Spring Boot

Figure 1: Spring Logo

Spring Boot is an open-source and Java-based framework. It is used to develop “Micro Services”. Micro Services is an architecture that enables developers to independently develop and deploy their services and each running service has its own process. The “Pivotal Team” created it. Spring applications are used to create stand-alone and production-grade applications. They offer the Spring platform and third-party libraries.

Spring Boot is a hybrid of the “Spring Framework” and “Embedded Servers”.

Figure 2: Spring Framework + Embedded Servers

Uses of Spring Boot Framework

• Employs the dependency injection approach.
• It has advanced database transaction management capabilities.
• It provides powerful batch processing and manages REST endpoints.
• It lowers the application’s cost and development time.
• It includes Embedded Servlet Container.
• It offers an annotation-based spring application.

How does it work?

Spring Boot configures your application automatically based on the dependencies that we added to the project with the @EnableAutoConfiguration annotation. The entry point of the spring boot application is the class that contains @SpringBootApplication annotation and the main method. By using the @ComponentScan annotation, Spring Boot automatically scans all of the project’s components.

Requirements

Your system needs to have the following minimum requirements to create a Spring Boot application.

• Java 7
• Maven 3.2
• Gradle 2.5

The Spring Boot Application’s entry point is the class that includes the @SpringBootApplication annotation. The main method of this class should be used to run the Spring Boot application. Auto-Configuration, Component Scan, and Spring Boot Configuration are all included in the @SpringBootApplication annotation.

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class DemoApplication {
   public static void main(String[] args) {
      SpringApplication.run(DemoApplication.class, args);
   }
}

Spring Boot CLI

Spring Boot CLI is a command-line tool that lets one run Groovy scripts. Using the Spring Boot Command Line Interface, this is the simplest way to build a Spring Boot program. In the command prompt, you can build, run, and evaluate the program.

you need to use the following two folders:

• spring-boot-cli-2.0.0.BUILD-SNAPSHOT-bin.zip
• spring-boot-cli-2.0.0.BUILD-SNAPSHOT-bin.tar.gz

In the command prompt, navigate to the Spring Boot CLI bin directory and execute the command spring –-version to ensure that Spring CLI is properly enabled. Create a simple groovy file that contains the Rest Endpoint script, save it as “hello.groovy” and run with spring boot CLI. Then required dependencies will download automatically and it will start the application in the Tomcat server.

@Controller
class Example {
   @RequestMapping("/")
   @ResponseBody
   public String hello() {
      "Hello Spring Boot"
   }
}

Finally, go to the browser and hit the URL (ex: http://localhost:8080/) and see the output.

Figure 3: localhost:8080

Advantages of Spring Boot

• It creates stand-alone Spring applications that can be started using Java -jar.
• It provides “starter” POMs with strong opinions to help us simplify our Maven configuration.
• Easy to understand and develop spring applications.
• Increases productivity.
• Reduces the development time.
• No requirement for XML configuration.
• Offers the number of plug-ins.
• Offers a CLI tool for developing and testing the Spring Boot application.

Goals of Spring Boot

• To avoid complex XML configuration.
• To develop a production-ready Spring application in an easier way.
• To reduce the development time and run the application independently.
• Avoids writing import statements.
• Avoids defining more Annotation Configuration.

References

1.https://www.tutorialspoint.com/spring_boot/spring_boot_quick_start.htm