Introduction to Spring Boot
Spring Boot is the most popular Java-based framework that is built on the upgraded features of the Spring framework. It is used to make simple, easy to understand stand-alone and web-based applications.
What is Spring Boot?
Spring Boot is an open-source project spring framework developed by the Pivotal team (Spring team). It is built on the top of the Spring framework as it provides the RAD (Rapid Application Development) feature to the Spring framework. It is a combination of the Spring framework and third-party libraries that provides the ease of creating applications with fewer efforts. Unlike the Spring framework, Spring Boot does not require the XML-based or annotation-based configuration, as it auto-configures the Spring and third-party libraries.
The aim of the Spring Boot framework is to remove the XML-based configurations completely and reduces development, integration test time.
The goals of Spring Boot are listed below:
- To offer the Opinionated Development Approach completely.
- To provide most of the things implicitly or by default.
- To avoid writing multiple lines of code.
Need for Spring Boot
Some of the major factors of using the Spring Boot framework are listed below:
- It provides the flexibility to develop Java-based applications easily.
- It creates less time-consuming applications, as most of the things are managed by default.
- It does not require any XML-based or Java-based configuration, as it auto-configures the Spring and third-party libraries.
- It also provides powerful batch processing and flexible database transactions.
Components of Spring Boot
As we have discussed, the Spring Boot framework is an upgraded project of the Spring framework with some additional features and components. There are four major components of Spring Boot that are listed below:
- Spring Boot Starters
- Spring Boot AutoConfiguration
- Spring Boot CLI
- Spring Boot Actuator
Along with the above main components, there are two more additional components available in Spring Boot, i.e.,
- Spring Initializr
- Spring Boot IDEs
Spring Boot Starters
The Spring Boot Starters is one of the main components of the Spring Boot framework. It binds more than one dependency in a group. It also reduces the number of manually added dependencies by combining several dependencies into a single dependency. So, it adds a starter instead of specifying many dependencies.
For example, when we create a Spring MVC application, we require many dependencies such as,
- Spring Core
- Spring Web MVC
- Spring Web
Some more dependencies are needed along with the above dependencies. The manual addition of the dependencies makes a lot of fuss in the code. Here, Spring Boot came with the solution to this problem.
Spring Boot makes it easy as it only adds the root dependency or the starter dependency. When we add the starter dependency in the application, the Spring Boot automatically adds all the required dependencies to the application.
Spring Boot AutoConfiguration
The Spring Boot AutoConfiguration is also an essential component of the Spring Boot Framework. When we create any Spring application, we require a lot of configuration code like XML-based, Java-based, or annotation-based configuration code. In most of the applications, it creates a lot of confusion that results in time-consuming code.
Therefore, the Spring Boot AutoConfiguration cames into existence to solve the problem. It is responsible for reducing the Spring configuration. When creating a Spring Boot application, there is no need to define any configuration (XML- based) and reduces the use of an annotation-based configuration (almost no use). Using Spring Boot AutoConfiguration makes the program easy and executes fast as its configuration is not needed.
For example, if we use the “spring-boot-starter-web” starter in our application, the Spring Boot automatically configures all beans or classes.
Spring Boot CLI
The Spring Boot CLI (Command Line Interface) is a command line interface for Spring Boot based applications. We can run Spring Boot application on prompt using CLI. It is also used to test the Spring Boot applications from the command prompt. Using the Spring Boot CLI, we can also execute the Groovy code that has a similar Java-like syntax.
When running some Spring Boot applications through CLI, it internally uses the Spring Boot Starter and Spring Boot AutoConfiguration components to fix all the dependencies and run the applications.
Spring Boot Actuator
The Spring Boot Actuator is also an important component of the Spring Boot framework. It also works as the sub-project (tool) of the Spring Boot. It provides many features to Spring Boot framework, but mainly responsible for its two major features, i.e.,
- It provides the Management (HTTP) EndPoints to all Spring Boot applications.
- It also manages the production applications using these HTTP EndPoints.
The Spring Boot Actuator automatically provides the host name as “localhost” and port number as “8080” whenever we deploy our Spring Boot applications using the Spring Boot CLI. Here, we generally use the HTTP Request method (GET or POST) to represent the EndPoints using the Spring Boot Actuator.
The Spring Boot Actuator is mainly used for accessing the internal information of the application, such as metrics, dump, health, etc.
The Spring Initializr is a web-based interface for creating, configuring, and generating Spring-based applications. In other words, it is a tool that is used to start a JVM-based project with implementations quickly. It can create projects on various languages such as Groovy, Kotlin, and Java. It also provides the script (Maven or Gradle) to build the applications.
Spring Boot IDEs
The Spring Boot framework supports many IDEs like Eclipse, IntelliJ IDEA, Spring Tool Suite (STS), etc. that are used to create applications.
Advantages of Spring Boot
The main advantage of Spring Boot is that it consists of the Spring framework and Embedded HTTP server. But the XML-based and annotation-based configurations are degraded, as shown in the given diagram.
Some other advantages of the Spring Boot framework are given below:
- It easily develops Spring-based applications with Groovy and Java.
- It increases productivity and reduces the development time as most of the things are managed by default.
- It minimizes writing typical long code, such as XML-based and annotation-based configuration.
- It has made the integration of Spring Boot with other ecosystems like Spring Security, Spring Data, Spring JDBC, and ORM easy and smooth.
- It also provides Embedded HTTP servers such as Apache Tomcat, Apache Jetty, Undertow application server, and many others for deploying and testing Spring-based applications.
- It also offers several plugins for easily developing and testing Spring Boot applications using the build tools like Maven.
Limitation of Spring Boot
Some of the Spring Boot limitations are listed below:
- It contains some extra dependencies that are of no use, as it uses Spring Boot Starters (root dependencies).
- The unnecessary dependencies used in the applications result in huge and large size of the application.
- The conversion of Spring framework applications to Spring Boot applications is a bit time-consuming process.
Spring Boot Index
Spring Boot Tutorial