1. Introduction

Spring Boot is a Java-based web framework that helps developers quickly build applications. In this course, we will cover how to develop the backend of a blog application using Spring Boot and create HTML views for testing.

We will learn how to design RESTful APIs, manage data exchange with clients, and provide visual content to users through HTML views. Through this, we will gain an overall understanding of Spring Boot and the structure of web applications.

2. Setting Up the Development Environment

The process of setting up a development environment using Spring Boot is as follows:

1. Install JDK: Spring Boot is implemented in Java, so you must install the Java Development Kit (JDK). JDK 11 or higher is recommended.
2. Set up an IDE: Install an Integrated Development Environment (IDE) such as IntelliJ IDEA or Eclipse.
3. Create a Spring Boot Project: Use Spring Initializr to create a new Spring Boot project.

3. Creating a Spring Boot Project

Here’s how to create a project using Spring Initializr:

1. Go to Spring Initializr.
2. Project: Choose (Maven Project or Gradle Project)
3. Language: Java
4. Spring Boot: Select the latest version
5. Fill in Project Metadata: Group, Artifact, Name, Description, etc.
6. Select Spring Web, Thymeleaf in Dependencies
7. Click the Generate button to download the project
8. Open the downloaded zip file in your IDE

4. Adding Dependencies

To manage the dependencies required for the application you are developing, you will need to modify the build.gradle or pom.xml file. Generally, libraries such as Spring, JPA, and Thymeleaf are added.

5. Designing the RESTful API

Design the RESTful API for the blog application. The goal is to design an API that provides basic CRUD (Create, Read, Update, Delete) functionalities.

5.1. Defining the Domain Model

To manage the blog posts, we define a Post entity:

@Entity
public class Post {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    private String title;
    private String content;
    private LocalDateTime createdAt;

    // Getter and Setter
}

5.2. Creating the Repository Interface

Create a repository for interacting with the database through Spring Data JPA:

@Repository
public interface PostRepository extends JpaRepository {
    List findAll();
}

5.3. Creating the Service Class

Implement a service class to handle business logic:

@Service
public class PostService {
    private final PostRepository postRepository;

    public PostService(PostRepository postRepository) {
        this.postRepository = postRepository;
    }

    public List getAllPosts() {
        return postRepository.findAll();
    }

    public Post createPost(Post post) {
        return postRepository.save(post);
    }
}

5.4. Creating the Controller Class

Implement a controller class to handle HTTP requests:

@RestController
@RequestMapping("/api/posts")
public class PostController {
    private final PostService postService;

    public PostController(PostService postService) {
        this.postService = postService;
    }

    @GetMapping
    public List getAllPosts() {
        return postService.getAllPosts();
    }

    @PostMapping
    public Post createPost(@RequestBody Post post) {
        return postService.createPost(post);
    }
}

6. Creating HTML View

Let’s look at how to create an HTML view using Thymeleaf in Spring Boot.

6.1. Creating HTML Template

Create an HTML file in the src/main/resources/templates folder. For example, create home.html:

    


    
Blog Post List
    

        

        

    

6.2. Adding Method to Return HTML View in Controller

Add a method in the controller to return the HTML view:

@GetMapping("/home")
public String getHomePage(Model model) {
    List posts = postService.getAllPosts();
    model.addAttribute("posts", posts);
    return "home";
}

7. Testing and Running

Run the application and check the HTTP requests in a web browser to ensure the features are functioning correctly.

1. Run the application in the IDE to start the Spring Boot application.
2. Access http://localhost:8080/home in the browser to check the HTML view.
3. Test the RESTful API using Postman.

8. Conclusion

In this course, we learned how to develop the backend of a blog application using Spring Boot. We gained basic usage of Spring Boot through designing RESTful APIs, creating HTML views, and testing them.

Now you can develop your own various web applications based on Spring Boot. You will be able to implement more complex applications by leveraging the various features of Spring Boot.