Spring Boot MVC Web application using Spring Data JPA and H2 Database

In this tutorial, we will learn how to build a Spring Boot MVC web application using Spring MVC and Spring Data JPA. 

We will be using the H2 in-memory database for storing the data.

Tools and Technologies Used

- Java 17+

- Spring boot 3+

- Spring framework 6+

- Spring Data JPA 

- H2 Database

- Eclipse STS

Development Process

1. Create a Spring Boot Project
2. Create JPA Entity
3. Configure Database
4. Create JPA Repository
5. Create Spring MVC Controller
6. Create a Thymeleaf template
7. Run the Spring boot project
8. Demo

1. Create a Spring Boot Project

Use the below guide to create a Spring boot project in Eclipse STS IDE:
-> Create Spring Boot Project in Spring Tool Suite [STS]

Make sure that you have added below Maven dependencies:
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <dependency>
      <groupId>com.h2database</groupId>
      <artifactId>h2</artifactId>
      <scope>runtime</scope>
    </dependency>

Create project structure as per the below screenshot:

2. Create JPA Entity

Let's create a User entity under the domain package and add the following content to it:
import jakarta.persistence.*;

@Entity
@Table(name = "users")
public class User {
	
	@Id
	@GeneratedValue(strategy = GenerationType.AUTO)
	private Integer id;
	
	@Column(name = "name")
	private String name;

	public User() {
	}

	public User(Integer id, String name) {
		this.id = id;
		this.name = name;
	}

	public Integer getId() {
		return id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

}

3. Configure Database

Spring boot automatically configures database details for the H2 in-memory database so we do not need to explicitly add the database configuration in the application.properties file.

Let's add the following properties to the application.properties file:
logging.level.org.springframework=INFO

################### Hibernate Configuration ##########################
spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true

SQL Script - Sample Data

Create a data.sql file under /resources folder and add the following content to it:
delete from users;

insert into users(id, name) values(1,'Admin');
insert into users(id, name) values(2,'Ram');
insert into users(id, name) values(3,'Krishna');

4. Create JPA Repository

Let's create a UserRepository for the User entity which gives CRUD database operations for the User:
import org.springframework.data.jpa.repository.JpaRepository;

public interface UserRepository extends JpaRepository<User, Integer>
{

}

5. Create Spring MVC Controller

Let's create UserController to handle HTTP GET requests and return a simple view ( Thymeleaf):
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 net.sourcecodeexamples.springboot.repositories.UserRepository;

/**
 * @author https://www.sourcecodeexamples.net/
 * HomeController handles HTTP Get request
 *
 */
@Controller
public class HomeController
{
	@Autowired UserRepository userRepository;
	
	@GetMapping("/")
	public String home(Model model)
	{
		model.addAttribute("users", userRepository.findAll());
		return "index";
	}
}

6. Create a Thymeleaf template

Let's create an index.html file under the /resources/templates folder and add the following content to it:
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" 
	  xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="utf-8"/>
<title>Spring Boot Web App using Spring MVC and Spring Data JPA</title>
</head>
<body>
	<h1>Spring Boot Web App using Spring MVC and Spring Data JPA</h1>
	<hr />
	<table>
		<thead>
			<tr>
				<th>Id</th>
				<th>Name</th>
			</tr>
		</thead>
		<tbody>
			<tr th:each="user : ${users}">
				<td th:text="${user.id}">Id</td>
				<td th:text="${user.name}">Name</td>
			</tr>
		</tbody>
	</table>
</body>
</html>

7. Run the Spring boot project

This is Spring Boot's main entity class.  From your IDE, run the Application.main() method as a standalone Java class that will start the embedded Tomcat server on port 8080 and point the browser to http://localhost:8080/.
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

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

Or use the below command to run the Spring boot app:
$ mvn spring-boot:run

8. Demo

Hit this URL in a browser: http://localhost:8080/

Conclusion

In conclusion, this tutorial provided a comprehensive guide on building a Spring Boot MVC web application using Spring MVC and Spring Data JPA. We explored the key concepts and components of a Spring Boot web application, including controllers, views, and data access objects. By leveraging Spring MVC, we were able to handle HTTP requests and map them to appropriate controller methods. Additionally, Spring Data JPA facilitated seamless integration with the database, enabling efficient data persistence and retrieval. Armed with the knowledge gained from this tutorial, you are now equipped to embark on your journey of developing robust and scalable web applications using the Spring Boot framework. So go ahead and start building amazing web applications with Spring Boot!


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