Spring Boot + MongoDB REST API Example

This is a basic CRUD API built with Spring Boot and MongoDB. It shows how to:

• Create, read, update, and delete documents in MongoDB
• Use Spring Data MongoDB with MongoRepository
• Add validation with DTOs using Jakarta Bean Validation
• Return clean, shaped API responses

Prerequisites

• Java 21
• Maven 3.9+
• MongoDB running locally or a MongoDB Atlas URI

How to Run

1. Clone the project
2. Set your MongoDB URI in src/main/resources/application.properties:

spring.data.mongodb.uri=YOUR\_CONNECTION\_STRING
spring.data.mongodb.database=library

3. Start the application:

mvn spring-boot:run

4. Test the API with curl, Postman, or HTTPie.

Example POST:

curl -X POST http://localhost:8080/api/books \
  -H "Content-Type: application/json" \
  -d '{"title": "Dune", "author": "Frank Herbert"}'

Project Structure

• Book: The domain model
• BookRequest: Input DTO with validation
• BookResponse: Output DTO for shaping API responses
• BookRepository: Spring Data MongoDB repository
• BookController: REST controller