Here is the sample code for performing this operation using poi api and also preparing a document for the guidance. Tomorrow the document will be uploaded as well, it will guide better in using this sample code.
The code is having comments which are explanatory and understandable.
Presently the code is in the assetmaint under special purpose.
The spreadsheet is also attached. Put this file in your OfbizHomeDirectory/spreadsheet and don't forget to import the data for scheduling the job. The data is in the file ScheduleUploadJob.xml.
Thanks & Regards,