Spring Boot Backend Development Course, Blog Screen Configuration Example, Understanding Template Engine

In recent years, the importance of Rapid Application Development has grown, positioning Spring Boot as a powerful framework for efficiently creating Java-based web applications. In this course, we will explore how to develop a backend using Spring Boot, provide examples of blog screen composition, and delve into the concept of template engines.

1. What is Spring Boot?

Spring Boot is built on the Spring framework to simplify the settings and deployment of applications. Developers can quickly start applications without complex XML configurations or numerous library settings. A significant advantage is that it uses an embedded server, allowing the creation of standalone applications as JAR files without the need to create WAR files.

1.1 Key Features of Spring Boot

  • Auto-configuration: Spring Boot automatically configures the necessary settings, helping developers to work more conveniently.
  • Optional Dependency Management: Dependencies can be easily added, and they can be managed effortlessly using Maven or Gradle.
  • Command-based development: Using Spring Boot Starter, projects can be easily created from the command line interface (CLI).

2. Setting Up the Spring Boot Environment

The first step to starting with Spring Boot is setting up the development environment. We will install Spring Boot and implement basic settings through the following steps.

2.1 JDK Installation

To use Spring Boot, you need the Java Development Kit (JDK). Download and install the JDK from the official Oracle website.

2.2 IntelliJ IDEA Installation

For Spring Boot development, you need a convenient development tool like IntelliJ IDEA or Eclipse. Download and install the IDE of your choice.

2.3 Creating a New Project

1. Open IntelliJ IDEA and select 'New Project'
2. Choose Spring Initializr
3. Enter project metadata (group, artifact, name, etc.)
4. Select necessary dependencies (Spring Web, Spring Data JPA, etc.)
5. Complete project creation

3. Designing RESTful API

The biggest advantage of backend development using Spring Boot is the ease of implementing RESTful APIs. You can design APIs that follow the REST (Representational State Transfer) architectural style to efficiently handle communication with clients.

3.1 Creating a Basic Structure

Now, let’s create a simple RESTful API. First, create a controller class.

@RestController
@RequestMapping("/api/v1/blogs")
public class BlogController {
    private final BlogService blogService;

    public BlogController(BlogService blogService) {
        this.blogService = blogService;
    }

    @GetMapping
    public List getAllBlogs() {
        return blogService.getAllBlogs();
    }

    @PostMapping
    public Blog createBlog(@RequestBody Blog blog) {
        return blogService.createBlog(blog);
    }
}

3.2 Creating the Blog Service Class

The service class handles the business logic.

@Service
public class BlogService {
    @Autowired
    private BlogRepository blogRepository;

    public List getAllBlogs() {
        return blogRepository.findAll();
    }

    public Blog createBlog(Blog blog) {
        return blogRepository.save(blog);
    }
}

4. Database Setup

Now, you can connect to a database to store and manage blog data. Using Spring Data JPA makes it easy to interact with the database.

4.1 Adding Dependencies

Add H2 database and Spring Data JPA dependencies to the pom.xml file.

<dependency>
    <groupId>com.h2database</groupId>
    <artifactId>h2</artifactId>
    <scope>runtime</scope>
</dependency>

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>

4.2 Creating the Entity Class

Create an entity class that represents the blog data.

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

    private String title;
    private String content;
    private String author;

    // Getters and Setters
}

5. Blog Screen Composition

Now that we have completed the backend for the blog, let’s prepare the screen composition for connecting it with the frontend. The frontend should be ready to display data through REST API calls.

5.1 HTML Template

Using the principles of blending, create the HTML structure for the blog. With a template engine like Thymeleaf, you can dynamically display data.

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>My Blog</title>
</head>
<body>
    <h1>Blog Posts</h1>
    <div th:each="blog : ${blogs}">
        <h2 th:text="${blog.title}"></h2>
        <p th:text="${blog.content}"></p>
        <p>Author: <span th:text="${blog.author}"></span></p>
    </div>
    <form action="/api/v1/blogs" method="post">
        <input type="text" name="title" placeholder="Title" required><br>
        <textarea name="content" placeholder="Content" required></textarea><br>
        <input type="text" name="author" placeholder="Author" required><br>
        <button type="submit">Add Post</button>
    </form>
</body>
</html>

5.2 Thymeleaf Template Engine

Thymeleaf is a frequently used template engine with Spring Boot. It can generate HTML on the server side and combine it with dynamic data to return to the client.

6. Concept of Template Engines

A template engine is a tool for dynamically generating HTML content in web applications. Developers can insert data into a predefined HTML structure to create the final content shown to users.

6.1 Types of Template Engines

  • Thymeleaf: The most widely used template engine in Spring-based applications. It is easy to use due to its compatibility with HTML5.
  • Freemarker: Provides powerful features for template files and can output in various formats, including XML.
  • Mustache: Minimizes logic and offers a simple and intuitive syntax.

6.2 How Template Engines Work

Template engines work by using HTML template files requested by the client, combining them with data on the server, and then returning the final generated HTML file to the client. This process works in a server-side rendering mode, making it easy for SEO optimization.

Conclusion

In this course, we have learned the basics of backend development using Spring Boot. We hope this has motivated you to build actual applications through blog screen composition examples and the concept of template engines. We encourage you to implement more complex systems and diverse features with Spring Boot. In the next course, we will cover more in-depth topics.