Dockerizing a Spring Boot Application

This project demonstrates how to containerize a Spring Boot application using Docker. The Dockerfile provided allows you to build and run a Spring Boot application in a Docker container, ensuring consistent environments for development, testing, and production.

Project Structure

.
├── src/ # Source code of the Spring Boot application
├── pom.xml # Maven project configuration file
└── Dockerfile # Dockerfile for building the Docker image

Prerequisites

• Docker installed on your machine.

Dockerfile Overview

This project uses a multi-stage Dockerfile to build and package the Spring Boot application:

1. Build Stage:

   • Uses the maven:3.8.3-openjdk-17 image to build the project.
   • Copies the source code and pom.xml into the container.
   • Runs mvn clean package to build the JAR file.

2. Package Stage:

   • Uses the openjdk:17 image to create a lightweight container.
   • Copies the JAR file from the build stage into the container.
   • Exposes port 8080.
   • Sets the user to 10014 for running the application.
   • Defines the entry point to run the Spring Boot application using the JAR file.

Building the Docker Image

To build the Docker image, navigate to the directory containing the Dockerfile and run the following command:

docker build -t springboot-docker .

Running the Docker Container

After building the Docker image, you can run the container using:

docker run -d -p 8080:8080 springboot-docker

This command will run the Spring Boot application in a Docker container and map port 8080 of the container to port 8080 on your host machine.

Testing the Application

The application includes a simple REST controller that responds with a "Hello World" message. To test the application:

1. Open your web browser or use a tool like curl or Postman.
2. Navigate to the following URL:

http://localhost:8080/hello/message

3. You should see the following response:

Hello World

This confirms that the application is running successfully in the Docker container.