Spring Boot Basics: Building a Java Web Application / ITech content

Contents:

• What is Spring Boot and how is it different from Spring?
• Quick Start
• Advantages of Spring Boot in Work
• Starting Spring Boot
• Creating Your First Web Application
• What's Next?

In the world of Java development, the Spring framework occupies a leading position for creating enterprise applications. When studying documentation, literature, or courses on Spring, in most cases, we immediately stumble upon Spring Boot. This tool significantly simplifies the development process, allowing you to quickly set up applications and reduce configuration time. Spring Boot offers many built-in features and automatic settings, making it an ideal choice for developers seeking efficiency and convenience.

We will discuss why Spring and Spring Boot are closely related, what are their differences, and what advantages Spring Boot offers. Finally, we will create a simple project for a practical demonstration.

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• What is Spring Boot and how is it different from Spring?
• Quick Start
• Advantages of Spring Boot in Work
• Launching Spring Boot
• Creating Your First Web Application
• What's Next?

What is Spring Boot and how is it different from Spring?

Spring is a popular framework for developing web applications and microservices in Java. It provides powerful tools for creating high-quality software. Spring Boot, in turn, is an extension of this framework that significantly simplifies the development process. With Spring Boot, developers can quickly create applications thanks to a set of utilities that automate Spring configuration and settings. This allows you to focus on business logic, minimizing time on routine tasks. Using Spring and Spring Boot provides a robust architecture and scalable applications, making these tools ideal for modern developers.

Spring Boot is designed to simplify and accelerate web application development. Unlike the traditional Spring Framework, it minimizes the need for complex configuration and provides a wealth of built-in tools that make writing and maintaining code easier. This makes Spring Boot an ideal choice for developers looking to quickly build robust and scalable web applications.

Unlike the basic framework, this tool has advanced capabilities. It supports more complex data structures, allowing developers to create more flexible and scalable applications. Furthermore, it offers built-in tools for optimizing performance and improving security, ensuring reliability and resilience under heavy loads. It's also worth noting that it has a wider range of components and libraries, significantly simplifying the development process and reducing project implementation time. As a result, this framework is suitable for both small and large projects, providing developers with everything they need to achieve successful results.

• package dependencies into standard starter packages;
• automatically configure applications using jar dependencies;
• use JavaConfig, which eliminates the need for XML;
• avoid multiple Maven imports and the version conflicts associated with it;
• provide powerful batch processing and manage RES endpoints;
• simplify integration with other Java frameworks such as JPA / Hibernate ORM, Struts, and so on;
• run embedded HTTP servers such as Tomcat and Jetty locally, simplifying the development and testing of web applications.

Spring Boot's widespread adoption is due to its convenience and functionality, which has made it a key development tool web applications based on the Spring framework.

Quick Start

We recommend starting your acquaintance with the library with the official documentation. Here you will find brief descriptions of the main annotations, classes, and methods, as well as practical examples of their application. After studying the basic information, it is advisable to move on to the extended documentation, which covers methods of working with JSON, logging, testing, and other important aspects in detail. This will help you gain a deeper understanding of the library's capabilities and effectively apply it in your projects.

Spring Boot offers an extensive guide for practical application of knowledge, which covers the development of various applications and their components. It is also important to refer to the official Spring framework documentation, which describes in detail not only aspects of working with Spring Boot but also interactions with other modules. This documentation is a valuable resource for developers, allowing them to deepen their understanding and effectively use the framework's capabilities.

Benefits of Spring Boot in Work

Spring Boot offers many built-in tools that significantly simplify and speed up the development process for programmers. These tools allow you to quickly configure applications, integrate various components, and minimize the amount of routine work. Using Spring Boot not only increases developer productivity but also contributes to the creation of higher-quality and more structured code.

Spring Boot offers the unique ability to use Spring Boot Starters, which are pre-configured dependencies. These starters significantly simplify the development process, allowing you to quickly integrate the necessary functionality into the project. Depending on the specific needs of your application, you can include one or more starter packages, which speeds up development and improves productivity.

