Introduction

In this practical, you will work through the basics of creating a microservice using Micronaut.

What you should already know

You should be able to:

• Create your own classes in the Java programming language.
• Be familiar with inheritance and implementing interfaces.
• Add annotations to classes, methods, parameters, and variables (e.g. @Override on a method).
• Use generics to parameterize types (e.g. List<Integer>).
• Use lists and maps from the Java Collections Framework.
• Write unit tests using JUnit.

If you need to read up on these concepts, consult the links in the Part 1 Java knowledge map in the VLE, and check the Learn Java section of the Dev.java website.

You should be familiar with these concepts from the lectures:

• The definition of software architecture as structure + architectural characteristics + decisions + design principles.
• The microservices architectural pattern.
• The REST principles and the 4 levels of the Richardson Maturity Model.

What you will learn

• How to create a new Micronaut project from scratch.
• How to import the project into IntelliJ.
• How to write controllers that handle HTTP requests in JSON format.
• How to produce a web-based interface to try out the controllers.
• How to write unit tests for the controllers.

What you will need

• Java 17 or newer: install from Adoptium.
• An IDE with Gradle and Java support: in this worksheet, we discuss IntelliJ IDEA.

What you will do

You will implement and test a minimal version of a microservice which manages a collection of books. The microservice will be able to create, retrieve, update, and delete books.