Problem to read formulas using Apache POI

I'm creating a method to hide elements that are zeroed out of an excel file, but the problem is that it can not pick up the values when the column is a formula. How can I get these values?

My code:

private static ByteArrayOutputStream ocultarZerados(ByteArrayOutputStream arquivo) throws Exception
{
    InputStream arquivoExcel = new ByteArrayInputStream(arquivo.toByteArray());
    XSSFWorkbook wb = new XSSFWorkbook(arquivoExcel);


    XSSFSheet s = (XSSFSheet) wb.getSheetAt(1);

    for (Row linha : s)
    {
        System.out.println("===================");

        for (Cell coluna : linha)
        {
            if(coluna.getCellType() == 1)
            {
                System.out.print(coluna.getStringCellValue() + "|");
            }
            else {
                System.out.print(coluna.getNumericCellValue() + "|");
            }
        }

        System.out.println("===================");
    }

    wb.write(arquivo);
    wb.close();

    return arquivo;
}