Building Web Applications with Spring MVC

Tutorial 3 of 5

1. Introduction

In this tutorial, we will delve into the world of web application development with Spring MVC. Our goal is to create a simple web application from scratch using Spring MVC.

Spring MVC, part of the larger Spring Framework, follows the Model-View-Controller design pattern. This pattern makes it easy to separate concerns within your application and makes it easier to maintain and test your code.

By the end of this tutorial, you will understand the basics of Spring MVC, how to set up a Spring MVC project, and how to handle user requests.

Prerequisites

Basic knowledge of Java
Basic understanding of web development concepts
An IDE such as IntelliJ IDEA or Eclipse
Maven installed on your system

2. Step-by-Step Guide

Spring MVC separates an application into three layers: Model, View, and Controller.

Model: This is the data layer of your application. It holds your data and the logic to manipulate that data.
View: This is the presentation layer of your application. It's responsible for displaying the data to the user.
Controller: This acts as an intermediary between the Model and View. It handles user requests and updates the Model, which in turn updates the View.

To create a Spring MVC application, we need to:

Set up a Spring project: This involves creating a new Maven project, adding necessary dependencies, and creating a project structure.
Create a Controller: The Controller handles user requests and returns a model to the View.
Create a View: The View presents the model data to the user.
Configure Spring MVC: This involves setting up a DispatcherServlet and a Spring configuration file.

3. Code Examples

Let's create a simple "Hello, World!" application.

1. Set up a Spring MVC project

Create a new Maven project and add the following dependencies to your pom.xml:

<dependencies>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>5.3.10</version>
    </dependency>
</dependencies>

2. Create a Controller

Create a new Java class called HelloController.java in your project:

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class HelloController {
    @RequestMapping("/hello")
    public String sayHello(Model model) {
        model.addAttribute("greeting", "Hello, World!");
        return "hello";
    }
}

This controller listens for requests at /hello and adds a greeting message to the model.

3. Create a View

Create a new HTML file hello.html in your project:

<!DOCTYPE html>
<html>
<body>
    <h1 th:text="${greeting}"></h1>
</body>
</html>

This view displays the greeting message from the model.

4. Configure Spring MVC

Create a new Java class called WebConfig.java in your project:

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
@EnableWebMvc
public class WebConfig implements WebMvcConfigurer {
}

This configuration class enables Spring MVC.

4. Summary

In this tutorial, we've covered the basics of Spring MVC. We've set up a Spring MVC project, created a controller and a view, and configured Spring MVC.

Next steps for you could be exploring how to handle form submissions, validating user input, and understanding how to connect to a database with Spring MVC.

Check out the official Spring MVC documentation for more detailed information.

5. Practice Exercises

Exercise 1: Create a Spring MVC application that displays a list of books.

Exercise 2: Extend the above application to allow adding new books.

Exercise 3: Extend the application to allow editing and deleting books.

For each exercise, you should create a controller, a model, and views. Experiment with different types of data and different ways of interacting with that data.

Remember, the best way to learn is by doing. Good luck!