Vaadin 8, i have a custom class extends FilterGrid, filled with data, Expor

Directory Exporter
1

Vaadin 8, i have a custom class extends FilterGrid, filled with data, Exporter.exportAsXLS(grid) and i get a totally blank xls.
If i change it to vaadin FilterGrid, then i get “org.vaadin.haijian.ExporterException: No exportable column found, did you remember to set property name as the key for column” while i used setId for all columns.
Why?

2

Could you fix it?