Spring Boot Backend Development Course, Blog Screen Composition Example, Adding Dependencies for Using Thymeleaf

Introduction

Spring Boot is a lightweight web application framework based on the Spring Framework, designed to help developers quickly build applications. In particular, Spring Boot offers many features in backend development, such as RESTful web services, database integration, and security management. In this tutorial, we will cover an example of configuring a blog screen using Spring Boot and learn about adding dependencies for Thymeleaf.

Blog Screen Configuration Example

1. Creating the Project

To create a Spring Boot project, we will use Spring Initializr. Please select the following settings.

  • Project: Gradle Project
  • Language: Java
  • Spring Boot: 2.7.0 (select the latest version)
  • Group: com.example
  • Artifact: blog
  • Name: blog
  • Description: Blog application
  • Package name: com.example.blog
  • Packaging: Jar
  • Java: 11

Next, add ‘Spring Web’, ‘Thymeleaf’, ‘Spring Data JPA’, and ‘H2 Database’ in the Dependencies section and generate the project.

2. Adding Dependencies

Once the Spring Boot project is created, let’s check the required dependencies in the build.gradle file. The dependencies should be added as shown below.

dependencies {
        implementation 'org.springframework.boot:spring-boot-starter-web'
        implementation 'org.springframework.boot:spring-boot-starter-thymeleaf'
        implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
        runtimeOnly 'com.h2database:h2'
    }

3. Designing the Blog Domain

Now, let’s design the domain model that will constitute the blog. A model representing blog posts is essential.

package com.example.blog.model;

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

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

    // getters and setters
}

4. Adding the Repository

Let’s add the repository interface. This will contain the logic to interact with the database.

package com.example.blog.repository;

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

public interface PostRepository extends JpaRepository {
}

5. Adding the Service Layer

We will now add a service layer to manage blog posts. This will include methods for creating and retrieving posts.

package com.example.blog.service;

import com.example.blog.model.Post;
import com.example.blog.repository.PostRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class PostService {
    @Autowired
    private PostRepository postRepository;

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

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

6. Adding the Controller

Now, let’s add a controller to handle requests for the web application.

package com.example.blog.controller;

import com.example.blog.model.Post;
import com.example.blog.service.PostService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;

import java.util.List;

@Controller
@RequestMapping("/posts")
public class PostController {
    @Autowired
    private PostService postService;

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

    @GetMapping("/new")
    public String newPostForm(Model model) {
        model.addAttribute("post", new Post());
        return "postForm";
    }

    @PostMapping
    public String savePost(Post post) {
        postService.savePost(post);
        return "redirect:/posts";
    }
}

7. Configuring Thymeleaf Templates

Now, let’s configure the blog screen using Thymeleaf. Create postList.html and postForm.html files in the src/main/resources/templates folder.

postList.html

<!DOCTYPE html>
    <html xmlns:th="http://www.w3.org/1999/xhtml">
        <head>
            <title>Blog Post List</title>
        </head>
        <body>
            <h1>Blog Post List</h1>
            <a href="@{/posts/new}">Create New Post</a>
            <ul>
                <li th:each="post : ${posts}">
                    <h2 th:text="${post.title}"></h2>
                    <p th:text="${post.content}"></p>
                </li>
            </ul>
        </body>
    </html>

postForm.html

<!DOCTYPE html>
    <html xmlns:th="http://www.w3.org/1999/xhtml">
        <head>
            <title>Create New Post</title>
        </head>
        <body>
            <h1>Create New Post</h1>
            <form th:action="@{/posts}" method="post">
                <label for="title">Title</label>
                <input type="text" id="title" name="title" required/>

                <label for="content">Content</label>
                <textarea id="content" name="content" required></textarea>

                <button type="submit">Save</button>
            </form>
        </body>
    </html>

Conclusion

In this tutorial, we learned how to create a simple blog application using Spring Boot. We implemented features for writing blog posts and retrieving the list of posts, as well as how to create HTML templates with Thymeleaf. Based on this tutorial, feel free to add more complex features to create your own blog.

Additional Resources

If you want to learn more, consider checking the following resources.

Spring Boot Backend Development Course, Blog Screen Layout Example, Writing Controllers for Learning Thymeleaf Syntax

1. Overview

This course helps to provide a basic understanding of backend development using Spring Boot and explains how to learn Thymeleaf syntax through a blog screen composition example.

