Spring Boot 4 Complete Guide · Lesson

Integrating NoSQL Databases

Learn to integrate and interact with NoSQL databases like MongoDB or Redis using Spring Data.

Integrating NoSQL Databases is a free Spring Boot 4 Complete Guide lesson on CoddyKit — lesson 2 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Spring Boot 4 Complete Guide learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.

Intro to NoSQL Databases

Traditional databases (like SQL) store data in structured tables. NoSQL databases offer a flexible alternative, ideal for handling large volumes of unstructured or semi-structured data.

Non-relational: No fixed schema.
Scalable: Easily scale horizontally.
Diverse Models: Document, Key-Value, Graph, Column-Family.

They are great for big data, real-time web apps, and microservices.

Spring Data's Role in NoSQL

Just like with JPA, Spring Data provides a consistent, familiar programming model for interacting with various NoSQL databases.

It simplifies data access by:

Reducing boilerplate code.
Offering repository interfaces.
Handling database-specific operations.

You get the Spring experience even with non-relational stores!

Our NoSQL Example: MongoDB

There are many NoSQL databases, like Redis (key-value), Cassandra (column-family), and Neo4j (graph). For this lesson, we'll focus on MongoDB, a popular document-oriented database.

In MongoDB, data is stored in flexible, JSON-like documents called BSON, grouped into collections.

Add MongoDB Dependency

First, we need to add the Spring Data MongoDB starter dependency to our project. This pulls in all necessary libraries to connect to MongoDB.

For Maven, add this to your pom.xml:

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-data-mongodb</artifactId>
</dependency>

Configure MongoDB Connection

Next, tell Spring Boot how to connect to your MongoDB instance. You'll typically do this in your application.properties or application.yml file.

Here's a basic setup for a local MongoDB:

spring.data.mongodb.host=localhost
spring.data.mongodb.port=27017
spring.data.mongodb.database=mydatabase

Define Your MongoDB Document

In MongoDB, data is stored in documents. We represent these documents in Java using simple POJOs (Plain Old Java Objects). Use Spring Data MongoDB annotations like @Document and @Id.

import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.mapping.Document;

@Document(collection = "products")
public class Product {
  @Id
  private String id;
  private String name;
  private double price;

  public Product(String name, double price) {
    this.name = name;
    this.price = price;
  }

  // Getters and Setters (omitted for brevity)
  public String getId() { return id; }
  public void setId(String id) { this.id = id; }
  public String getName() { return name; }
  public void setName(String name) { this.name = name; }
  public double getPrice() { return price; }
  public void setPrice(double price) { this.price = price; }

  @Override
  public String toString() {
    return "Product{id='" + id + "', name='" + name + "', price=" + price + '}';
  }
}

Create a MongoRepository

Spring Data MongoDB makes interacting with your documents easy through repository interfaces. Extend MongoRepository, specifying your document type and its ID type.

This gives you basic CRUD methods out-of-the-box!

import org.springframework.data.mongodb.repository.MongoRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface ProductRepository extends MongoRepository<Product, String> {
  // Spring Data automatically generates methods based on method names
  Product findByName(String name);
}

Basic CRUD Operations

With MongoRepository, you can perform common operations:

Save: repository.save(product) to insert or update.
Find: repository.findById(id) to get a document by ID.
Find All: repository.findAll() to retrieve all documents.
Delete: repository.deleteById(id) to remove a document.

You can also define custom queries by simply declaring method names!

MongoDB Integration Demo

Let's put it all together! This Spring Boot application saves a product, finds it, and prints its details. Make sure MongoDB is running locally.

import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.mapping.Document;
import org.springframework.data.mongodb.repository.MongoRepository;
import org.springframework.stereotype.Repository;

@SpringBootApplication
public class MongoDemoApplication {

  public static void main(String[] args) {
    SpringApplication.run(MongoDemoApplication.class, args);
  }

  @Bean
  public CommandLineRunner demo(ProductRepository repository) {
    return (args) -> {
      System.out.println("--- MongoDB Demo ---");

      // Clear existing data (optional)
      repository.deleteAll();

      // Save a new product
      Product product1 = new Product("Laptop Pro", 1200.00);
      repository.save(product1);
      System.out.println("Saved: " + product1);

      // Find by name
      Product foundProduct = repository.findByName("Laptop Pro");
      System.out.println("Found by name: " + foundProduct);

      // Find all products
      System.out.println("All products:");
      repository.findAll().forEach(System.out::println);

      System.out.println("--- Demo End ---");
    };
  }

  // Nested Document class
  @Document(collection = "products")
  public static class Product {
    @Id
    private String id;
    private String name;
    private double price;

    public Product(String name, double price) {
      this.name = name;
      this.price = price;
    }

    public String getId() { return id; }
    public void setId(String id) { this.id = id; }
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
    public double getPrice() { return price; }
    public void setPrice(double price) { this.price = price; }

    @Override
    public String toString() {
      return "Product{id='" + id + "', name='" + name + "', price=" + price + '}';
    }
  }

  // Nested Repository interface
  @Repository
  public interface ProductRepository extends MongoRepository<Product, String> {
    Product findByName(String name);
  }
}

Quick Check: NoSQL Repositories

You've seen how Spring Data simplifies NoSQL interactions. Which annotation marks a class as a MongoDB document in Spring Data?

Recap: NoSQL with Spring Data

Great job! You've learned how to integrate NoSQL databases using Spring Data. We covered:

The purpose of NoSQL databases.
Adding the MongoDB starter dependency.
Configuring connection properties.
Creating @Document classes and MongoRepository interfaces.
Performing basic CRUD operations.

Spring Data makes NoSQL as easy to use as traditional SQL databases!

Frequently asked questions

Is the “Integrating NoSQL Databases” lesson free?

Yes — the full text of “Integrating NoSQL Databases” is free to read here on the web, and the Spring Boot 4 Complete Guide course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Spring Boot 4 Complete Guide course, upgrade to CoddyKit PRO.

What will I learn in “Integrating NoSQL Databases”?

Learn to integrate and interact with NoSQL databases like MongoDB or Redis using Spring Data. You practise Spring Boot 4 Complete Guide with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start Spring Boot 4 Complete Guide?

No prior experience is required. Spring Boot 4 Complete Guide on CoddyKit is structured for beginners through advanced learners; this is — lesson 2 of 4, so you can start here or from the beginning and move at your own pace.

How long does the “Integrating NoSQL Databases” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this Spring Boot 4 Complete Guide lesson?

Yes. Every Spring Boot 4 Complete Guide lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

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