Spring Boot REST Example

Creating a simple RESTful API using Spring Boot is a common task. Here, I’ll provide you with a step-by-step guide to create a basic Spring Boot RESTful web service. We’ll create an endpoint that handles HTTP GET requests and returns a list of items.

Step 1: Create a Spring Boot Project

You can create a Spring Boot project using Spring Initializr or your preferred development environment.

Step 2: Define a Model Class

Create a model class that represents the data you want to expose through your API. For this example, let’s create a Product class:

public class Product {
    private Long id;
    private String name;
    private double price;

    // Constructors, getters, and setters
}

Step 3: Create a Controller

Create a controller class that defines the REST endpoints. In this case, we’ll create an endpoint to retrieve a list of products.

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

    @GetMapping
    public List<Product> getAllProducts() {
        // Replace this with code to fetch a list of products from a database or elsewhere
        List<Product> products = new ArrayList<>();
        products.add(new Product(1L, "Product 1", 19.99));
        products.add(new Product(2L, "Product 2", 29.99));
        return products;
    }
}

In this example, we’ve defined a controller with a @GetMapping annotation that maps to the /api/products URL. It returns a list of Product objects.

Step 4: Run Your Application

Run your Spring Boot application. By default, Spring Boot applications usually run on port 8080. You can access your REST API at http://localhost:8080/api/products.

Step 5: Test Your REST API

You can use tools like curl, Postman, or write a simple web client to test your REST API. To test it in a web browser, simply enter the URL http://localhost:8080/api/products, and you should see a JSON response with a list of products.

Here’s an example of what the JSON response might look like:

[
    {
        "id": 1,
        "name": "Product 1",
        "price": 19.99
    },
    {
        "id": 2,
        "name": "Product 2",
        "price": 29.99
    }
]

That’s it! You’ve created a basic Spring Boot RESTful API. This example serves as a starting point, and you can extend it to handle more complex operations, such as creating, updating, and deleting resources, and connect it to a database for data persistence.