Spring Boot is a Java-based web application framework that helps you create web applications quickly and easily without complex configurations. This allows developers to focus on business logic and increase productivity.

2. Tech Stack

The main tech stack used in this course includes:

  • Java 11 or higher
  • Spring Boot 2.x
  • Thymeleaf
  • Spring Data JPA
  • H2 Database

This tech stack forms a strong combination for backend development. A brief description of each tech stack is as follows.

  • Java: An object-oriented programming language that is platform-independent.
  • Spring Boot: A framework that simplifies configuration and deployment in Java Spring.
  • Thymeleaf: An HTML5 template engine used for composing views.
  • Spring Data JPA: A library that makes it easier to interact with the database.
  • H2 Database: A lightweight, in-memory database suitable for testing and prototyping.

3. Project Setup

To set up a Spring Boot project, use Spring Initializr. Access Spring Initializr and configure the following settings:

  • Project: Maven Project
  • Language: Java
  • Spring Boot: 2.x
  • Group: com.example
  • Artifact: blog
  • Dependencies: Spring Web, Thymeleaf, Spring Data JPA, H2 Database

Save the above settings and download the project. Then import it in your IDE to start working.

4. Create Entity Class

Create entity classes to define the data models needed for the application. To store basic blog posts, the Post entity class is created as follows:

package com.example.blog.model;

import javax.persistence.*;

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

    @Column(nullable = false)
    private String title;

    @Column(nullable = false)
    private String content;

    private String author;

    // getters and setters
}

This class contains the ID, title, content, and author of the post. It handles the mapping to the database using JPA.

5. Create Repository Interface

Create a repository interface that extends JpaRepository to handle CRUD operations for the Post entity:

package com.example.blog.repository;

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

public interface PostRepository extends JpaRepository {
}

This interface allows easy access to CRUD operations associated with the Post entity in the database.

6. Write Service Class

Create a service class that handles business logic and defines business rules. The PostService class is written as follows:

package com.example.blog.service;

import com.example.blog.model.Post;
import com.example.blog.repository.PostRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class PostService {
    private final PostRepository postRepository;

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

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

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

    public Post findById(Long id) {
        return postRepository.findById(id).orElse(null);
    }

    public void deleteById(Long id) {
        postRepository.deleteById(id);
    }
}

This class defines methods to retrieve the list of posts, save posts, and delete posts.

7. Write Controller

Now, let’s write the controller class to handle client requests. The PostController class can be written as follows:

package com.example.blog.controller;

import com.example.blog.model.Post;
import com.example.blog.service.PostService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.*;

import java.util.List;

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

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

    @GetMapping
    public String list(Model model) {
        List posts = postService.findAll();
        model.addAttribute("posts", posts);
        return "post/list";
    }

    @GetMapping("/new")
    public String createForm(Model model) {
        model.addAttribute("post", new Post());
        return "post/form";
    }

    @PostMapping
    public String create(Post post) {
        postService.save(post);
        return "redirect:/posts";
    }
    
    @GetMapping("/{id}")
    public String view(@PathVariable Long id, Model model) {
        Post post = postService.findById(id);
        model.addAttribute("post", post);
        return "post/view";
    }

    @GetMapping("/edit/{id}")
    public String editForm(@PathVariable Long id, Model model) {
        Post post = postService.findById(id);
        model.addAttribute("post", post);
        return "post/form";
    }

    @PostMapping("/edit/{id}")
    public String edit(@PathVariable Long id, Post post) {
        post.setId(id);
        postService.save(post);
        return "redirect:/posts";
    }

    @GetMapping("/delete/{id}")
    public String delete(@PathVariable Long id) {
        postService.deleteById(id);
        return "redirect:/posts";
    }
}

The controller defines handler methods for HTTP requests following the pattern. The above code implements listing, creating, editing, and deleting posts functionalities.

8. Write Thymeleaf Template

Now it’s time to create the HTML view using Thymeleaf. The list.html to display the list of posts can be written as follows:

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
    <title>Post List</title>
</head>
<body>
    <h1>Post List</h1>
    <a href="@{/posts/new}">Create New Post</a>
    <ul>
        <li th:each="post : ${posts}">
            <a th:href="@{/posts/{id}(id=${post.id})}">[[${post.title}]]</a>
        </li>
    </ul>
</body>
</html>

The above template displays the list of posts, where clicking on each post title will take you to the details page of that post.

