How to Run Spring Boot on Docker

Docker is a popular containerization tool that allows you to package and run your applications in a lightweight, portable environment. If you are working with Spring Boot, running your application on Docker can be a great way to simplify deployment and increase scalability. In this tutorial, we will show you how to run a Spring Boot application on Docker.

Prerequisites

Before we begin, make sure you have the following installed on your system:

Docker (version 17.06.0 or higher)
Java JDK 8 or higher
Maven (version 3.2 or higher)

Step 1: Create a Spring Boot application

If you don't have an existing Spring Boot application, you can create a new one using the Spring Initializr. To do this, go to start.spring.io and select your desired project options, such as language, version, packaging, and dependencies. Once you have made your selections, click the "Generate" button to download the project files.

Step 2: Build the Spring Boot application

Next, we need to build the Spring Boot application. To do this, navigate to the root directory of the project in the terminal and execute the following command:

$ mvn clean package

This will compile the code, run tests, and package the application into a JAR file.

Step 3: Create a Dockerfile

To run our application on Docker, we need to create a Dockerfile. This file describes the environment that our application will run in, including the base image, dependencies, and configuration.

Create a new file called "Dockerfile" in the root directory of your project and add the following code:

FROM openjdk:8-jdk-alpine
COPY target/my-application.jar app.jar
ENTRYPOINT ["java","-jar","/app.jar"]

This Dockerfile specifies that we want to use the "openjdk:8-jdk-alpine" image as the base image, copy our JAR file to the container, and then run the JAR file using the "java -jar" command.

Step 4: Build the Docker image

Now that we have a Dockerfile, we can build our Docker image. To do this, navigate to the root directory of your project in the terminal and execute the following command:

$ docker build -t my-application .

This will build the Docker image and tag it with the name "my-application".

Step 5: Run the Docker container

Finally, we can run our Spring Boot application on Docker by running the Docker container. To do this, execute the following command:

$ docker run -p 8080:8080 my-application

This will start the Docker container and map port 8080 on the host machine to port 8080 in the container.

Congratulations! You have successfully run a Spring Boot application on Docker. You can now deploy your Docker container to any environment that supports Docker, such as a Kubernetes cluster or a cloud-based container platform.

More examples:

• If your Spring Boot application requires external configuration files, you can use a volume to mount these files in the container at runtime.
• You can also use environment variables to pass configuration information to your Spring Boot application at runtime.

Related Searches and Questions asked:

How to Run Java App on Docker

How to Run Python on Docker

Containerize MongoDB Best Practices

Containerize Nginx Best Practices

That's it for this post. Keep practicing and have fun. Leave your comments if any.