How to make a simple REST API server?

Question

Java

Good present, friends.
My task is to make a simple RESTful server. It is necessary that on POST it saves the transmitted data to a database or file, and on GET it returns data from the table according to the key being sent.
I know Java, but I was told that on node.js or django this is done in 15 lines. Tried to figure it out, but it doesn't work. Tell me, please, where can I see an accessible explanation, so that it would be without unnecessary difficulties.
Many thanks in advance for your advice.

Answer 1

You need to google for Spring Boot REST Crud
Example

Answer 2

Use spark or analogues, it is also done there in 15 lines

Answer 3

Chrome spark I recommend ratpack.io - there are both for Java and for groovy