9. Conclusion

This course introduced how to build a simple blog application using Spring Boot and Thymeleaf. I hope it helped you understand basic backend development by creating entity, repository, service, controller, and view step by step.

If you want to add more features, consider implementing comment functionality for posts, user authentication, and permission management. This will help you build a solid foundation for more advanced web application development.

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.

Spring Boot Backend Development Course, Blog Screen Layout Example, Adding Creation and Modification Time to the Entity

Blog Screen Composition Example

Developing a blog web application using Spring Boot is a very useful skill in modern web development. In this tutorial, we will cover how to create a simple blog screen using Spring Boot and also learn how to add creation and modification timestamps to the entity.

1. What is Spring Boot?

Spring Boot is an open-source framework that helps you use the Java-based Spring framework more easily. Its main feature is minimizing initial setup and configuration so that developers can focus on business logic. In this tutorial, we will implement various features while creating a blog application using Spring Boot.

2. Project Setup

To set up a Spring Boot project, we use Spring Initializr. You can create a project with the following settings.

  • Project: Maven Project
  • Language: Java
  • Spring Boot: 2.5.x or the latest version
  • Group: com.example
  • Artifact: blog
  • Dependencies: Spring Web, Spring Data JPA, H2 Database, Lombok

Open the created project in your IDE and start working.

3. Blog Entity Structure

The core of the blog application is the Post entity. This entity represents a blog post and usually includes a title, content, creation time, and modification time.

package com.example.blog.entity;

import lombok.Getter;
import lombok.Setter;

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

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

    private String title;

    @Column(length = 10000)
    private String content;

    private LocalDateTime createdAt;

    private LocalDateTime updatedAt;

    @PrePersist
    public void onCreate() {
        this.createdAt = LocalDateTime.now();
    }

    @PreUpdate
    public void onUpdate() {
        this.updatedAt = LocalDateTime.now();
    }
}

The code above shows the structure of the Post entity. The @Entity annotation indicates that this class is a JPA entity, and @Id and @GeneratedValue are used to generate the primary key. Creation and modification times are automatically managed using LocalDateTime.

4. Database Configuration

In this example, we will use the H2 database. Add the following to the application.properties file to configure the H2 database.

spring.h2.console.enabled=true
spring.datasource.url=jdbc:h2:mem:testdb
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=password
spring.jpa.hibernate.ddl-auto=create

Enabling the H2 console allows you to directly access the database through a browser.

5. Create Repository Interface

We create a repository for interactions with the database. By using Spring Data JPA, basic CRUD functionality is provided just by defining the interface.

package com.example.blog.repository;

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

public interface PostRepository extends JpaRepository {
}

6. Implement Service Layer

The service layer is where business logic is handled. We will create a PostService class to implement CRUD functionality for blog posts.

package com.example.blog.service;

import com.example.blog.entity.Post;
import com.example.blog.repository.PostRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class PostService {

    @Autowired
    private PostRepository postRepository;

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

    public Post findById(Long id) {
        return postRepository.findById(id).orElse(null);
    }

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

    public void delete(Long id) {
        postRepository.deleteById(id);
    }
}

7. Implement Controller

Now we will create a PostController to handle user requests. This controller defines REST APIs and manages interactions with clients.

package com.example.blog.controller;

import com.example.blog.entity.Post;
import com.example.blog.service.PostService;
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/posts")
public class PostController {

    @Autowired
    private PostService postService;

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

    @GetMapping("/{id}")
    public ResponseEntity getPostById(@PathVariable Long id) {
        Post post = postService.findById(id);
        return post != null ? ResponseEntity.ok(post) : ResponseEntity.notFound().build();
    }

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

    @PutMapping("/{id}")
    public ResponseEntity updatePost(@PathVariable Long id, @RequestBody Post post) {
        post.setId(id);
        Post updatedPost = postService.save(post);
        return ResponseEntity.ok(updatedPost);
    }

    @DeleteMapping("/{id}")
    public ResponseEntity deletePost(@PathVariable Long id) {
        postService.delete(id);
        return ResponseEntity.noContent().build();
    }
}

8. Run Spring Boot Application

Once all configurations are completed, you can run the application by executing the BlogApplication class.

package com.example.blog;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class BlogApplication {

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

9. Summary of Overall Flow

All of the above processes are steps to implement a RESTful API for creating, modifying, and deleting posts. The frontend can be designed using modern frameworks like React or Vue.js, while the backend interacts with data through the above APIs.