Spring Boot Starter Web provides the necessary tools for developing web applications, including the Tomcat server and the Jackson library for JSON processing. Meanwhile, Spring Boot Starter Test includes classes and dependencies designed for testing, such as Mockito and Spring Boot Test. These starters simplify the process of setting up the environment, allowing developers to focus on writing code and creating high-quality applications.

Spring Boot Starters are convenient sets of dependencies that simplify the setup and configuration of Spring-based applications. They provide developers with the necessary libraries for quickly starting projects. Examples of using Spring Boot Starters can be found in the official documentation, which describes in detail the various starters and their applications. This allows you to effectively integrate the necessary functions and minimize the time spent on initial setup. Learning Spring Boot Starters will help developers better understand how to quickly and efficiently build applications using the Spring Framework.

A developer using Spring Boot has the ability to run built-in web servers such as Tomcat, Jetty, and Undertow, eliminating the need to spend time configuring external servers. If you need to use your own server, simply exclude standard dependencies and select the appropriate starter package. This makes the development process more flexible and convenient, allowing you to focus on writing code rather than configuring the server environment.

Spring Boot, like its parent framework, provides the ability to work with built-in modules that are easily integrated into applications. This significantly simplifies adding functionality and speeds up the development process. For example, using such modules allows developers to quickly configure security, interact with databases, and create RESTful APIs, making Spring Boot an ideal choice for creating modern web applications.

• Spring Data — allows you to work with various databases;
• Spring Boot Actuator — a function for monitoring and managing the created application.

All information about the built-in functions is available in the documentation, which is presented in the left menu column. You can find detailed descriptions and examples of each function to optimize your work with the tools.

Starting Spring Boot

To get started with Spring Boot, you need to create a new project and set up an integrated development environment (IDE). This will allow you to effectively use all the capabilities of the framework for developing Java applications.

The optimal way to create a development framework is to use the start.spring.io website. This online builder allows you to quickly and easily configure a Spring Boot-based project, which simplifies the development process and allows you to focus on implementing functionality.

Open the website.

On the left side of the screen, you can see various configuration options, including project settings. Since we're testing Spring Boot's ability to run, no changes to these settings are required. Please note that the site automatically suggests using the most current version of Spring Boot, which is 3.1.1 as of July 5th. This ensures you're working with the latest updates and improvements available in the framework.

On the right side, you can see the dependencies available for use in your project. To work effectively with your web application, you should click the «ADD DEPENDENCIES» button and add the Spring Web dependency. This will integrate the necessary tools and improve the functionality of your application, providing support for web technologies and simplifying development.

The added dependency is now displayed on the screen.

Click the «Generate» button to download an archive with a template for your project. This template will be useful later.

Unzip the archive and go to the directory. This folder contains several files.

• the mnvw file, which allows you to run a Maven project without installing it;
• the pom.xml file, which contains descriptions of all application dependencies;
• the java directory - the main directory of packages and classes;
• the resources directory, which stores resources: templates, settings files, localizations, and so on;
• application.properties - a file with project settings, located in the template subfolders.

All further work will be performed in this directory.

Popular code editors such as IntelliJ IDEA and Visual Studio Code are ideal for development using Spring Boot. These tools provide a convenient environment for writing code, debugging, and testing Spring Boot-based applications, which helps improve developer productivity. The choice of editor depends on user preferences and the specifics of the project.

Using Visual Studio Code, start by opening the editor and creating a new project. Then go to the Extensions section and search for "Spring Boot Extension Pack" to find the tools you need for Spring Boot development. Install this extension to simplify the process of creating and managing Spring Boot-based projects.

Install the required extension for Visual Studio Code. This will allow you to effectively work with Spring Boot and develop web applications. Thanks to Spring Boot integration, you can easily manage projects, configure the environment, and use the framework's functionality to create modern web applications.

In the downloaded archive, navigate to the src/main/java/com/example/demo directory and open the DemoApplication.java file. This file is the main class of your application and contains the main method, which launches the Spring Boot application. Make sure the project structure complies with standards to avoid possible errors during compilation and launch.

