Java Webserver W/ Angular Control Panel Web Interface

I have created an application using spring boot that uses angular for the front end and is a basic login portal with encrypted credentials and click verification, what I want to do is have like when someone visits the IP of the server it gets the angular portal, when it’s a domain name, it actually pulls up that website. I want to program this to happen either in java or angular to request the resource from java. How would one go about implementing this? I know how to have java handle http requests and actually get the html to the browser… What I don’t know is how to do that while using the angular front end to act as my control panel.