10. Other Considerations

When developing a blog application, various features need to be considered. For example, user authentication and authorization, comment functionality, and a tagging system. These features can be implemented through additional entities and service classes.

In Conclusion

Developing a blog application using Spring Boot will be a very rewarding experience. It will enhance your understanding of the Spring framework, JPA, and RESTful APIs. I hope you can expand and develop your projects based on what we covered in this tutorial.

Appendix: References

Spring Boot Backend Development Course, Blog Screen Layout Example, Running Test

Blog Screen Composition Example and Running Test

1. What is Spring Boot?

Spring Boot is a framework for developing Java-based web applications built on the Spring Framework.
Many developers struggle with the complexity of the Spring Framework, and Spring Boot is designed to alleviate this.
Spring Boot minimizes configuration and helps users easily add the desired features.
The main purpose of Spring Boot is to enable a fast development and deployment process and provide a consistent experience across various projects.

2. Main Features of Spring Boot

  • Auto-configuration: Automatically handles many configurations, allowing developers to focus only on what is necessary.
  • Standalone: Runs with an embedded server (e.g., Tomcat, Jetty) without the need to deploy on an external web server.
  • Dependency Management: Easily manage required libraries through Maven or Gradle.
  • Integration with the Spring Ecosystem: Easy integration with various modules such as Spring Data, Spring Security, etc.

3. Setting Up the Spring Boot Development Environment

To develop with Spring Boot, you need to set up the following environment:

  1. Java Development Kit (JDK) installation: Install JDK version 1.8 or higher.
  2. Choose an IDE: Select an IDE such as IntelliJ IDEA, Eclipse, or VSCode.
  3. Choose a Build Tool: Select either Maven or Gradle to manage the project.

Here’s how to create a Spring Boot project in IntelliJ:

  1. Run IntelliJ IDEA and select “New Project”.
  2. Select Spring Initializr and enter the required settings (project metadata, etc.).
  3. Add necessary dependencies (e.g., Spring Web, Spring Data JPA, etc.).
  4. Once the project is created, it will open in the IDE.

4. Blog Screen Composition Example

In this tutorial, we will aim to build a basic blog application.
We will implement features to create and view posts.

4.1 Database Design

The blog application requires a database table to store posts.
Let’s design it with a simple structure as follows.


        CREATE TABLE posts (
            id BIGINT AUTO_INCREMENT PRIMARY KEY,
            title VARCHAR(255) NOT NULL,
            content TEXT NOT NULL,
            created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
        );
        

4.2 Creating an Entity Class

We will create an entity class corresponding to the posts using JPA.


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

        @Entity
        @Table(name = "posts")
        public class Post {
            @Id
            @GeneratedValue(strategy = GenerationType.IDENTITY)
            private Long id;
            private String title;
            @Column(columnDefinition = "TEXT")
            private String content;
            private LocalDateTime createdAt = LocalDateTime.now();

            // Getters and Setters
        }
        

4.3 Creating a Repository Interface

We will manipulate the database using the JPA repository.


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

        public interface PostRepository extends JpaRepository {
        }
        

4.4 Creating a Service Class

We will create a service class to handle business logic.


        import org.springframework.beans.factory.annotation.Autowired;
        import org.springframework.stereotype.Service;
        import java.util.List;

        @Service
        public class PostService {
            @Autowired
            private PostRepository postRepository;

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

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

4.5 Creating a REST Controller

We will write a RESTful controller to handle HTTP requests.


        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 PostService postService;

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

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

4.6 Setting Application Properties

Modify the application.properties file to set up database connection information.


        spring.datasource.url=jdbc:mysql://localhost:3306/your_db_name
        spring.datasource.username=your_username
        spring.datasource.password=your_password
        spring.jpa.hibernate.ddl-auto=update
        

5. Running Tests

Run the application to test the API.
You can use tools like Postman to call the REST API.

5.1 Testing GET Request

Send a GET request to retrieve all posts,
and if a JSON-formatted response is returned, it is successful.

5.2 Testing POST Request

Try saving data to the database through a POST request to create a new post.
The request body must include the title and content.

5.3 Exception Handling and Response Format

Furthermore, you can improve the code to implement appropriate error handling and
return appropriate HTTP response status codes.

In this tutorial, we looked at how to build a simple blog application using Spring Boot.
Based on this basic example, I hope you can add and expand your own blog features.