Spring Boot Example

The simple Spring Boot example that demonstrates the creation of a RESTful web service with a single endpoint that returns “Hello, World!” as a response. This example assumes you have Spring Boot and a development environment (e.g., Java and an Integrated Development Environment) set up.

Step 1: Create a Spring Boot Project

You can create a Spring Boot project using the Spring Initializr or your preferred IDE. Here’s how to do it using the Spring Initializr:

1. Visit the Spring Initializr web page at https://start.spring.io/.
2. Configure your project by selecting “Maven Project” or “Gradle Project,” choosing the language (Java or Kotlin), and setting the Spring Boot version.
3. Define your project’s metadata (e.g., Group, Artifact, Package name).
4. Add the “Spring Web” dependency from the “Dependencies” section.
5. Click the “Generate” button to download the project as a ZIP file.

Step 2: Set Up Your Project in an IDE

If you’re using an IDE like IntelliJ IDEA or Eclipse, import the project by opening the downloaded ZIP file. If you’re using a text editor, extract the ZIP file to your desired directory.

Step 3: Write the Spring Boot Code

Create a new Java class, e.g., HelloController.java, in your project’s source code directory (usually src/main/java/com/example/demo) with the following code:

package com.example.demo;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HelloController {

    @GetMapping("/hello")
    public String sayHello() {
        return "Hello, World!";
    }
}

In this code:

• @RestController annotation marks the class as a Spring MVC controller, indicating that it will handle HTTP requests and return data as JSON.
• @GetMapping("/hello") maps the /hello URL path to the sayHello() method.
• sayHello() is a simple method that returns the “Hello, World!” string.

Step 4: Run the Application

You can run your Spring Boot application using your IDE or from the command line. To run it from the command line, open a terminal, navigate to your project directory, and use the following command (Maven example):

mvn spring-boot:run

Step 5: Access the Hello World Endpoint

Open a web browser or use a tool like curl to access the “Hello World” endpoint:

• Open a web browser and go to http://localhost:8080/hello (assuming your application is running on the default port).
• You should see the “Hello, World!” message displayed in your browser.

That’s it! You’ve created a simple Spring Boot application that serves a “Hello, World!” message via a RESTful web service. This is a basic example, and Spring Boot can be used to build much more complex and feature-rich applications with ease.