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

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