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The Witcher
The Witcher

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Dockerizing a Spring Boot Application For Beginners

Prerequisites

  1. Install Docker on your machine (follow Docker's official installation guide).
  2. Basic Spring Boot Application - Make sure your Spring Boot app is ready to be containerized.

Step 1: Create a Simple Spring Boot Application

If you don't have an application already, create one using Spring Initializr (https://start.spring.io/).
Generate a basic Maven or Gradle project with dependencies you need (for example, Spring Web).

Step 2: Create a Dockerfile

In the root directory of your Spring Boot application, create a new file named Dockerfile (no extension).

# Use an official JDK runtime as a parent image
FROM openjdk:17-jdk-slim

# Add a label to identify the application
LABEL maintainer="your-email@example.com"

# Set the working directory in the container
WORKDIR /app

# Copy the application JAR file to the container
COPY target/your-application-name.jar app.jar

# Expose the port your app runs on
EXPOSE 8080

# Run the application
ENTRYPOINT ["java", "-jar", "app.jar"]
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Note: Replace your-application-name.jar with the actual name of your Spring Boot JAR file.

Step 3: Build the Application

In the terminal, navigate to the root directory of your Spring Boot project, then run:

./mvnw clean package
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This will build the application and generate a JAR file in the target/ directory.

Step 4: Build the Docker Image

Run the following command in the terminal from the root of your project (where the Dockerfile is located):

docker build -t my-spring-boot-app .
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Here:

  • -t my-spring-boot-app tags your image as my-spring-boot-app.
  • . specifies the current directory, where Docker will look for the Dockerfile.

Step 5: Run the Docker Container

Now that the image is created, you can run the container:

docker run -p 8080:8080 my-spring-boot-app
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Explanation:

  • -p 8080:8080 maps the container’s port 8080 to your machine’s port 8080.
  • my-spring-boot-app specifies the Docker image to run.

Your Spring Boot application should now be accessible on http://localhost:8080.

Step 6: Verify the Application

Open a browser or use a tool like curl to access the application and verify it's working:

curl http://localhost:8080
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Optional Steps

  1. Stop the Docker Container: Find the container ID with docker ps and stop it with:
   docker stop <container-id>
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  1. Clean Up Unused Images/Containers:
   docker system prune
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Summary

  1. Dockerfile - Define how to build the Docker image.
  2. Build - Create the Docker image.
  3. Run - Start the container and access the application.

This approach should give you a clear path to Dockerizing your Spring Boot application!

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Image of Docusign

🛠️ Bring your solution into Docusign. Reach over 1.6M customers.

Docusign is now extensible. Overcome challenges with disconnected products and inaccessible data by bringing your solutions into Docusign and publishing to 1.6M customers in the App Center.

Learn more