Understanding MVC Architecture & Spring Boot Flow for Beginners

Matin May 04, 2025

If you're starting your journey into web development using Spring Boot, you'll often hear the term MVC Architecture. But what is it? And how does a typical Spring Boot application work behind the scenes?

Let’s break it down in simple terms.

🚀 What is MVC?

MVC stands for Model-View-Controller. It's a design pattern that separates your code into three main parts:

1. Model

  • Represents data and business logic.
  • Interacts with the database.
  • Example: A User class representing a table in your database.

    2. View

    • Responsible for the UI (User Interface).
    • Usually HTML pages, or front-end frameworks.
    • Displays data to the user.

      3. Controller

      • Acts like a traffic cop.
      • Receives requests, processes them (with help from the Model), and returns the appropriate View.
      • Example: When a user clicks "Login", the controller handles that request.

        🧩 How It Works – The MVC Flow

        Let’s imagine you are visiting a page to view your profile:

        Here’s what happens step-by-step:

        1. User Request: You type a URL like http://localhost:8080/profile.
        2. Controller: The controller catches this request using a method with @GetMapping("/profile").
        3. Model: The controller asks the service or repository layer to fetch user data.
        4. Service/Repository: Talks to the database and gets the data (using JPA or JDBC).
        5. View: Controller returns this data to the HTML template (e.g., using Thymeleaf).
        6. Response: The final rendered page is shown in your browser.

          🛠️ Spring Boot MVC in Action (Code Example)

          Let’s create a simple MVC flow where we fetch and display users.

          1. Model (User.java) 

          @Entity
public class User {
    @Id
    private Long id;
    private String name;
    private String email;
    // getters and setters
}


          2. Repository (UserRepository.java) 

          public interface UserRepository extends JpaRepository<User, Long> {}


          3. Service (UserService.java) 

          @Service
public class UserService {
    @Autowired
    private UserRepository userRepo;

    public List<User> getAllUsers() {
        return userRepo.findAll();
    }
}


          4. Controller (UserController.java) 

          @Controller
public class UserController {
    @Autowired
    private UserService userService;

    @GetMapping("/users")
    public String showUsers(Model model) {
        model.addAttribute("users", userService.getAllUsers());
        return "user-list"; // returns user-list.html
    }
}


          5. View (user-list.html) 

          <!DOCTYPE html>
<html>
<head><title>User List</title></head>
<body>
<h1>All Users</h1>
<ul>
    <th:block th:each="user : ${users}">
        <li th:text="${user.name}"></li>
    </th:block>
</ul>
</body>
</html>


          🔁 Summary of Spring Boot Flow

          1. Controller handles HTTP requests.
          2. It talks to the Service, which uses a Repository to fetch data from the database.
          3. The data is passed back to the View (HTML).
          4. The final page is sent to the user’s browser.

            📌 Why Use MVC in Spring Boot?

            ✅ Clean separation of concerns
            ✅ Easier to manage, test, and scale
            ✅ Reusable components
            ✅ Popular and industry-standard

            🎯 Final Thoughts

            Spring Boot + MVC makes your web application development fast, structured, and beginner-friendly. Once you understand this flow, you'll be able to build registration forms, dashboards, blogs, or even full eCommerce sites with ease.

            Matin

            Posted by Matin

            I'm an aspiring full-stack web developer with a relentless passion for crafting scalable web applications.

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