Connect MongoDB to Spring Boot

Learn how to integrate MongoDB with Spring Boot to store and retrieve data easily using Spring Data MongoDB.

1. Prerequisites

Java 11 or higher
Maven or Gradle
MongoDB installed locally or a MongoDB Atlas cluster
Basic knowledge of Spring Boot

2. Add Dependencies

Add the following dependency in your pom.xml :

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

3. Configure application.properties

For a local MongoDB instance:

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

For a MongoDB Atlas cluster:

spring.data.mongodb.uri=mongodb+srv://<username>:<password>@<cluster-url>/mydatabase?retryWrites=true&w=majority

4. Create Model and Repository

Model (User.java):

package com.example.demo.model;
 
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
    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 String getEmail() { return email; }
    public void setEmail(String email) { this.email = email; }
}

Repository (UserRepository.java):

package com.example.demo.repository;
 
import com.example.demo.model.User;
import org.springframework.data.mongodb.repository.MongoRepository;
 
public interface UserRepository extends MongoRepository<User, String> {
    User findByEmail(String email);
}

5. Create a REST Controller

Controller (UserController.java):

package com.example.demo.controller;
 
import com.example.demo.model.User;
import com.example.demo.repository.UserRepository;
import org.springframework.web.bind.annotation.*;
 
import java.util.List;
 
@RestController
@RequestMapping("/api/users")
public class UserController {
 
    private final UserRepository repo;
 
    public UserController(UserRepository repo) {
        this.repo = repo;
    }
 
    @GetMapping
    public List<User> getAll() {
        return repo.findAll();
    }
 
    @PostMapping
    public User create(@RequestBody User user) {
        return repo.save(user);
    }
 
    @GetMapping("/{email}")
    public User getByEmail(@PathVariable String email) {
        return repo.findByEmail(email);
    }
}

6. Run and Test

Start MongoDB locally:

mongod

Then run the Spring Boot app:

mvn spring-boot:run

Test endpoints:

GET http://localhost:8080/api/users
POST http://localhost:8080/api/users (with JSON body)

Example body:

{
  "name": "Akshay",
  "email": "akshay@example.com"
}

7. Next Steps

Add validation using @Valid
Use DTOs for request/response objects
Deploy with MongoDB Atlas in production
Secure endpoints using Spring Security

That’s it! 🎉 You’ve successfully connected MongoDB with Spring Boot using Spring Data MongoDB.

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