Spring Boot Backend Development Course, Blog Screen Composition Example, Writing Controller Methods

1. Introduction

Spring Boot is a framework for Java development that helps developers quickly create applications with minimal configuration. This tutorial provides a detailed explanation of how to develop the backend of a blog application using Spring Boot. The goal of this article is to structure the basic screen of the blog and to write controller methods for it.

2. Setting Up the Development Environment

There are a few essential requirements for developing a Spring Boot application.

• Java Development Kit (JDK) 11 or higher
• IDE (e.g., IntelliJ IDEA, Eclipse)
• Gradle or Maven (build tools)
• Spring Boot CLI (optional)

Please prepare the above items. Now let’s create a simple blog project using Spring Boot.

3. Creating a Spring Boot Project

A Spring Boot project can be easily created through Spring Initializr (https://start.spring.io/). Add the necessary dependencies as follows:

• Spring Web
• Spring Data JPA
• H2 Database

After creating the project, open it in the IDE to check the basic structure.

4. Creating Domain Models and Repository

To structure the blog, we must first define the domain model. A typical blog includes Posts and Comments.

4.1 Creating Post Entity

package com.example.blog.model;

import javax.persistence.*;
import java.time.LocalDateTime;

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

    private String title;

    @Column(columnDefinition = "TEXT")
    private String content;

    private LocalDateTime createdAt;

    // Getters and Setters
}
    

The above code defines the Post entity. It includes a title, content, and creation date. Next, we will create a repository for this entity.

4.2 Creating Post Repository

package com.example.blog.repository;

import com.example.blog.model.Post;
import org.springframework.data.jpa.repository.JpaRepository;

public interface PostRepository extends JpaRepository {
}
    

5. Creating Controller and Writing Methods

Now we are ready to create a controller to handle HTTP requests. Let’s write a controller that provides basic CRUD functionality for the blog.

5.1 Creating PostController

package com.example.blog.controller;

import com.example.blog.model.Post;
import com.example.blog.repository.PostRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
@RequestMapping("/api/posts")
public class PostController {
    
    @Autowired
    private PostRepository postRepository;

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

    @GetMapping("/{id}")
    public Post getPost(@PathVariable Long id) {
        return postRepository.findById(id).orElse(null);
    }

    @PostMapping
    public Post createPost(@RequestBody Post post) {
        post.setCreatedAt(LocalDateTime.now());
        return postRepository.save(post);
    }

    @PutMapping("/{id}")
    public Post updatePost(@PathVariable Long id, @RequestBody Post postDetails) {
        Post post = postRepository.findById(id).orElse(null);
        if(post != null) {
            post.setTitle(postDetails.getTitle());
            post.setContent(postDetails.getContent());
            return postRepository.save(post);
        }
        return null;
    }

    @DeleteMapping("/{id}")
    public void deletePost(@PathVariable Long id) {
        postRepository.deleteById(id);
    }
}
    

In the above code, we defined various methods that perform CRUD (Create, Read, Update, Delete) functions.
Each method is responsible for retrieving the list of posts, fetching a specific post, creating a new post,
updating a post, or deleting a post.

6. Running the Application

Once all configurations are complete, you are ready to run the application. Click the run button in your IDE to execute the application.
The embedded Tomcat server will run by default, and by accessing http://localhost:8080/api/posts using a web browser,
you can check the list of posts through the methods you just wrote.

7. Conclusion

In this tutorial, we explained the basic backend structure of a blog application using Spring Boot.
We hope this has helped you lay the foundation for backend development, and may you progress further through continuous learning.
Thank you.