Introduction to Spring Boot

Spring is a popular framework for building scalable applications. For web development, Spring provides the Spring MVC module, widely used to create robust web applications. However, one significant drawback of traditional Spring projects is the time-consuming configuration process, which can overwhelm new developers.

Making a Spring application production-ready takes time, especially for beginners. The solution to this complexity is Spring Boot. Built on top of the Spring framework, Spring Boot offers all the features of Spring while significantly simplifying configuration and setup. Developers love Spring Boot for its rapid, production-ready environment that allows them to focus on business logic rather than struggling with setup and configuration.

Spring Boot is a microservice-based framework, enabling developers to create production-ready applications quickly. The only prerequisite for using Spring Boot is a basic understanding of the Spring framework. If you need to revisit Spring concepts, make sure to review foundational materials.

Features of Spring Boot #

Spring Boot builds on the conventional Spring framework, providing a simplified, more efficient development process. Here are its key features:

1. Avoids Heavy XML Configuration: Unlike traditional Spring MVC projects, Spring Boot uses auto-configuration. For example, integrating Hibernate (an ORM tool) only requires adding annotations such as @Table on entity classes and @Column for table columns.
2. Easy Creation and Maintenance of REST APIs: With Spring Boot, creating REST endpoints is straightforward. Use the @RestController annotation on controller classes and @RequestMapping to define routes.
3. Embedded Tomcat Server: Spring Boot includes an embedded Tomcat server, eliminating the need for manual installation. This simplifies deployment and development.
4. Effortless Deployment: Spring Boot allows seamless creation of JAR or WAR files that can be directly deployed to Tomcat servers or cloud environments.
5. Microservice-Based Architecture: Spring Boot facilitates microservice development, enabling the creation of modular, independent services. For example, a hospital management system could include microservices for patient registration, billing, and database management. Microservices are easier to debug, deploy, and maintain compared to monolithic systems.

Evolution of Spring Boot #

Spring Boot was introduced in response to a Jira request in October 2012 by Mike Youngstrom, seeking a simpler way to bootstrap Spring applications. By early 2013, Spring Boot was under development, and its first version, Spring Boot 1.0, was released in April 2014.

Subsequent versions followed:

• Spring Boot 1.1: June 2014
• Spring Boot 1.2: March 2015
• Spring Boot 1.3: December 2016
• Spring Boot 1.4: January 2017
• Spring Boot 1.5: February 2017

Spring Boot Architecture #

To understand Spring Boot’s architecture, let’s explore its layers and components:

Layers in Spring Boot:

1. Presentation Layer: Handles the user interface (UI) or views.
2. Data Access Layer: Manages database operations such as Create, Retrieve, Update, and Delete (CRUD).
3. Service Layer: Contains business logic and interacts with the Data Access Layer.
4. Integration Layer: Facilitates communication between different web services.

Additional components include utility classes, validators, and view classes. All services are implemented in their respective classes and accessed via dependency injection.

Spring Boot Workflow:

1. A client sends an HTTP request (e.g., GET or POST).
2. The request is handled by a controller, which maps the request to the appropriate route.
3. The controller invokes the service layer for business logic.
4. The service layer processes data from the database (mapped using JPA with entity classes).
5. If no errors occur, a response (e.g., JSP or JSON) is returned to the client.

How Spring Boot Simplifies Development #

In traditional Spring MVC, data access requires DAO and DAOImpl classes. In Spring Boot, these are replaced with repository interfaces, simplifying CRUD operations.

Setting Up Spring Boot #

Follow these steps to set up a Spring Boot application:

1. Install Java JDK: Download and install the Java JDK from Oracle’s official site.
2. Set Up Spring Tool Suite (STS): Download and install STS, an IDE tailored for Spring development.
3. Create a New Spring Starter Project:
   • Open STS and navigate to File → New → Spring Starter Project.
   • Fill in the project details and add necessary dependencies.
   • Click Finish to create the project.
4. Configure Application Properties: Edit the application.properties file to customise your application’s behaviour, such as database configurations or server ports.
5. Run the Main Application: Locate the main class (annotated with @SpringBootApplication) and run it as a Java application. This will start the embedded Tomcat server and host your application.

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