Put the data in a text file (comma-separated value) then open the file with Excel, this is the easy way.
You can also call a servlet, iterate the list where you have the data and use the POI library (
http://jakarta.apache.org/poi/), to bring the data in a file excel.
Another way is to use the library DisplayTag in your jsp, this is a tag that display the data in a table, give it a list of objects and it will handle column display, sorting, paging, cropping, grouping, exporting, smart linking and decoration of a table in a customizable XHTML style. Take a look to this url
http://displaytag.sourceforge.net/11/ http://displaytag.sourceforge.net/11/export.html