Article 03: Creating Your First Microservice with Spring Boot

1. Objective

Build your first standalone microservice using Spring Boot and understand its structure.

2. Key Concepts

• Spring Boot fundamentals
• RESTful APIs
• Controller, Service, Repository layers
• Embedded server

3. What Is a Microservice in Practice?

A microservice is:

• Independently deployable
• Focused on one business capability
• Owns its data

4. Project Setup

Tools required:

• JDK 17+
• Maven
• IDE (IntelliJ / Eclipse)

Dependencies:

• Spring Web
• Spring Data JPA
• H2 / PostgreSQL

5. Hands-On: Create User Service

Service responsibilities:

• Create user
• Get user
• Update user

Package structure:

com.example.userservice
 ├── controller
 ├── service
 ├── repository
 └── model

6. Sample Controller

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

    @GetMapping("/{id}")
    public String getUser(@PathVariable Long id) {
        return "User " + id;
    }
}

7. application.yml

server:
  port: 8081
spring:
  application:
    name: user-service

8. Common Mistakes

• Mixing business logic in controllers
• Treating microservice like a monolith
• Hardcoding configurations

9. Interview Notes

• Each microservice should be independently deployable
• Spring Boot reduces boilerplate significantly

10. Summary

You now have a standalone microservice running independently.

11. What’s Next

Run multiple microservices together and manage configurations.