forEach { row ->
  row.cellIterator().forEach { cell ->
    when (cell.cellTypeEnum) {
      CellType.STRING -> print("${cell.stringCellValue}\t")
      CellType.NUMERIC -> print("${cell.numericCellValue}\t")
      else -> print("")
    }
  }
}