@Override
            public String formatNumberDateCell(CellValueRecordInterface cell) {
                String formatString = this.getFormatString(cell);

                double value;
                if (cell instanceof NumberRecord) {
                    value = ((NumberRecord) cell).getValue();
                } else {
                    if (!(cell instanceof FormulaRecord)) {
                        throw new IllegalArgumentException(
                                "Unsupported CellValue Record passed in " + cell);
                    }
                    value = ((FormulaRecord) cell).getValue();
                }
                if (DateUtil.isADateFormat(getFormatIndex(cell), formatString)) {
                    return tikaExcelDataFormatter
                            .formatRawCellContents(value, getFormatIndex(cell), formatString,
                                    false);
                } else if ("general".equalsIgnoreCase(formatString)) {
                    return tikaExcelDataFormatter
                            .formatRawCellContents(value, getFormatIndex(cell), formatString,
                                    false);
                }
                return super.formatNumberDateCell(cell);
            }
Process an excel sheet.

@throws SAXException if an error occurs
tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-microsoft-module/src/main/java/org/apache/tika/parser/microsoft/ExcelExtractor.java