I see the use of exportKey in the sample, but I thought that was only needed if I wanted to access the workbook programmatically after it was rendered.
So I am assuming now that the render() call renders the file but does not feed it to the browser. I need to access the file like in the sample using exportKey and send to the browser myself.
For normal use, no exportKey, just redirect to the view
Got it - thank you.
I feel silly - I assumed that the excel export required the use of Renderer.render() the way that email does. I was making it too hard!