Spring Boot - Creating a standalone application example



Spring Boot - Creating a standalone application example

Spring Boot provides the various “Starters” for building standalone java application based on Spring framework. In this post we will use the spring-boot-starter for creating a standalone application which prints “Hello Spring Boot”.

Tools and technologies used for this application are-

  • Spring Boot 1.5.4.RELEASE
  • JavaSE 1.8
  • Maven 3.3.9
  • Eclipse Neon.3

 

Project Structure 

Review the spring boot project structure.

Spring Boot - Creating a standalone application example | BORAJI.COM

 

Jar dependencies

To create a standalone application in spring boot, you need to add the spring-boot-starter dependency in your pom.xml file. 

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter</artifactId>
</dependency>

Here is the complete pom.xml file.

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.boraji.tutorial.springboot</groupId>
  <artifactId>spring-boot-standalone-example</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <properties>
    <java.version>1.8</java.version>
  </properties>
  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.4.RELEASE</version>
  </parent>
  <dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter</artifactId>
    </dependency>
  </dependencies>
  <build>
    <plugins>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
      </plugin>
    </plugins>
  </build>
</project>

 

Spring Bean class

Create a HelloWorldBean class under com.boraji.tutorial.springboot.bean package as follows.

HelloWorldBean.java

package com.boraji.tutorial.springboot.bean;

import org.springframework.stereotype.Component;

@Component
public class HelloWorldBean {
   public void sayHello(){
      System.out.println("Hello Spring Boot!");
   }
}

 

Main class

To bootstrap spring boot application, create a main class annotated with @SpringBootApplication annotation.

MainApp.java

package com.boraji.tutorial.springboot;

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

import com.boraji.tutorial.springboot.bean.HelloWorldBean;

@SpringBootApplication
public class MainApp {
   public static void main(String[] args) {
      ApplicationContext ctx = SpringApplication.run(MainApp.class, args);

      HelloWorldBean bean = ctx.getBean(HelloWorldBean.class);
      bean.sayHello();
   }
}

 

Run application

Run the MainApp.java class as Java application i.e. go to Run→ Run as → Java Application

You can use the mvn spring-boot:run command to run the spring boot application.

After executing the main class, the console output will look like as follow.

Spring Boot - Creating a standalone application example | BORAJI.COM