Building a REST API with Spring Boot in Just 15 Minutes

Learn how to build a fully functional REST API in just 15 minutes using Spring Boot. Follow this step-by-step guide to create CRUD operations, manage resources, and set up endpoints efficiently. Perfect for beginners and developers!

TUTORIALJAVASPRINGBOOTREST API

12/25/20244 min read

Introduction to Spring Boot for REST APIs

REST APIs are the backbone of modern web applications.

They allow different systems to communicate seamlessly, enabling dynamic and interactive applications.

Spring Boot, a powerful Java framework, simplifies the process of building RESTful APIs by minimizing boilerplate code and providing a wide range of tools.

Its convention over configuration paradigm allows developers to create production-ready services effortlessly.

In this blog post, we will explore how to build a REST API using Spring Boot in a concise timeframe of only 15 minutes.

What is a REST API?

A REST (Representational State Transfer) API is a web service that adheres to the principles of REST architecture.

It uses standard HTTP methods like GET, POST, PUT, and DELETE to perform operations on resources, which are typically represented in -

JSON or XML format. REST APIs are stateless, scalable, and easy to use, making them a popular choice for modern applications.

What is CRUD?

CRUD stands for Create, Read, Update, and Delete - the four basic operations that can be performed on data. In the context of REST APIs:

Create: Corresponds to the HTTP POST method and is used to add new resources.
Read: Corresponds to the HTTP GET method and is used to retrieve resources.
Update: Corresponds to the HTTP PUT or PATCH method and is used to modify existing resources.
Delete: Corresponds to the HTTP DELETE method and is used to remove resources.

By implementing these operations, a REST API provides a complete interface for interacting with data.

Prerequisites

Before diving into the tutorial, ensure you have the following:

Java Development Kit (JDK): Version 8 or higher.
Maven or Gradle: Build tool for managing dependencies.
An IDE: IntelliJ IDEA, Eclipse, or any text editor of your choice. Download.
Spring Boot Initializr: A tool to bootstrap your project.
Postman : An application for testing REST API. Download.

Step 1: Set Up Your Spring Boot Project

Go to Spring Initializr: Visit Spring Initializer .
Configure the Project:
- Choose Maven Project.
- Select Java as the language.
- Choose the latest version of Spring Boot.
- Add dependencies: Spring Web and Spring Boot DevTools.
- Add the project meta data: Group, Artifact, Name, Description, Package name
Generate the Project: Click on "Generate" to download a ZIP file.
Extract the Project: Unzip the file and open it in your preferred IDE.
[Click the image for full screen view]

Set Up Your Spring Boot Project from Spring Initializr

Step 2: Create a Model Class

The model represents the data structure of your application.Let's create a simple User model.

Create a folder model, create a class User. Refer the code below.

Download Intellij IDEA community Edition - [ a standard editor for back end development]

Your repository after extracting will look like this:

Spring boot REST API Project Folder Structure

Step 3: Create a Repository Class

In a real-world application, you’d use a database. For simplicity, we’ll use a mock repository to store data in memory. Create a folder repository and a class UserRepository.

Why do we need a repository?

Repositories abstract away the underlying database interactions, providing a clean and consistent way to perform CRUD (Create, Read, Update, Delete) operations and queries. Read more.

Step 4: Create a Controller Class

The controller handles HTTP requests and maps them to appropriate methods. Let’s create a folder controller and a class inside it - UserController class to manage User resources.

Step 5: Run the Application

Navigate to the Application class in your project, which should look like this:

Spring boot project Application class open in Intellij IDEA

Run the application using your IDE’s run button or the command line:
mvn spring-boot:run

Also read : Top 10 Spring Boot Features Every Developer Should Know

Step 6: Test Your API

You can test your API endpoints using tools like Postman, cURL, or your browser.

GET /api/users: Retrieve all users.

POSTMAN api testing GET endpoint of REST API in Java Springboot

POST /api/users: Create a new user. Example payload:

POSTMAN api testing POST endpoint of REST API in Java Springboot

GET /api/users/{id}: Retrieve a user by ID.

POSTMAN API testing of REST API in JAVA Spring boot GET endpoint with path parameter

Watch this tutorial video to find out how the code works and how to test in Postman.

Refer this code on Github : Springboot Tutorial

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Conclusion

Building a REST API with Spring Boot is both quick and efficient. In just 15 minutes, you’ve created a fully functional API with endpoints for creating and retrieving user data.

As you grow more familiar with Spring Boot, you can expand this foundation to include features like database integration, authentication, and error handling.

Spring Boot's simplicity and power make it an excellent choice for modern web development. Start building your APIs today and unlock new possibilities for your projects!