In this course, you will learn how to create a blog using Spring Boot, and we will explore how to write test code that will reduce repetitive tasks. This blog project is one of the best ways to practically learn and will further enhance your skills as a developer. The course content is aimed at everyone from beginners to intermediate learners.
1. Introduction to Spring Boot
Spring Boot is a simplified configuration of the Spring Framework that helps you develop Spring applications quickly and easily. Using Spring Boot minimizes complex setups or XML configurations and offers the advantage of integrating various embedded servers.
1.1 Advantages of Spring Boot
- Quick Start: You can quickly run simple applications using pre-configured templates.
- Auto Configuration: Spring Boot automatically sets up the components of your application.
- Embedded Servers: You can run applications without separate server installations using embedded servers like Tomcat and Jetty.
- Dependency Management: Managing dependencies through Maven or Gradle is easy.
2. Project Environment Setup
Now let’s set up the environment to create the actual blog application. You can configure the project using the Spring Initializr.
2.1 Using Spring Initializr
- Go to Spring Initializr in your web browser.
- Enter the project metadata:
- Project: Maven Project
- Language: Java
- Spring Boot: Select the latest version
- Group: com.example
- Artifact: blog
- Name: blog
- Package name: com.example.blog
- Select the following in Dependencies:
- Spring Web
- Spring Data JPA
- H2 Database (can be switched to MySQL)
- Spring Boot DevTools
- Click the Generate button to download the ZIP file.
3. Blog Application Structure
After configuring the project, we will look at the application structure. A proper directory structure enhances maintainability and readability.
3.1 Directory Structure
blog
├── src
│ ├── main
│ │ ├── java
│ │ │ └── com
│ │ │ └── example
│ │ │ └── blog
│ │ │ ├── BlogApplication.java
│ │ │ ├── controller
│ │ │ ├── model
│ │ │ └── repository
│ │ └── resources
│ │ ├── application.properties
│ │ └── static
│ │ └── ...
└── test
4. Creating Basic Models and Repositories
Now, we will create the basic model classes and repository for the blog. The model represents a blog post, while the repository interacts with the database.
4.1 Creating the Model Class
First, we create the BlogPost model class.
package com.example.blog.model;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Column;
import java.time.LocalDateTime;
@Entity
public class BlogPost {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
@Column(nullable = false)
private String title;
@Column(nullable = false, length = 5000)
private String content;
private LocalDateTime createdAt;
public BlogPost() {
this.createdAt = LocalDateTime.now();
}
// Getters and Setters
}
4.2 Creating the Repository Interface
Next, we create the BlogPostRepository interface to utilize JPA’s CRUD functionalities.
package com.example.blog.repository;
import com.example.blog.model.BlogPost;
import org.springframework.data.jpa.repository.JpaRepository;
public interface BlogPostRepository extends JpaRepository {
}
5. Creating Controllers and Implementing REST API
We will create a REST API to manage the data of blog posts. To do this, we will write the controller class.
5.1 Creating the REST Controller
package com.example.blog.controller;
import com.example.blog.model.BlogPost;
import com.example.blog.repository.BlogPostRepository;
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 BlogPostController {
@Autowired
private BlogPostRepository blogPostRepository;
@GetMapping
public List getAllPosts() {
return blogPostRepository.findAll();
}
@PostMapping
public BlogPost createPost(@RequestBody BlogPost blogPost) {
return blogPostRepository.save(blogPost);
}
@GetMapping("/{id}")
public ResponseEntity getPostById(@PathVariable Long id) {
return blogPostRepository.findById(id)
.map(post -> ResponseEntity.ok().body(post))
.orElse(ResponseEntity.notFound().build());
}
// Additional Update and Delete methods
}
6. Writing Test Code
In this section, we will write test code to verify that the REST API we created works correctly. Spring Boot allows for easy testing using JUnit and Mockito.
6.1 Setting Up the Test Environment
org.springframework.boot
spring-boot-starter-test
test
6.2 Example of Testing the REST API
package com.example.blog;
import com.example.blog.model.BlogPost;
import com.example.blog.repository.BlogPostRepository;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.http.MediaType;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.result.MockMvcResultMatchers;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.*;
@SpringBootTest
@AutoConfigureMockMvc
public class BlogPostControllerTest {
@Autowired
private MockMvc mockMvc;
@Autowired
private BlogPostRepository blogPostRepository;
private ObjectMapper objectMapper;
@BeforeEach
public void setUp() {
objectMapper = new ObjectMapper();
blogPostRepository.deleteAll();
}
@Test
public void createPost_ShouldReturnCreatedPost() throws Exception {
BlogPost post = new BlogPost();
post.setTitle("Title");
post.setContent("Body content");
mockMvc.perform(post("/api/posts")
.content(objectMapper.writeValueAsString(post))
.contentType(MediaType.APPLICATION_JSON))
.andExpect(MockMvcResultMatchers.status().isCreated());
}
// Additional method tests
}
7. Running the Project
You are now ready to run the blog application. By running the BlogApplication.java file in your IDE, the embedded server will start, and you can use the REST API.
7.1 Testing the API with Postman
You can use API testing tools like Postman to test the REST API you created. Experience adding and retrieving blog posts through POST and GET requests.
Conclusion
In this Spring Boot backend development course, we learned the core features of Spring Boot by developing a simple blog application. We experienced interactions with the database through basic CRUD operations and learned ways to make the development process more efficient by writing test code.
Based on this project, feel free to add more features and improve the design to evolve into a more complete blog application. We hope you continue to take on new features and frameworks in the future. Thank you.