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Here, spring-boot is mainly used out of the box, which can generate a program that runs independently and the plug-in docker-maven-plugin of maven

Here are the main steps

Build a simple springboot project to add docker-maven-plugin and write dockerfile practices to generate docker images

A simple Spring Boot project

Take spring boot 2.0 as an example

Add parament dependencies in pom.xml files

Org.springframework.boot spring-boot-starter-parent 2.0.0.RELEASE

Increase web and test dependencies

Org.springframework.boot spring-boot-starter-web org.springframework.boot spring-boot-starter-test test

Create a Controller with an index () method that returns: Hello Docker!

@ RestControllerpublic class Controller {@ RequestMapping ("/") public String index () {return "Hello Docker!";}}

Startup class

@ SpringBootApplicationpublic class Application {public static void main (String [] args) {SpringApplication.run (Application.class, args);}}

After adding, start the project. After starting successfully, the browser asks: http://localhost:8080/, the page returns: Hello docking, indicating that the configuration of the Spring Boot project is normal.

Add dcoker-maven-plugin

Add the Docker mirror prefix to the properties node of pom.xml

Springboot

Add the docker build plug-in to plugins

Org.springframework.boot spring-boot-maven-plugin com.spotify docker-maven-plugin 1.0.0 ${docker.image.prefix} / ${project.artifactId} src/main/docker / ${project.build.directory} ${project.build.finalNmae} .jar

Write Dockerfile

Create a Dockerfile file under the directory src/main/docker, and the Dockerfile file is used to explain how to build the image.

FROM openjdk:8-jdk-alpineVOLUME / tmpADD spring-boot-docker-1.0.jar app.jarENTRYPOINT ["java", "- Djava.security.egd=file:/dev/./urandom", "- jar", "/ app.jar"] EXPOSE 8080

This Dockerfile file is very simple. Build the Jdk basic environment, add Spring Boot Jar to the image, and simply explain:

FROM means to use the Jdk8 environment as the basic image. If the image is not local, VOLUME will be downloaded from DockerHub. VOLUME points to a directory of / tmp. Because Spring Boot uses the built-in Tomcat container, Tomcat uses / tmp as the working directory by default. The effect of this command is to create a temporary file under the / var/lib/docker directory of the host and link it to the / tmp directory ADD in the container, copy the file and rename ENTRYPOINT. In order to shorten the startup time of Tomcat, add the system attribute of java.security.egd to / dev/urandom as ENTRYPOINTEXPOSE indicates port 8080 to provide services.

Generate docekr image

You need a Docker environment to package your Spring Boot project.

Need three dependencies

Jdk environment mavendocker environment

Running java-version,mvn-version,docker version these commands does not report an error, which means the environment is ready.

Enter the project directory

Mvn package-Dmavne.test.skip=truejava-jar target/spring-boot-docker-1.0.jar

It works normally, which means there is nothing wrong with the jar package.

Then build the image

Mvn docker:build

The display of build success is successful.

Use docker images to view the built image

Run Mirror

Docker run-p 8080 8080-t springboot/spring-boot-docker

Then curl http://127.0.0.1:8080 can see that Hello docking is returned, indicating success.

The above is the whole content of this article, I hope it will be helpful to your study, and I also hope that you will support it.

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