Spring Boot Backend Development Course, Deploying Our Service with AWS Services

In recent years, the Java-based framework Spring Boot has gained popularity in the field of backend development. Spring Boot focuses on simplifying configuration and enhancing productivity, helping developers build applications more quickly and efficiently. Additionally, advancements in cloud services have opened an era where we can easily deploy our services. In particular, AWS (Amazon Web Services) provides various cloud services and features to support the flexible operation of backend applications. This course will detail the process of developing a simple backend application using Spring Boot and deploying it to AWS.

1. Introduction to Spring Boot

Spring Boot has the motto of ‘doing a lot with minimal configuration’. Traditional Spring Framework required a lot of setup and configuration, but Spring Boot supports developers by automatically configuring these settings. As a result, we are provided with an environment where we can focus on business logic.

Features of Spring Boot
- Autoconfiguration: Spring Boot provides most functionalities with its default configurations.
- Starter Dependencies: Provides necessary libraries as starter dependencies for easy use.
- Embedded Server: Reduces deployment complexity by including servers like Tomcat and Jetty.
- Production Ready: Spring Boot offers several features necessary for monitoring and management by default.

2. Setting Up the Spring Boot Development Environment

To develop a Spring Boot application, you must first have the Java Development Kit (JDK) installed. Also, IDEs (Integrated Development Environments) like IntelliJ IDEA, Eclipse, and VS Code are recommended. In this course, we will explain using IntelliJ IDEA as the basis.

Install JDK
After installing the JDK, set the JAVA_HOME environment variable. To download the latest version of the JDK, visit the Oracle official website or OpenJDK.
Install IDE
Download and install IntelliJ IDEA. After installation, complete the basic settings.
Create a Spring Boot Project
Run IntelliJ IDEA, select “New Project”, and choose “Spring Initializr” to create a new Spring Boot project.

3. Configuring the Spring Boot Project

When creating a Spring Boot project, you can select the desired package structure and necessary dependencies. The commonly used dependencies are as follows:

Spring Web: Library for developing RESTful APIs
Spring Data JPA: Library for database integration
H2 Database: In-memory database suitable for practice

3.1 Basic Application Configuration

After the project is created, you can open the application.properties file and add basic settings. For example, if you want to change the port number settings, you can set it as follows:

server.port=8080

3.2 Create Entity Class

In this course, we will create a simple note (or to-do) management application. Let’s create the entity class as follows:

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity
public class Todo {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String title;
    private boolean completed;

    // Getter and Setter methods
}

3.3 Create Repository Interface

Use Spring Data JPA to create a repository interface that can interact with the database:

import org.springframework.data.jpa.repository.JpaRepository;

public interface TodoRepository extends JpaRepository {
}

3.4 Create Service Class

Write a service class that will handle business logic:

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class TodoService {
    @Autowired
    private TodoRepository todoRepository;

    public List getAllTodos() {
        return todoRepository.findAll();
    }

    public Todo createTodo(Todo todo) {
        return todoRepository.save(todo);
    }
}

3.5 Create REST API Controller

Finally, create a controller class that provides the REST API interface for this application:

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
@RequestMapping("/api/todos")
public class TodoController {
    @Autowired
    private TodoService todoService;

    @GetMapping
    public List getAllTodos() {
        return todoService.getAllTodos();
    }

    @PostMapping
    public ResponseEntity createTodo(@RequestBody Todo todo) {
        return ResponseEntity.ok(todoService.createTodo(todo));
    }
}

4. Deploying the Service to AWS

After developing the application, you prepare to deploy it to AWS. To deploy to AWS, you need an AWS account. After creating an account, log in to the AWS Management Console.

4.1 Using Elastic Beanstalk

AWS Elastic Beanstalk is a PaaS (Platform as a Service) that simplifies the deployment of web applications and services. You can deploy your application through the following steps:

Create Elastic Beanstalk Environment
Select Elastic Beanstalk in the AWS Management Console and click the “Create New Application” button. Enter the application name and description.
Configure Environment
When configuring the environment, select “Web server environment” and choose “Java” as the platform. Options will be provided to upload the JAR file.
Create Application JAR File
Build the project in IntelliJ IDEA to generate the JAR file. You can create it using the mvn clean package command.
Upload JAR File
Return to the Elastic Beanstalk dashboard and upload the generated JAR file. Then click the “Create Environment” button to create the environment.

4.2 Check Environment URL

Once the environment is created, you can access the application through the URL provided by AWS. Enter this URL in the browser to verify that the application is functioning correctly.

4.3 Integrating with the Database

In a production environment, it is common to manage the database using RDS (Amazon Relational Database Service). Let’s explain how to set up RDS and connect the application to the database:

Create RDS Instance
In the RDS dashboard, click “Create database”. Choose a database engine and complete the instance type and other settings.
Set Security Group
Set the security group for the RDS instance to allow access from the application.
Update Application Settings
Add the connection information for RDS to the application’s application.properties file:
```
spring.datasource.url=jdbc:mysql://:/
spring.datasource.username=
spring.datasource.password=
```

5. Conclusion

In this course, we have explored how to develop and deploy a simple backend application using Spring Boot and AWS Elastic Beanstalk. Spring Boot provides a lot of convenience to developers, and AWS makes it easy to deploy developed applications. It will greatly help in building various services in real-world applications. I encourage you to continue learning more features and apply them in real business scenarios.