This file will contain all the necessary code. It serves as the start page when the service is launched. Here you can write Java code and integrate HTML and CSS elements to style the page. Using this file allows you to effectively organize your project structure and improve the appearance of your application.

We've configured the code editor to work with Spring Boot and created a project template. Now we can move on to creating the web application.

Creating Your First Web Application

Let's create a classic welcome application that will display a web page with the text "Hello, Skillbox Media Readers." To do this, replace the existing code in Visual Studio Code with the following:

At the beginning of the code, various classes and annotations are imported, which significantly simplify the development process. These elements provide convenient access to functionality and help optimize your workflow. Proper import of required libraries and components is the basis of effective programming, allowing you to focus on solving specific problems without wasting time.

• org.springframework.boot.SpringApplication — a class that is often used to bootstrap and start Spring applications;
• org.springframework.boot.autoconfigure.SpringBootApplication — denotes a configuration class that declares one or more @Bean methods and also triggers autoconfiguration and component scanning in the code;
• org.springframework.web.bind.annotation.GetMapping — annotation for mapping the results of an HTTP GET request to specific methods whose function is to handle events;
• org.springframework.web.bind.annotation.RequestParam — annotation that specifies that a method parameter should be bound to a parameter web request;
• org.springframework.web.bind.annotation.RestController is a convenience annotation that is itself annotated with @Controller and @ResponseBody.

The @RestController annotation in Spring denotes that the given class is a controller that handles HTTP requests and returns data in JSON or XML format. The @GetMapping («/hello») annotation specifies that the hello() method will be called to handle GET requests coming from http://localhost:8080/hello. This allows developers to create RESTful web services that easily integrate with client applications. Using these annotations simplifies route configuration and request handling, making code more understandable and maintainable.

The @RequestParam annotation in Spring specifies that the HTTP request must contain a value for the name parameter. If this parameter is missing, the default value, "Skillbox Media reader," will be used. This allows developers to conveniently manage input data and ensure the correct functioning of the application even if the expected parameters are missing.

The hello() method accepts a String name parameter and concatenates it with the word "Hello." This means that if you specify a name in the request, for example, "John," the response will be "Hello, John." You can also specify the name manually via the defaultValue parameter, which simplifies the process of using the method and makes it more versatile.

To run the code in the development environment, click the Run button. In Visual Studio Code, this button is called Run and Debug. This will allow you to run your code and debug it, if necessary. Make sure your project is configured correctly to ensure the startup process runs smoothly.

The integrated development environment (IDE) terminal will display information about the Spring application startup Boot.

If the code is written incorrectly, you will see error information instead of this window. However, everything is fine with us. Without closing your development environment (IDE), open a browser and navigate to http://localhost:8080/hello. This will allow you to test your code and ensure it functions correctly. Make sure the server is running and accessible to avoid connection errors.

Our caption is displayed on the screen.

Let's make the task more difficult and try displaying the reader's name instead of a general address. To do this, let's open the page, passing the name as the name parameter. This will create a more personalized experience for the user, making interaction with the content more intimate and unique.

The current URL looks like http://localhost:8080/hello?name=Anton. This address points to the local server where the page "hello" is requested with the parameter "name", the value of which is "8212" "Anton".

To improve SEO optimization, you can use more clear and descriptive URLs. For example, instead of using query parameters, it is worth using readable paths, such as http://localhost:8080/hello/anton. This makes the link more understandable for both users and search engines.

It is also recommended to add meta tags that describe the page content, as well as use headings and subheadings to structure the information. It's important to consider the keywords your audience might use to search for similar content.

Thus, an improved URL and optimized content will help increase the visibility of the page in search engines and make it more convenient for users.

We have achieved success. Instead of a general address to readers, we now use a specific person's name.

What's next?

Study the official documentation and guides with practical examples. This will create a solid foundation for further learning. After mastering these materials, you can move on to books that will deepen your knowledge and help consolidate the skills you have acquired.

• "Spring Boot in Action" by Craig Walls;
• "Learning Spring Boot 3.0" by Greg Turnquist.

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