Deploying a Spring Boot Application to Docker Using IDEA and Maven

IDEA is a powerful Java IDE, Spring Boot is the most popular microservice framework in the Java ecosystem, and Docker is the leading container technology; this guide shows how to combine them to deploy a Spring Boot application.

1. Preparation

Docker installation

Refer to the official Docker documentation: https://docs.docker.com/install/

Configure Docker remote connection port

vi /usr/lib/systemd/system/docker.service

Find the ExecStart line and append -H tcp://0.0.0.0:2375 to enable remote access.

Restart Docker

systemctl daemon-reload
systemctl start docker

Open firewall port

firewall-cmd --zone=public --add-port=2375/tcp --permanent

Install IDEA plugins and restart

(Images omitted for brevity.)

Connect to remote Docker

Edit the Docker configuration in IDEA, set the remote Docker address, and verify the connection; the remote containers and images are listed upon success.

2. Create Spring Boot project

Generate a Spring Boot project (e.g., via IDEA) and obtain the following project structure.

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>docker-demo</groupId>
    <artifactId>com.demo</artifactId>
    <version>1.0-SNAPSHOT</version>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.2.RELEASE</version>
        <relativePath />
    </parent>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <docker.image.prefix>com.demo</docker.image.prefix>
        <java.version>1.8</java.version>
    </properties>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <plugin>
                <groupId>com.spotify</groupId>
                <artifactId>docker-maven-plugin</artifactId>
                <version>1.0.0</version>
                <configuration>
                    <dockerDirectory>src/main/docker</dockerDirectory>
                    <resources>
                        <resource>
                            <targetPath/>
                            <directory>${project.build.directory}</directory>
                            <include>${project.build.finalName}.jar</include>
                        </resource>
                    </resources>
                </configuration>
            </plugin>
            <plugin>
                <artifactId>maven-antrun-plugin</artifactId>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <configuration>
                            <tasks>
                                <copy todir="src/main/docker" file="target/${project.artifactId}-${project.version}.${project.packaging}"/>
                            </tasks>
                        </configuration>
                        <goals>
                            <goal>run</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
    <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>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
    </dependencies>
</project>

Create Dockerfile (src/main/docker/Dockerfile)

FROM openjdk:8-jdk-alpine
ADD *.jar app.jar
ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]

application.properties (src/main/resources)

logging.config=classpath:logback.xml
logging.path=/home/developer/app/logs/
server.port=8990

DockerApplication.java

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

DockerController.java

@RestController
public class DockerController {
    static Log log = LogFactory.getLog(DockerController.class);
    @RequestMapping("/")
    public String index() {
        log.info("Hello Docker!");
        return "Hello Docker!";
    }
}

3. Build and run

Execute Maven packaging to produce the JAR, then use the Docker Maven plugin (or Docker CLI) to build the image, e.g., docker build -t docker-demo:1.1 ., and run the container with port and volume bindings:

docker run -d -p 8990:8990 -v /host/logs:/home/developer/app/logs --name docker-server docker-demo:1.1

After the container starts, access http://localhost:8990/ in a browser to see the "Hello Docker!" response, and view logs in the mounted host directory.

Thus, deploying a Spring Boot Java web application to Docker via IDEA and Maven becomes straightforward and efficient.