DockerDockerizing Applications
Dockerizing Spring Boot Web Application
Create a Docker image for a Spring Boot web app and run it with port mapping.
Spring Boot applications are a natural fit for Docker because they usually package into a single executable JAR.
Once the JAR is built, the Docker image only needs Java, the JAR file, the exposed port, and the startup command.
Build the Spring Boot app
Run:
mvn clean packageThe JAR is usually created inside target.
target/demo-0.0.1-SNAPSHOT.jarDockerfile
Create a Dockerfile in the project root:
FROM eclipse-temurin:17-jre
WORKDIR /app
COPY target/demo-0.0.1-SNAPSHOT.jar app.jar
EXPOSE 8080
CMD ["java", "-jar", "app.jar"]Change the JAR name to match your project.
Build the image
docker build -t spring-web-app:1.0 .Run the container
docker run -d -p 8080:8080 --name spring-web spring-web-app:1.0Open:
http://localhost:8080What to check if it fails
Check logs:
docker logs spring-webCommon problems:
- The JAR name in
COPYis wrong - The app uses a different port
- Maven build failed
- The container started and exited because the app crashed
- Environment variables are missing
For Spring Boot, Docker usually runs the final JAR. First make the JAR work, then package it into an image.
Written By: Shiva Srivastava
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