Maven plugin - smallest example

Posted by Monik, 25 March 2014.

Programming Maven

Table of contents

• Maven Plugins
  • 1. Define the plugin
  • 2. Add the plugin to another project
  • 3. Run the plugin
  • 4. Attach the plugin to a build lifecycle phase
• Maven Archetypes

Maven Plugins

• the properties to configure are defined in plugin goals
• the versions of dependencies in the plugin override the dependency versions of the project
• configuration can be placed:
• under the plugin node - it is the global plugin configuration
• under the executions/execution node - it is the configuration for this particular execution

Below are the minimal sample steps of developing a Maven plugin:

1. Define the plugin

package sample.plugin;

import org.apache.maven.plugin.AbstractMojo;
import org.apache.maven.plugin.MojoExecutionException;
import org.apache.maven.plugins.annotations.Mojo;

/**
 * Says "Hi" to the user.
 *
 */
@Mojo( name = "sayhi")
public class GreetingMojo extends AbstractMojo
{
    public void execute() throws MojoExecutionException
    {
        getLog().info( "Hello, world." );
    }
}

<project>
  <modelVersion>4.0.0</modelVersion>

  <groupId>sample.plugin</groupId>
  <artifactId>hello-maven-plugin</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>maven-plugin</packaging>

  <name>Sample Parameter-less Maven Plugin</name>

  <dependencies>
    <dependency>
      <groupId>org.apache.maven</groupId>
      <artifactId>maven-plugin-api</artifactId>
      <version>2.0</version>
    </dependency>
  </dependencies>
</project>

2. Add the plugin to another project

<build>
    <plugins>
      <plugin>
        <groupId>sample.plugin</groupId>
        <artifactId>hello-maven-plugin</artifactId>
        <version>1.0-SNAPSHOT</version>
      </plugin>
    </plugins>
</build>

3. Run the plugin

mvn sample.plugin:hello-maven-plugin:1.0-SNAPSHOT:sayhi

mvn hello:sayhi

4. Attach the plugin to a build lifecycle phase

<build>
    <plugins>
      <plugin>
        <groupId>sample.plugin</groupId>
        <artifactId>hello-maven-plugin</artifactId>
        <version>1.0-SNAPSHOT</version>
        <executions>
          <execution>
            <phase>compile</phase>
            <goals>
              <goal>sayhi</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>

Maven Archetypes

For example the maven-archetype-quickstart plugin we run like this:

>mvn archetype:generate
-DgroupId=com.companyname.bank
-DartifactId=consumerBanking
-DarchetypeArtifactId=maven-archetype-quickstart
-DinteractiveMode=false</div>

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