30.3. Developing REST APIs with Spring Boot: Creating a new Spring Boot project

30.3. Developing REST APIs with Spring Boot: Creating a New Spring Boot Project

Spring Boot is a Spring Framework project that aims to simplify the process of configuring and publishing Spring-based applications. It allows developers to create stand-alone applications that can be run using 'java -jar' or more traditionally in a servlet container. One of the main uses of Spring Boot is to create RESTful APIs quickly and efficiently.

Starting a Spring Boot Project

To start a Spring Boot project, the easiest way is to use Spring Initializr, an online tool that generates the project's base structure. Go to start.spring.io and fill in the necessary information for your project, such as project type (Maven or Gradle), language ( Java, Kotlin or Groovy), Spring Boot version, initial dependencies and project metadata (artifact name, group, etc.).

For developing a REST API, some common dependencies you may want to add are:

• Spring Web: to create web applications, including RESTful, using Spring MVC. It provides features such as mapping HTTP requests to controller methods and serializing objects to JSON/XML.
• Spring Data JPA: for data persistence in SQL with Java Persistence API.
• Spring Security: to add security to your application, such as authentication and authorization.
• H2 Database: an in-memory database to facilitate development and testing.
• Lombok: a Java library that helps reduce boilerplate code.

After selecting the desired dependencies, click "Generate" to download the ZIP file with the project. Extract the file and import the project into your favorite IDE.

Structure of a Spring Boot Project

When you open the project, you will notice a standard directory structure:

• src/main/java: contains the source code of your application.
• src/main/resources: contains resources such as properties files, HTML templates and static files.
• src/test/java: contains your application's tests.
• pom.xml (for Maven projects) or build.gradle (for Gradle projects): contains the project configuration and dependencies.

Inside src/main/java, you will find a package with the name you defined when creating the project. Inside this package, there will be a class with the main method, which is the entry point of your Spring Boot application.

Creating a New Spring Boot Project

Here is an example of how to create a new Spring Boot project with a simple REST API:

1. Create a new project in Spring Initializr with Web, JPA, H2 and Lombok dependencies.
2. Import the project into your IDE.
3. Create a new package called model and inside it create a class User with some attributes like id, name and email. Use the Lombok annotations @Data and @Entity to reduce boilerplate code.
4. Create a package called repository and within it create an interface UserRepository that extends JpaRepository. This will provide CRUD methods for the User entity.
5. Create a package called controller and inside it create a class UserController. Use the @RestController and @RequestMapping annotations to indicate that this class will be a REST controller and to define the base path for the API.
6. Within UserController, create methods to handle CRUD operations, mapping each one to an HTTP request type (GET, POST, PUT, DELETE).
7. Use dependency injection to add an instance of UserRepository to your controller.
8. Run the project and test your API endpoints using a tool like Postman or cURL.

With these steps, you will have a basic REST API ready to be expanded and customized according to the needs of your project.

Conclusion

Spring Boot significantly simplifies the process of creating and configuring Spring applications, especially REST APIs. With Spring Initializr and the broad Spring ecosystem, you can quickly create robust and efficient projects. Remember to follow development best practices, such as separation of responsibilities, automated testing, and API documentation, to ensure your application is easy to maintain and scale.

When creating REST APIs with Spring Boot, you benefit from a series of automatic features, such as self-explanatory configuration, easy endpoint creation and integration with various tools.ments and frameworks that facilitate the development of modern and scalable applications. With a little practice and experimentation, you'll be able to create complete and efficient REST APIs that can be the backbone of modern web and mobile applications.