How to develop your first maven plugin

Few weeks ago, i participated in a hackathon and my project was to write my first maven plugin ever. Unfortunately, i was not able to finish my hack in the same day and that was because i missed some small steps in the process, so i thought it would be worthwile to share what i discovered with the community. Here are the steps that i followed to create my first maven plugin.

1. creating the folder structure for our project by typing this maven comand: mvn archetype:create \ -DgroupId=sample.plugin \ -DartifactId=maven-hello-plugin \ -DarchetypeGroupId=org.apache.maven.archetypes \ -DarchetypeArtifactId=maven-archetype-mojo
2. creating the project: cd to the folder that was generated by the command above and type this command to generate th project files. mvn idea:idea or mvn eclipse:eclipse
3. open the project using your favorite IDE and then replace Mymojo.java content by the following code: package sample.plugin; import org.apache.maven.plugin.AbstractMojo; import org.apache.maven.plugin.MojoExecutionException; import java.io.IOException; /** * Goal which displays a hello message. * * @goal hello-message * * @phase package */ public class MyMojo extends AbstractMojo { /** * the hello message. * @parameter * @required */ private String message; public void execute() throws MojoExecutionException { getLog().info("Hello from :" + message); } }
4. installing the plugin: mvn clean install
5. executing the plugin: create another pom with different name, we'll call it here pom1.xml and then put this content in there.

      1:  <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

      2:    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">

      3:    <modelVersion>4.0.0</modelVersion>

      4:    <groupId>sample.plugin</groupId>

      5:    <artifactId>maven-hello-plugin</artifactId>

      6:    <packaging>maven-plugin</packaging>

      7:    <version>1.0-SNAPSHOT</version>

      8:    <name>maven-hello-plugin Maven Mojo</name>

      9:    <url>http://maven.apache.org</url>

     10:    <build>

     11:      <plugins>

     12:          <plugin>

     13:              <groupId>sample.plugin</groupId>

     14:              <artifactId>maven-hello-plugin</artifactId>

     15:              <version>1.0-SNAPSHOT</version>

     16:              <executions>

     17:                  <execution>

     18:                      <phase>package</phase>

     19:                      <configuration>

     20:                          <message>Jupiter</message>

     21:                      </configuration>

     22:                      <goals>

     23:                          <goal>

     24:                              hello-message

     25:                          </goal>

     26:                      </goals>

     27:                  </execution>

     28:              </executions>

     29:          </plugin>

     30:      </plugins>

     31:      </build>

     32:  
   

     33:  
   

     34:  
   

     35:      <dependencies>

     36:      <dependency>

     37:        <groupId>org.apache.maven</groupId>

     38:        <artifactId>maven-plugin-api</artifactId>

     39:        <version>2.0</version>

     40:      </dependency>

     41:      <dependency>

     42:        <groupId>junit</groupId>

     43:        <artifactId>junit</artifactId>

     44:        <version>3.8.1</version>

     45:        <scope>test</scope>

     46:      </dependency>

     47:    </dependencies>

     48:  </project>

   and then execute it: mvn -f pom1.xml package you'll see the message that we put in pom1.xml displayed in the logs.

You can download the project here.