Spring Boot api authentication - oauth

Api authentication task:

I have a task where my api needs to authenticate by oauth access token.

Api1 will call /api2/gettoken to get the new token
Once I get token it needs to save in the application somewhere for later calls until it expires.
Then Api1 will call /api2/postdata with this new token in the request.
If token is expired then we need to call /api2/gettoken again to get fresh token and repeat the same.

There is no work on the api2 part. It's completed and working fine.
I just need someone who has done this before to have quick implementation.

Let me know if you have any questions