NUHMAN.com

With the rise of microservices and web-based architectures, RESTful APIs have become the backbone of modern application development. Spring Boot, built on top of the Spring Framework, simplifies the process of creating production-ready REST APIs with minimal configuration.

What Is a RESTful API?

A RESTful API (Representational State Transfer) uses standard HTTP methods (GET, POST, PUT, DELETE) to interact with resources. It’s stateless, scalable, and platform-independent, making it ideal for web and mobile app backends.

Why Spring Boot?

• Quick setup: Minimal boilerplate code.
• Embedded server: Runs independently (Tomcat, Jetty, etc.).
• Production-ready: Includes health checks, metrics, and externalized configuration.
• Spring ecosystem: Seamless integration with Spring Data, Security, etc.

Step-by-Step: Creating a REST API with Spring Boot

1. Create a Spring Boot Project

You can use Spring Initializr to bootstrap a project with dependencies like:

• Spring Web
• Spring Data JPA
• H2 Database (for testing)

2. Define a Model

java

@Entity
public class Product {
    @Id @GeneratedValue
    private Long id;
    private String name;
    private double price;

    // Constructors, Getters, Setters
}

3. Create a Repository

java

public interface ProductRepository extends JpaRepository<Product, Long> {
}

4. Build a REST Controller

java

@RestController
@RequestMapping("/api/products")
public class ProductController {

    @Autowired
    private ProductRepository repository;

    @GetMapping
    public List<Product> getAllProducts() {
        return repository.findAll();
    }

    @PostMapping
    public Product createProduct(@RequestBody Product product) {
        return repository.save(product);
    }

    @GetMapping("/{id}")
    public ResponseEntity<Product> getProductById(@PathVariable Long id) {
        return repository.findById(id)
                         .map(ResponseEntity::ok)
                         .orElse(ResponseEntity.notFound().build());
    }

    @PutMapping("/{id}")
    public Product updateProduct(@RequestBody Product updated, @PathVariable Long id) {
        updated.setId(id);
        return repository.save(updated);
    }

    @DeleteMapping("/{id}")
    public void deleteProduct(@PathVariable Long id) {
        repository.deleteById(id);
    }
}

5. Test the API

You can test endpoints using tools like:

• Postman
• curl
• Swagger UI (via springdoc-openapi)

Best Practices

• Use DTOs to separate API models from database entities.
• Handle exceptions with @ControllerAdvice.
• Validate input using @Valid and @NotNull.
• Secure endpoints with Spring Security.
• Version your API (/api/v1/products).

Spring Boot makes REST API development in Java fast, efficient, and clean. With this foundation, you can scale your application, integrate authentication, and deploy with ease.