Building a Simple Microservice

In this section, we will focus on building a simple microservice using Spring Boot. Our microservice will have a REST API endpoint that returns a simple "Hello, World!" message.

To get started, we need to create a new Java class that will serve as our controller. The controller will define the routes and handle the incoming HTTP requests. Let's create a new class called HelloController:

1${code}

In the code snippet above, we have defined a HelloController class with a sayHello method. This method is annotated with @GetMapping("/hello"), which specifies that it should handle the GET requests to the "/hello" route. Inside the method, we simply return the string "Hello, World!".

Once we have the controller in place, we need to configure our microservice to run. We can do this by creating a main method in a separate class, such as Application, and starting a Spring Boot application context:

1public class Application {
2  public static void main(String[] args) {
3    SpringApplication.run(Application.class, args);
4  }
5}

In the main method above, we are using SpringApplication.run to start the Spring Boot application. We pass Application.class as the first argument, which indicates the primary configuration class for our application.

That's it! We have now created a simple microservice with a REST API endpoint. Next, we will learn how to test our microservice and make HTTP requests to it.

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class HelloController {

  @GetMapping("/hello")

  public String sayHello() {

    return "Hello, World!";

  }

}