问题
I have an editable Primefaces Datatable configured to call an onCellEdit() method when a cell is edited. Everything works great except that CellEditEvent.rowKey is always null in spite of setting it explicitly to a valid value in the Datatable declaration with 'rowKey='. The Primefaces Datatable documentation leads me to believe that I need the rowKey to get the contents of the row containing the cell being edited. I need the entire row's contents so I can compare the displayed data with the same data in the database to determine if the persisted data had been changed by another client since the Datatable was rendered, catching concurrent edits.
回答1:
After reading a dozen or more posts on the rowKey being null with row-selectable Datatables I finally realized that rowKey is populated on row select, not on cell edit. rowIndex, however, is not null on cell edit, and reliably gives me the row number (zero-based) so I can retrieve the entire row's contents, and the values of the object used to populate the row (which in my case includes the value I wanted to put into rowKey) from Datatable.getValue(). The purpose of rowKey is not clear in the documentation (to me), so I thought I would share this for anyone encountering a similar problem.
回答2:
The root cause has been explained by @snakedog already. I will add the code for remedying the issue.
Here is the attribute that you should put within p:datatable:
selectionMode="single"
If you do not want the selection highlight to be seen visually, add disabledSelection="true" as well.
来源：https://stackoverflow.com/questions/44790692/editable-datatable-rowkey-null