Examples

Kotlin Spring Boot API

Building a Spring Boot API

Kotlin Spring Boot API handles REST with typed endpoints.

Introduction to Kotlin Spring Boot

Spring Boot is a powerful framework for building web applications in Java and Kotlin. Using Kotlin with Spring Boot enhances productivity with a concise syntax and powerful type system.

This tutorial will guide you through creating a REST API using Kotlin and Spring Boot with typed endpoints.

Setting Up the Kotlin Spring Boot Project

First, ensure you have Java 11 or newer and IntelliJ IDEA installed. Then, create a new Spring Boot project using Spring Initializr:

  • Navigate to Spring Initializr.
  • Select Kotlin as the language, and add dependencies such as Spring Web and Spring Boot DevTools.
  • Generate the project and open it in IntelliJ IDEA.

Creating a REST Controller

Let's create a simple REST controller to handle HTTP requests. This controller will respond to requests at the /api/greetings endpoint.

Understanding Typed Endpoints

Typed endpoints in Kotlin provide compile-time safety by ensuring that the request parameters and response types are strictly defined. In our example, the greet function uses @RequestParam to define a query parameter, ensuring it is a String.

This approach reduces runtime errors and improves code readability.

Running the Application

To run the application, use the Spring Boot run configuration in IntelliJ IDEA or execute the following command in your terminal:

Once the application is running, you can test the API endpoint by visiting http://localhost:8080/api/greetings?name=YourName in your web browser. You should see a greeting message.