Is there any example of creating and downloading reports Jmix specific style?

Is there any projects with examples how I can export some DTO object to csv (or xls) file and download it in Jmix specific way?
I found some information about creating Excel reports in Jmix documentation in an add-ons section. but it’s not enough for me.
Also there is an Export button in PetClinic project, but it doesnt work (I’ve got NullPointerException by pressing it).
Or may be there are no Jmix specific solutions and I can do it on Spring Boot?

Found a solution. It’s very simple.
Just add Excel export button in your screen .xml file
In actions:

                <action id="excel" caption="Export" type="excelExport" icon="font-icon:SAVE"/>

The type must be “excelExport” because it’s defined in Jmix.
In buttonsPanel:

                <button action="YourTableName.excel"/>

That’s it! There is an Export button on page. Click it and repot starts downloading.