在依赖于非 Maven 库时将库部署到 Maven 存储库

Question

I run an open source library and am considering having it fully embrace Maven and upload it to to a central repository so that people can easily add it to their projects.

The problem is that it depends on a couple of older libraries that do not exist on any Maven repos. Currently, that means a pom file has to use the system scope of the dependency. I've also read about creating a local repository for the project to install the 3rd party libraries.

However, my impression is that neither of these approaches will work well when I deploy my library to a Maven repository. That is, if it depends on external "system" or local repositories, then when someone adds my library to their pom file, they're not actually done. They also have to download the 3rd party libraries and manually install them or add them to their own local repository.

What I'd like to have happen is for these couple of 3rd party libraries to simply be included in the jar file that I deploy to the central repository. That way, if someone adds my library to their pom file, they really are done and don't have to worry about getting and installing the 3rd party libraries. Is it possible to do that?

Answer 1

First off, I'll start by saying that you should back away as far as possible from the system scope. You can refer to this answer for more information.

A way to circumvent your problem is indeed to include in the deployed JAR all the libraries that aren't present in Maven Central. (Let's say you have installed those libraries in your local repository.) You can do that with themaven-shade-plugin , which is a plugin used to create uber jars. The attribute artifactSet controls what will be included in the shaded JAR. In the following snippet, only the two dependencies groupId:artifactId and groupId2:artifactId2 will be included.

<plugin>
  <artifactId>maven-shade-plugin</artifactId>
  <version>2.4.3</version>
  <executions>
    <execution>
      <phase>package</phase>
      <goals>
        <goal>shade</goal>
      </goals>
      <configuration>
        <artifactSet>
          <includes>
            <include>groupId:artifactId</include>
            <include>groupId2:artifactId2</include>
          </includes>
        </artifactSet>
      </configuration>
    </execution>
  </executions>
</plugin>

By default, the shaded JAR will replace your main artifact and this will be the JAR that will be deployed. The POM that will be deployed will not contain the dependency entries for the artifacts that were included in the shaded JAR , as such, a client depending on your deployed artifact won't be transitively-depending on them.