@Override
    public Long convertToJavaData(ReadCellData<?> cellData, ExcelContentProperty contentProperty,
                                  GlobalConfiguration globalConfiguration) throws ParseException {
        return NumberUtils.parseLong(cellData.getStringValue(), contentProperty);
    }
Long and string converter

@author Jiaju Zhuang
fastexcel-core/src/main/java/cn/idev/excel/converters/longconverter/LongStringConverter.java