Web Development

Getting Started With Spring Boot Framework

Getting Started With Spring Boot

Chapter 1: Introduction to Spring Boot

Spring Boot is an open-source Java-Based framework which is used to create Micro Service.  Spring boot is developed by the pivotal team of Java Developers which is used to build stand-alone and production-ready spring applications.

If we talk by the definition then, Spring Boot is a utility project that aims to make it easier for the developers to build spring-based production-ready application and services with minimum fuss. You want to build the application faster and in the shortest way possible then you must use the command in your terminal.

Spring Boot Application Development

Command: out-of-the-box

Chapter1- Bootstarting Spring: Why is Spring Boot so popular?

This framework is around for over a decade and has found a place for itself as a standard framework for Java-based applications.  Well, there are many exciting new things that are taking part in the ecosystem spring has created, which includes many things such as reactive programming & client-side application development.

Spring Boot is the game-changer in the past year in the spring community. Spring Boot offers a new prototype or a pattern for developing Spring applications with a minimal amount of time.

Spring Boot vs. Spring Framework

With the new Spring Boot, you can develop Spring Applications developers will be able to develop the application with more stability, agility and they can give more of their focus on addressing other things like the functionality of the application, with a minimal thought that they have to configure it with spring. Spring Boot and Spring are two different things what spring boot helps developer with are it keeps spring aside so that the developers can do their stuff easily.

Spring Rebooted- What is the use of Spring Boot in Java?

Spring started as a very lite version alternative for JEE or J2EE (Java Enterprise Edition). Rather than developing component as Enterprise JavaBeans, Spring, on the other hand, offered a simple technique towards enterprise Java Development, for utilizing dependency injection and programming to gain the capabilities of Java Beans with plain old Java.

First Look at Spring

Let’s take an example that you are developing a simple Hello Word Program web application with the help of spring then, what will you do? Well, there are some things that you can probably do initially:

  • You need to have a proper project Structure which should be complete with Gradle build file or Maven build.
  • You will be needing a.XML file say web.xml which is stated a Web Application Initializer
  • You will be needing a controller class which will respond to the HTTP requests with “Hello World”
  • A spring configuration that will enable Spring MVC.
  • A server particularly for mobile application such as Tomcat, to deploy the application on.

This is interesting about the list mentioned above is the only single thing which is specific to developing the Hello World Functionality: the controller.

Now suppose for a moment all you need is a controller and it turns out that the groovy based controller which is shown in the image is a complete spring application.

A complete Groovy-based Spring application
1 @RestController
2 class HelloController {
3
4 @RequestMapping(“/”)
5 def hello() {
6 return “Hello World”
7 }
8
9 }

You will need no configuration even there is no configuration, no web.xml, No build specification, not even an application server. Well, to be honest, this is the entire spring application for you.

You will be needing a Command line for executing your spring application. A command-line could be the spring command line or (CLI) which is to be installed on your system on which you can run ‘Hello Controller’ command like this:

$ spring run HelloController.groovy

This is one of the simpler examples of controller used in Groovy because the simplicity of the Groovy language results well with the simplicity of Spring Boot.

Spring Boot essentials

  1. Starter Dependencies

It is a challenging task to build dependencies on a project’s build. What kind of library’s do you need? What group it is in? Which version you will need? Will the version you are having adjust well with other dependencies in the same project?

Spring Boot offers its help to developers with project dependency management with starters which are spring boot dependencies. Starter Dependencies are just Gradle Dependencies that takes advantage of transitive dependency resolution to sort the commonly used libraries under a handful of a feature defined dependencies.

Let’s take an example of building a REST API with the Spring MVC which only works with JSON resource representations. You should apply the declarative validation by converting a string into a value or JSR-303 specification and serve the application through the embedded Apache tomcat server. You will need a total of 6-8 dependencies in your Gradle Build to accomplish all the top discussed things.

