Showing posts from October, 2010

f:convertNumber parses to double not BigDecimal

The default behaviour of the f:convertNumber, implemented with NumberConverter, in converting a decimal String of "1.11", is to convert it to a double and then JSF converts that to a BigDecimal. Most of the time you won't notice this happening until you use CallableStatement.setBigDecimal to invoke a stored procedure. In MS SQL Server, you get the following error: Error converting data type nvarchar to decimal.The cause of this is because inside the BigDecimal it stored "1100000000000000976996261670137755572795867919921875" as a result of converting the String to a double. This floating point error is the motivation for using BigDecimal in the first place. And of course because the SQL Server JDBC driver didn't know how to handle the BigDecimal properly.

Looking into ConvertNumber, it uses one of two converters (DecimalFormat or NumberFormat) depending on whether 'pattern' is used. In Java 5, they adde…