Java - generate complex excel report

I'm trying change the system of excel generation in a project. Actually, for every report there is an excel template saved on the db, but for every little change I must work for one day, moving all the cell and formulas manually. Unfortunately, is not a simple report like a normale table, is similar to a card with a lot of sub category. Here an example of the report: Example Now, what's the best way to create this kind of report? I try with Jasper, but there's some memory problem and seems not so easy to create. The best way is to pass to the report a bean with all the informations. Many thanks in advance to all of you.

Solution

Of course you may use Apache POI, JExcel API e.t.c. You may create Excel files template and fill data into static template file. But nevertheless it is require a lot of work to creating report.

What problem with memory do you had with Jasper and don't have with POI? Jasper has great feature - Virtualizer which allow to build giant reports on the disk. Also iReport is a very useful tool to build Excel templates. Also, you can create a type of report view in one line.