Among alot of other data I am trying to make some of the cells with dates and have done it as suggested in the "Developers' Guide to HSSF and XSSF Features". I make a new cellstyle and change dataformat. Everything is shown as I want when opening the file with Excel 2007. For instance if I use dd.mm.yyyy or dd/mm/yyyy the output will be for instance 22/11/2010. When setting cellValue I have tried with both Calendar and Date as input.
The problem is the format of the cell is shown as "User Defined" instead of "Date". My output file is going to be converted by another program and it expects it as a "Date". It is alot of data so I doing it manually would be too time consuming. Any ideas if this is possible and if so what I am doing wrong? -Ole.
