The development of Docker technology provides a more convenient environment for micro-service landing. It is actually very simple to deploy Spring Boot with Docker. In this article, we will simply learn.
Start by building a simple Spring Boot project, then add Docker support to the project, and finally deploy the project.
A simple Spring Boot project
In Pom.xml, Spring Boot 2.0-related dependencies are used
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
. < version > 2.0.0 RELEASE < / version >
</parent>
Copy the codeAdd Web and test dependencies
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
Copy the codeCreate a DockerController with an index() method that returns Hello Docker!
@RestController
public class DockerController {
@RequestMapping("/")
public String index() {
return "Hello Docker!" ;
}
}
Copy the codeStart the class
@SpringBootApplication
public class DockerApplication {
public static void main(String[] args) {
SpringApplication.run(DockerApplication.class, args);
}
}
Copy the codeAfter the addition, start the project. After the successful startup, the browser will ask: http://localhost:8080/, and the page will return: Hello Docker! “Indicates that the Spring Boot project is correctly configured.
Spring Boot project adds Docker support
Add the Docker image name to pom.xml-properties
<properties>
<docker.image.prefix>springboot</docker.image.prefix>
</properties>
Copy the codeAdd Docker build plugins to plugins:
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<! -- Docker maven plugin -->
<plugin>
<groupId>com.spotify</groupId>
<artifactId>docker-maven-plugin</artifactId>
The < version > 1.0.0 < / version >
<configuration>
<imageName>${docker.image.prefix}/${project.artifactId}</imageName>
<dockerDirectory>src/main/docker</dockerDirectory>
<resources>
<resource>
<targetPath>/</targetPath>
<directory>${project.build.directory}</directory>
<include>${project.build.finalName}.jar</include>
</resource>
</resources>
</configuration>
</plugin>
<! -- Docker maven plugin -->
</plugins>
</build>
Copy the codeCreate a Dockerfile file under the directory SRC /main/docker. The Dockerfile file tells you how to build the image.
FROM openjdk:8-jdk-alpine
VOLUME /tmp
ADD spring - the boot - docker - 1.0. Jar app. The jar
ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]
Copy the codeBuild the Jdk base environment and add the Spring Boot Jar to the image.
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FROM: indicates that the Jdk8 environment is used as the base image. If the image is not local, it will be downloaded FROM DockerHub
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VOLUME, VOLUME points to a directory named/TMP. Since Spring Boot uses the built-in Tomcat container, Tomcat uses/TMP as its working directory by default. Create a temporary file in the /var/lib/docker directory on the host and link it to the/TMP directory in the container
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ADD, copy and rename the file
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Egd system attribute pointing to /dev/urandom as ENTRYPOINT to shorten Tomcat startup time
This completes the addition of the Docker dependency to the Spring Boot project.
Build a packaging environment
We need a Docker environment to package the Spring Boot project. It is very troublesome to build a Docker environment on Windows, so I take Centos 7 as an example.
Install the Docker environment
The installation
yum install docker
Copy the codeOnce the installation is complete, use the following command to start the Docker service and set it to boot:
ervice docker start
chkconfig docker on
CentOS 7 supports the new systemd syntax, which is as follows:
systemctl start docker.service
systemctl enable docker.service
Copy the codeUse the Docker China accelerator
vi /etc/docker/daemon.json
# after adding:
{
"registry-mirrors": ["https://registry.docker-cn.com"],
"live-restore": true
}
Copy the codeRestart Docker
systemctl restart docker
Copy the codeIf docker version is displayed, the installation is normal.
Install the JDK
Yum -y install Java -- 1.8.0 comes with its *
Copy the codeConfigure environment variables open vim /etc/profile add some content
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Export JAVA_HOME = / usr/lib/JVM/Java -- 1.8.0 comes with its 1.8.0.161-0. B14. El7_4. X86_64
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export PATH=$PATH:$JAVA_HOME/bin
Copy the codeAfter the modification is complete, make the modification take effect
source /etc/profile
Copy the codeRun the Java -version command to return the version information.
Install MAVEN
Download: http://mirrors.shu.edu.cn/apache/maven/maven-3/3.5.2/binaries/apache-maven-3.5.2-bin.tar.gz
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# # decompression
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The tar VXF apache maven -- 3.5.2 - bin. Tar. Gz
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# # mobile
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The mv apache maven -- 3.5.2 / usr/local/maven3
Copy the codeModify the environment variable by adding the following lines to /etc/profile
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MAVEN_HOME=/usr/local/maven3
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export MAVEN_HOME
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export PATH=${PATH}:${MAVEN_HOME}/bin
Copy the codeRemember to execute source /etc/profile for the environment variables to take effect.
Run the MVN -version command to return the version information.
The entire build environment is now configured.
Deploy the Spring Boot project using Docker
Copy the project spring-boot-Docker server into the project path for packaging test.
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# packaged
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mvn package
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# start
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Java - jar target/spring - the boot - docker - 1.0. The jar
Copy the codeAfter seeing the Boot log of Spring Boot, the environment configuration is ok. Next, we use DockerFile to build the image.
mvn package docker:build
Copy the codeThe first build may be a bit slow, but it is successful when you see the following:
.
Step 1 : FROM openjdk:8-jdk-alpine
---> 224765a6bdbe
Step 2 : VOLUME /tmp
---> Using cache
---> b4e86cc8654e
ADD spring-boot-docker-1.0.jar app.jar
---> a20fe75963ab
Removing intermediate container 593ee5e1ea51
Step 4 : ENTRYPOINT java -Djava.security.egd=file:/dev/./urandom -jar /app.jar
---> Running in 85d558a10cd4
---> 7102f08b5e95
Removing intermediate container 85d558a10cd4
Successfully built 7102f08b5e95
[INFO] Built springboot/spring-boot-docker
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 54.346s
[INFO] Finished at: 2018-03-13T16:20:15+08:00
[INFO] Final Memory: 42M/182M
[INFO] ------------------------------------------------------------------------
Copy the codeUse the docker images command to view the built images:
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docker images
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REPOSITORY TAG IMAGE ID CREATED SIZE
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Springboot /spring-boot-docker latest 99ce9468DA74 6 seconds ago 117.5 MB
Copy the codeSpringboot /spring-boot-docker is the image we built and the next step is to run it
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docker run -p 8080:8080 -t springboot/spring-boot-docker
Copy the codeAfter the startup is complete, we use Docker PS to view the running image:
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docker ps
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CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
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049570DA86a9 Springboot /spring-boot-docker "java-djava. security" 30 seconds ago Up 27 seconds 0.0.0.0:8080->8080/ TCP determined_mahavira
Copy the codeCan see that we build the container is running, access to a browser: http://192.168.0.x:8080/, to return
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Hello Docker!
Copy the codeSuccessful deployment of the Spring Boot project using Docker!
The sample code: https://github.com/ityouknow/spring-cloud-examples
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