Spring Boot MongoDB - Simple App Tutorial

Sebelumnya kita membuat "Belajar MongoDB Dasar Menggunakan MongoDB Compass (Aman untuk Amazon DocumentDB)" https://undebugable.blogspot.com/2026/01/belajar-mongodb-dasar-menggunakan.html.

Step 1 – Buat Project Spring Boot

Opsi A (Recommended): Spring Initializr (Web)

Buka https://start.spring.io

Project Settings

• Project: Gradle

• Language: Java

• Spring Boot: 3.x

• Java: 17

Project Metadata

• Group: com.yusuf

• Artifact: spring-mongo-clean

• Name: spring-mongo-clean

• Package name: com.yusuf.springmongoclean

• Packaging: Jar

Dependencies

• Spring Web
• Spring Data MongoDB

Klik Generate → Extract → Open di IntelliJ

Step 2 – Struktur Project (Clean dari Awal)

Setelah dibuka di IntelliJ, rapikan package:

src/main/java/com/yusuf/springmongoclean
│
├── SpringMongoCleanApplication.java
│
├── config
│   └── MongoConfig.java   (nanti)
│
├── controller
│   └── UserController.java
│
├── service
│   └── UserService.java
│
├── repository
│   └── UserRepository.java
│
├── domain
│   └── User.java
│
└── dto
    └── UserRequest.java

Kenapa ini clean?

• Controller = HTTP

• Service = business logic

• Repository = data access

• Domain = entity

• DTO = request/response (tidak bocor entity)

Step 3 – Konfigurasi MongoDB (application.yml)

Buka src/main/resources/application.yml

server:
  port: 8080

spring:
  application:
    name: spring-mongo-clean
  mongodb:
    uri: ${MONGO_CONNECTION_STRING:mongodb://root:root@localhost:27017/auth_db?authSource=admin}

logging:
  level:
    org.mongodb.driver: DEBUG
    com.yusuf.springmongoclean: DEBUG

Step 4 – Domain Model (Clean & Modern)

domain/User.java

Gunakan Record (Java 17+)

package com.yusuf.springmongoclean.domain;

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

@Document(collection = "users")
public record User(
        @Id String id,
        String name,
        String email
) {}

Step 5 – Repository (Spring Data MongoDB)

repository/UserRepository.java

package com.yusuf.springmongoclean.repository;

import com.yusuf.springmongoclean.domain.User;
import org.springframework.data.mongodb.repository.MongoRepository;

import java.util.Optional;

public interface UserRepository extends MongoRepository<User, String> {

    Optional<User> findByEmail(String email);
}

*No implementation needed (Spring auto-generate).

Step 6 – Service Layer (Clean Logic)

service/UserService.java

package com.yusuf.springmongoclean.service;

import com.yusuf.springmongoclean.domain.User;
import com.yusuf.springmongoclean.repository.UserRepository;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class UserService {

    private final UserRepository repository;

    public UserService(UserRepository repository) {
        this.repository = repository;
    }

    public User create(String name, String email) {
        repository.findByEmail(email)
                .ifPresent(user -> {
                    throw new IllegalArgumentException("Email already exists");
                });

        return repository.save(new User(null, name, email));
    }

    public List<User> findAll() {
        return repository.findAll();
    }
}

Clean Code check:

• Fungsi kecil

• Tidak ada side effect tersembunyi

• Validasi jelas

Step 7 – DTO (Jangan Langsung Pakai Entity)

dto/UserRequest.java

package com.yusuf.springmongoclean.dto;

public record UserRequest(
        String name,
        String email
) {}    

Step 8 – Controller (REST API)

controller/UserController.java

package com.yusuf.springmongoclean.controller;

import com.yusuf.springmongoclean.domain.User;
import com.yusuf.springmongoclean.dto.UserRequest;
import com.yusuf.springmongoclean.service.UserService;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
@RequestMapping("/users")
public class UserController {

    private final UserService service;

    public UserController(UserService service) {
        this.service = service;
    }

    @PostMapping
    public User create(@RequestBody UserRequest request) {
        return service.create(request.name(), request.email());
    }

    @GetMapping
    public List<User> findAll() {
        return service.findAll();
    }
}

Step 9 – Run & Test

Run:

Step 10 – Test di Postman

Curl:

postman request POST 'http://localhost:8080/users' \

  --header 'Content-Type: application/json' \

  --body '{

  "name": "Yusuf3",

  "email": "yusuf3@gmail.com"

}'