Force Maven clean

I have a project with 2 profiles, because UAT and PROD use different versions of the same jar.

I hav开发者_运维问答e noticed that if i don't explicitly call mvn clean ... the deployed EAR will have BOTH UAT and PROD jars.

Is there a way in the POM to specify that Maven should always clean before any building?

Use the maven-clean-plugin with the initialize phase as given here

http://maven.apache.org/plugins/maven-clean-plugin/usage.html

<project>
  [...]
  <build>
    <plugins>
      <plugin>
        <artifactId>maven-clean-plugin</artifactId>
        <version>2.4.1</version>
        <executions>
          <execution>
            <id>auto-clean</id>
            <phase>initialize</phase>
            <goals>
              <goal>clean</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>
  [...]
</project>

Sure. Visit the Maven clean plugin usage page, they provide an example how to run the plugin automatically during build.

Please read up on the maven lifecycle especially the package lifecycle.

The maven clean plugin you use will probably allow you to define a clean goal at a particular pahse. You can also execute for example mvn clean install -P profile