BigDecimal Type Problem

[baocaixue]

Hi, millij. I have a pojo, and it have BigDecimal field. But, if this field in excel is empty, that got a Exception of :

org.apache.commons.beanutils.ConversionException: No value specified for 'BigDecimal'
	at org.apache.commons.beanutils.converters.AbstractConverter.handleMissing(AbstractConverter.java:328)
	at org.apache.commons.beanutils.converters.AbstractConverter.convert(AbstractConverter.java:149)
	at org.apache.commons.beanutils.converters.ConverterFacade.convert(ConverterFacade.java:61)
	at org.apache.commons.beanutils.BeanUtilsBean.convert(BeanUtilsBean.java:1079)
	at org.apache.commons.beanutils.BeanUtilsBean.setProperty(BeanUtilsBean.java:1012)
	at org.apache.commons.beanutils.BeanUtils.setProperty(BeanUtils.java:454)
	at io.github.millij.poi.util.Spreadsheet.rowAsBean(Spreadsheet.java:186)
	at io.github.millij.poi.ss.handler.RowContentsHandler.afterRowEnd(RowContentsHandler.java:73)

And i think that it should be null if excel field is empty.