1) Ensure I only save relevant sheets/cells from the files (to speed up retrieval/parsing) 2) Override parsing in XSSFWorkbook to avoid unnecessary work such as themes, styles etc 3) Pool the workbooks to avoid creating them every time (even though I need to be able to update them separately for every request) 4) Something else :-)
I don't know about #1. Personally, I just save the output values, not the sheets. #2 seems like a whole lot of work, especially compared to #3. #3 is what I do: Load the workbook on first request and re-use for subsequent requests. If you know in advance what cells may be changed, you can cache those values when you first load a workbook. Then you hand the workbook out to a consumer, with the understanding that only those input values are changed. When done you restore the inputs to their original values. (And, in my case, I re-evaluate the workbook at that point, to restore things as much as possible.) #4? Well, profiling is good. A lot of times you think your bottleneck is one thing and it turns out to be something unexpected entirely. ===Blake===
