calling java classes's methods to return an excel file

[chessmonster]

good day, i am trying to setup a simple reporting scheme, from the request on the widget and then the controller then to the java class then it should return the excel file which contains the information of the requested report using apache poi. that is the plan, but I see it as a bit of a challenge due to the things that I need to setup to make this work. I was wondering if you could help me out by giving out some links or the topics that I need to read because this is a big elephant that would really take time to consume. I am just not sure which specific topics I need to be knowledgeable with.

[chessmonster]

i will just plan to create an excel file on a java method callable by a controller, then outputting the file to a specified directory.

noobie error, I did not used the build file of the web-app that I am working on but I kept on using the build file of the whole ofbiz that is why the changes that I did on the webapp that I am doing are not working