Building REST APIs in Fullstack Java with Spring Boot and MongoDB

In today’s modern web development landscape, building robust and scalable backend systems is just as important as delivering stunning front-end experiences. Java, known for its reliability and performance, continues to be a popular choice for building enterprise-grade applications. When combined with Spring Boot and MongoDB, Java becomes a powerful stack for creating efficient and flexible REST APIs in fullstack applications.

In this blog, we’ll walk through the process and benefits of building RESTful APIs using Spring Boot and MongoDB, and how they fit into a fullstack architecture.

Why Spring Boot and MongoDB?

Spring Boot simplifies the setup and development of Java applications by providing default configurations, dependency management, and built-in tools for building REST APIs quickly.

MongoDB, a NoSQL database, stores data in flexible, JSON-like documents, making it ideal for dynamic applications that require scalability and high availability.

This tech stack allows fullstack developers to rapidly build and iterate both front-end and back-end components.

Setting Up Your Spring Boot Project

To begin, create a Spring Boot project using Spring Initializr (https://start.spring.io). Include the following dependencies:

Spring Web

Spring Data MongoDB

Spring Boot DevTools

Lombok (optional for reducing boilerplate)

Once your project is generated and opened in your IDE (like IntelliJ or Eclipse), configure MongoDB connection in the application.properties:

properties

spring.data.mongodb.uri=mongodb://localhost:27017/mydb

Creating the REST API Structure

1. Define the Model

java

import org.springframework.data.annotation.Id;

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

@Document(collection = "users")

public class User {

    @Id

    private String id;

    private String name;

    private String email;

    // Getters and Setters

}

2. Create the Repository

java

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

public interface UserRepository extends MongoRepository<User, String> {

}

This interface provides built-in CRUD operations.

3. Build the Controller

java
import org.springframework.web.bind.annotation.*;
import java.util.List;
@RestController
@RequestMapping("/api/users")
public class UserController {
    private final UserRepository userRepository;
    public UserController(UserRepository userRepository) {
        this.userRepository = userRepository;
    }
    @GetMapping
    public List<User> getAllUsers() {
        return userRepository.findAll();
    }
    @PostMapping
    public User createUser(@RequestBody User user) {
        return userRepository.save(user);
    }
    @GetMapping("/{id}")
    public User getUserById(@PathVariable String id) {
        return userRepository.findById(id).orElse(null);
    }
    @PutMapping("/{id}")
    public User updateUser(@PathVariable String id, @RequestBody User userDetails) {
        User user = userRepository.findById(id).orElse(null);
        if (user != null) {
            user.setName(userDetails.getName());
            user.setEmail(userDetails.getEmail());
            return userRepository.save(user);
        }
        return null;
    }
    @DeleteMapping("/{id}")
    public void deleteUser(@PathVariable String id) {
        userRepository.deleteById(id);
    }
}

With just a few lines of code, you’ve built a full REST API that can:

Create users

Retrieve all users

Get a user by ID

Update user details

Delete users

Connecting Front-End (Fullstack Integration)

For a complete fullstack setup, you can connect this backend to a front-end built with React, Angular, or Vue. Use axios or fetch() to call the above endpoints (/api/users) from your UI, and you'll have a fully functional CRUD application.

Final Thoughts

Using Spring Boot and MongoDB, building REST APIs in Java has never been more accessible or efficient. This combination provides the scalability of NoSQL with the power of Java’s mature ecosystem. Whether you're working on a personal project or an enterprise application, this stack can handle everything from simple APIs to complex, distributed systems.

 Learn FullStack Java Course in Hyderabad

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