Spring Boot Backend Development Course, What is a Library

Spring Boot is a powerful and flexible web application framework written in the Java programming language. It is particularly optimized for backend development, helping developers quickly and easily build RESTful APIs or web applications. In this course, we will explore Spring Boot and its related libraries in depth.

1. Introduction to Spring Boot

Spring Boot is an extension of the Spring Framework, providing a tool to create stand-alone applications with minimal configuration. The main features of Spring Boot are as follows:

  • Easy Configuration: It minimizes XML configuration files and transitions to Java-based configuration, enhancing code readability and maintainability.
  • Application Independence: It allows applications to run using an embedded web server (e.g., Tomcat) without requiring separate server installation.
  • Automatic Configuration: It automatically finds configurations suited to the environment, saving developers a lot of time.
  • Extensive Community: Spring is a globally popular framework with a strong community and documentation.

2. Core Components of Spring Boot

Spring Boot has various components, each performing specific functions, contributing together to build powerful backend applications. Here, we will introduce some key components.

2.1. Spring MVC

Spring MVC (Model-View-Controller) is a pattern for web controllers that handles requests and assembles models and views to generate responses. Spring Boot’s MVC is very useful for creating REST APIs.


@RestController
@RequestMapping("/api/hello")
public class HelloController {
    @GetMapping
    public String sayHello() {
        return "Hello, Spring Boot!";
    }
}

2.2. Spring Data JPA

Spring Data JPA is a library that makes data access easier. It is an implementation of JPA (Java Persistence API) that simplifies interactions with the database. Using this feature allows database operations to be performed without writing complex SQL queries.

2.3. Spring Security

Spring Security is a library for securing applications. It controls user access through Authentication and Authorization, helping build secure applications through basic security configurations.

3. What is a Library?

In programming, a library refers to a pre-written set of code that developers can reuse. Generally, it consists of code, modules, and functions that perform specific functions, allowing developers to refer to this library for efficient work. In the case of Spring Boot, rapid development is possible through various libraries.

3.1. Features of Libraries

  • Reusability: Code written once can be reused across multiple projects.
  • Increased Productivity: Existing libraries can be used without the need to implement complex features from scratch.
  • Ease of Maintenance: When a library is updated, the applications using it can also easily switch to the latest version.
  • Community Support: Open-source libraries typically have active communities that assist in problem-solving.

3.2. Key Libraries in Spring Boot

Spring Boot utilizes several libraries to provide various functionalities. Here, we introduce a few key libraries.

  • Spring Web: A library for web application development, including MVC and REST support features.
  • Spring Boot Starter Data JPA: A library that helps easily use JPA.
  • Spring Boot Starter Security: It includes essential libraries for security.
  • Spring Boot Starter Thymeleaf: It is used to create dynamic web pages using the server-side template engine Thymeleaf.

4. Using Spring Boot Libraries

Now, let’s learn how to use libraries in Spring Boot. In Spring Boot, libraries can be added using build tools like Maven or Gradle.

4.1. Adding Libraries with Maven

When using Maven, dependencies must be added to the pom.xml file. Below is an example of adding JPA and Web Starter:



    
        org.springframework.boot
        spring-boot-starter-data-jpa
    
    
        org.springframework.boot
        spring-boot-starter-web

4.2. Adding Libraries with Gradle

When using Gradle, dependencies are added to the build.gradle file:


dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
    implementation 'org.springframework.boot:spring-boot-starter-web'
}

5. Building a Spring Boot Backend Application

Let’s explore how to build a simple backend application using Spring Boot. As an example, we will create a RESTful API. The following outlines the basic process.

5.1. Environment Setup

First, create a new Spring Boot project in your IDE (e.g., IntelliJ IDEA). Select the basic dependencies for web and JPA.

5.2. Creating an Entity Class

Create an Entity class mapped to the database:


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

    private String name;
    private String email;

    // getters and setters
}

5.3. Writing a Repository Interface

Write a Repository interface that automatically provides CRUD functionalities through Spring Data JPA:


public interface UserRepository extends JpaRepository {
}

5.4. Writing a Service Class

Write a service class that performs business logic:


@Service
public class UserService {

    @Autowired
    private UserRepository userRepository;

    public List getAllUsers() {
        return userRepository.findAll();
    }

    public User createUser(User user) {
        return userRepository.save(user);
    }
}

5.5. Writing a Controller Class

Write a REST API controller that handles HTTP requests:


@RestController
@RequestMapping("/api/users")
public class UserController {

    @Autowired
    private UserService userService;

    @GetMapping
    public List getAllUsers() {
        return userService.getAllUsers();
    }

    @PostMapping
    public User createUser(@RequestBody User user) {
        return userService.createUser(user);
    }
}

6. Advantages of Spring Boot

There are several advantages to using Spring Boot. It contributes to increased development efficiency, improved maintainability, and overall enhanced code quality.

6.1. Rapid Development

Through automatic configuration and minimal setup, development can proceed quickly. You can choose to use only the necessary features, avoiding unnecessary code writing.

6.2. Community-Based Support

As Spring Boot is used by many developers worldwide, there are various resources and examples available to help resolve issues. Information can be easily found through blogs, forums, and official documentation.

7. Conclusion

In this course, we explored Spring Boot and its libraries in detail. Utilizing Spring Boot provides the advantage of easily building powerful backend systems. We hope you will continue to add various features using Spring Boot and develop more advanced applications.

Thank you!