Synchronization between Java Application and Microsoft Application via Jacob

Question

In my java application I am connecting to Microsoft Excel with Jacob libraries. Everything is fine but I do not know how I can catch com events when any changes in Excel page occurs by using Jacob libraries. For example, In my project I connect database takes table values and copy these values into cells of an excel page. Whenever a cell value is changed, the table value is also changed. That's I want synchronization between java and Microsoft Excel application by Jacob.

Answer 1

Don't use Java to achieve that. See this question: Excel OnChange event, with emphasis on this answer. You should access your database using com directly from Excel. That's easy using ADO. This ADO tutorial from w3schools looks also fine.

If the task is too complex to perform directly from Excel you may think of putting a small marker somewhere (e.g. in the database) that the data changed and process this marker from other app, possibly java app. The difficulty is that the credentials to access the database must be hardcoded in the Excel sheet. But you can create a separate database user with narrow database permissions.

Seeing your comment I also tried using Change event of Excel to detect changes done by other users. My experience on Excel 2003 shows that this works only locally. That is the event is fired only for the user that made the change. If many users have the worksheet open they don't receive Change event caused by changes from other users. So your approach is unfeasible. You may test it with Excel 2010, but my impression is that the events in general work only locally. Couldn't find anything on the net about it. Only this general article: Track changes in a shared workbook.