Spring Boot CommandLineRunner Code Example

Spring Boot helps you quickly get started with building a Spring-based web app in no time. All you need to do is go to Eclipse IDE, create a new Spring Starter Project and that is it. This is provided you installed Eclipse plugin, Spring Tools (aka Spring IDE and Spring Tool Suite) by going to Help > Eclipse Marketplace… and searching for “spring tools” keyword.

Often, one wants to run a Spring Boot app as a Java application as like a traditional Java program and test different parts of their app.

In this post, you will get a template code for quickly getting started with Command Liner which would help you to execute your Spring boot app as a Java application.

Spring Boot App with CommandLineRunner

I create a spring started a project with the name as recruiterbot. I got the following code:

package com.vitalflux.rbot;

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

@SpringBootApplication
public class RecruiterbotApplication {

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

In order to work with command line, all you need to do is implement an interface CommandLineRunner. The following code represents the same.

@SpringBootApplication
public class RecruiterbotApplication implements CommandLineRunner {

    public static void main(String[] args) {
        SpringApplication app = new SpringApplication(RecruiterbotApplication.class);
        app.run(args);
    }

    @Override
    public void run(String... arg0) throws Exception {
        System.out.println("Hello World");
    }
}

To run the Spring Boot as Java application from within Eclipse, right-click on the program, RecruiterBotApplication and click Run As / Java Application.

References

• Application Runner or CommandLineRunner

Summary

In this post, you learned about getting started with Spring Boot app using CommandLineRunner.

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