Building a WAR project with unzipped JAR dependency?

Question

I have two projects, my-lib and my-webapp. The first project is a dependency of my-webapp. Thus, when ask Maven2 to build my WAR, the my-lib JAR is added in the WEB-INF/lib/ directory of the web application.

However, I want to have the my-lib JAR unzipped directly in the WEB-INF/classes directory, exactly as if the my-lib sources were contained in the project my-webapp.

In others words, instead of having the following WAR content:

my-webapp/
  ...
  WEB-INF/
    lib/
      my-lib-1.0.jar
      ... (others third libraries)

I want to have that:

my-webapp/
  ...
  WEB-INF/
    classes/
      my-lib files
    lib/
      ... (others third libraries)

Is there a way to configure the my-webapp or the Maven2 war plugin to achieve that?

Answer 1

As blaufish's answer says, you can use the maven-dependency-plugin's unpack mojo to unpack an artifact. However to avoid the jar appearing in WEB-INF/lib, you need to not specify it as a dependency, and instead configure the plugin to unpack specific artifacts.

The following configuration will unpack the contents of some.group.id:my-lib:1.0:jar into target/classes during the process-resources phase, even if the artifact is not defined as a dependency. Be careful when doing this though as there is potential to clobber your actual content, this can cause much debugging.

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-dependency-plugin</artifactId>
  <executions>
    <execution>
      <id>unpack-my-lib</id>
      <phase>process-resources</phase>
      <goals>
        <goal>unpack</goal>
      </goals>
      <configuration>
        <artifactItems>
          <artifactItem>
            <groupId>some.group.id</groupId>
            <artifactId>my-lib</artifactId>
            <version>1.0</version>
            <type>jar</type>
            <overWrite>false</overWrite>
          </artifactItem>
        </artifactItems>
        <outputDirectory>${project.build.outputDirectory}</outputDirectory>
        <overWriteReleases>false</overWriteReleases>
      </configuration>
    </execution>
  </executions>
</plugin>