Setting up a spring boot application
Follow the steps mentioned below to dockerize the spring boot application.
Step 1: Create a skeleton application using https://start.spring.io.
Step 2: Now create a maven project with the following configuration. After entering all the details, click on the ‘GENERATE’ button to download the project.
Step 3: Extract the zipped file.
Now, open it in an IDE of your choice.
Spring Boot buildpacks
Dockerfiles and manual configuration are not required when pack the Spring Boot apps into the container images thanks to Spring Boot buildpacks. It allow developers to take advantage of automatically image generation specific to their Spring Boot projects, freeing them up to concentrate on writing. These buildpacks automatically identify the prerequisites for the application, including runtime parameters and dependencies, and put everything together to make a container image that is suitable for production. This increases developer productivity, streamlines the containerization process, and improves consistency between deployments.
Step 4: Below one is the dependency to create docker image with the buildpacks. Now we need to add below Maven plugin in our pom.xml file.
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
Step 5: Open the base java file of the project and add a new controller to the base class of the application.
@RequestMapping("/")
public String home() {
return "Dockerizing Spring Boot Application";
}
Step 6: Now, add the @RestController annotation and import the required packages. In the end, your Application.java file should look like this.
package com.docker.spring;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@SpringBootApplication
@RestController
public class Application {
@RequestMapping("/")
public String home() {
return "Dockerizing Spring Boot Application";
}
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
Step 7: Now start the application by running the following command,
$ ./mvnw spring-boot:run
Step 8: Navigate to http://localhost:8080 to test the application.
Project Structure
This is how the project structure should look at this point,
How To Dockerize A Spring Boot Application With Maven ?
Docker is an open-source containerization tool used for building, running, and managing applications in an isolated environment. A container is isolated from another and bundles its software, libraries, and configuration files. In this article, to dockerize a Spring Boot application for deployment purposes, we will learn how to create a spring boot app, and how to create a docker image for the spring boot app and we will run it on the docker container.
Prerequisites: Before continuing any further, please ensure that node and docker are installed on your machine. If required, visit the Java Installation Guide or the Docker Installation Guide.
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