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SpringBoot Lab

The goal here is to create a sample micro service coded in Java Spring Boot built with Maven.

  1. Create the micro service using Spring Initializr online tool.

    Warning

    Don't forget to add "Spring Web" dependency !

    Spring Initializr Settings

    • Click on "Generate" to download the zipped sources.

    • Extract them in your work directory.

    • Import it in your favorite Java IDE as a Maven project.

      Tip

      IntelliJ Idea Community Edition is a very good choice ... Just saying !

      Tip

      If you don't use IntelliJ and need to install Maven, here is the command 😉 

      1
      choco install maven

  2. Edit the code

    • Modify the main class :

      src/main/java/com/yncrea/cloudcomputing/CloudcomputingApplication.java

      as below :

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      package com.yncrea.cloudcomputing;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

@RestController
@SpringBootApplication
public class CloudcomputingApplication {

    @RequestMapping("/")
    public String home() {
        String hostname = System.getenv("HOSTNAME");
        return "Hello Docker World - hostname : " + hostname;
    }

    @RequestMapping("/hello")
    @ResponseBody
    public String sayHello() {
        return "Hello " + System.getenv("GREETING");
    }

    @RequestMapping("/secret")
    @ResponseBody
    public String getSecret() {
        String secret = System.getenv("MY_SECRET") == null ? "" : System.getenv("MY_SECRET");
        return "Secret : " + secret;
    }

    public static void main(String[] args) {
        SpringApplication.run(CloudcomputingApplication.class, args);
    }

}

  3. Test it with the embedded Tomcat Server

    • Build the project using your IDE Maven Window

      or

      Using the command line : 

      1
      mvn clean install

    • Run the application using your IDE Run Configuration

      or

      Using the command line : 

      1
      mvn spring-boot:run

    • The application is now accessible at http://localhost:8080

      Tip

      Try visiting http://localhost:8080/hello to reach your 2nd API 😏