There is more about the starter dependencies than just building it. The spring boot framework provides you with spring boot web service which enables your app to look like a web application, so you add the “web” starter.  You can add any type of starter for any need like if you want to add security to the build you can add security starter. In summation to it, you will no longer need to think about libraries

  1. CLI Interfaces

Well other than starter dependencies and auto-configuration, Spring Boot also offers an intuitive way to write codes for spring application quickly. The spring boot CLI offers the developers to write the application by just more than writing the app code.

The CLI takes advantages of the starter dependencies and auto-configuration which lets the developer focus on writing the code. It is not limited on this if you have noticed in the code which is pasted above it has no import code lines. But there are still questions like: How did the CLI know that what package Request Mapping and Rest Controller come from? And how did those classes end up in the classpath?

Well the answer to this question is that the CLI detects the types we are talking about in the previous paragraph and it knows which starter dependencies to add and remove to the classpath to make it work. Spring Boot CLI is an optional part of Spring Boot’s power. It also provides tremendous power and simplicity for spring boot development and introduces an unconventional development model.

  1. Configuration

In any Spring Application’s source code, you can find either XML configuration or Java Configuration which enables some supporting features and functionalities for the application. Let us take an example like you have written a code for an application which access a relational database with JDBC then might have just configured a Spring JDBC Template as a bean in the Spring application context.

The configuration code mostly will look like this:

1 @Bean
2 public JdbcTemplate jdbcTemplate(DataSource dataSource) {
3 return new JdbcTemplate(dataSource);
4 }

This is a very simple code configuration which creates a JDBC Template, injecting it with one dependency like a DataSource.  It also means that you will need to configure a DataSource bean so that the dependency will be met. Well, to complete this configuration scenario, like if you are about to configure an embedded H2 database as one of the DataSource beans:

1 @Bean
2 public DataSource dataSource() {
3 return new EmbeddedDatabaseBuilder()
4 .setType(EmbeddedDatabaseType.H2)
5 .addScripts(‘schema.sql’, ‘data.sql’)0
6 .build();
7 }

This helps the developer in bean configuration method to create an embedded database, specifying two SQL scripts to execute on the embedded database.

Spring Boot configures these configurations scenarios automatically. If your Spring Boot detects that you have an H2 database library in your application’s classpath, then it will configure a JDBC bean for you. If JDBC Template is in the classpath, then it will also configure a JDBC Template.

  1. Actuator

Well, the final Configuration piece for the Spring Boot is the Actuator. Here are the other parts of the spring boot simplify Spring Development, the actuator offers the ability to inspect the internal components of your Spring Application at the runtime.  By installing actuator you can inspect the inner working of your application including the details such as:

  • Beans that have been configured in the Spring App
  • Spring Boot auto-configuration decision making
  • Tracking the recent HTTP request which is handled by the spring application.
  • Different metrics regarding memory usage, cache collection, web requests, and data source usage.

The actuator uses the information in two different ways: first is via web endpoints or via shell interface. In other cases, it enables you to open a secure shell (SSH) in your Spring Application and enables you to write the command to inspect your application while it runs on the Terminal.

Well, we will explore the actual abilities of the above-listed dependencies in the coming chapter of this article.

Conclusion:

In this article, we came to understand how the Spring Boot works how you can install spring boot, what is the work of the Spring Boot dependencies and what is the command that you should use in the Spring Boot CLI. Java Development services are trending because everyone wants their websites and applications to be developed with the robustness it has to offer and on the other hand, it is way secure. In the coming chapter of Spring Boot we will discuss advantages of Spring Boot, Spring Boot: The Most Notable Features You Should Know. Stay tuned for upcoming app development with spring boot.

Rachit Mathur
About author

Rachit Mathur, being a Digital Marketer, he has an tremendous passion for writing. He found his way in Content Marketing. Curious about the tech world and having a technical background he love to explore and write about different technologies which also helps the company to grow faster.
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