Maven复制依赖关系+阴影-类路径管理

Question

To package a maven project with its dependencies, among many solutions, one may use maven-dependency-plugin with its goal copy-dependencies to get the dependencies in a folder besides, or one may use maven-shade-plugin to get all the code in a single jar.

I actually do both: I choose to have external dependencies (eg apache commons) as external libs, and my own dependencies (I have a multi-module maven parent project) shaded into a unique jar.

And it works, except for the classpath. I copy-dependencies with option excludeGroupIds to exclude my own maven group id. I shade with option to include only my own maven group id. Before that, I jar with option to add classpath to the manifest. All set, it works. But my classpath also contains my own dependencies that were actually shaded in the final jar.

It is no big deal, because the result works even with this erroneous classpath. But I wonder if there is a simple means to have the correct classpath, in order not to expose my internal structure to my users.

Here is a basic example demonstrating the problem:

<groupId>com.foo.bar</groupId>
<artifactId>com.foo.bar.launcher</artifactId>

<dependencies>
    <dependency>
        <groupId>com.foo.bar</groupId>
        <artifactId>com.foo.bar.utils</artifactId>
        <version>0.0.1</version>
    </dependency>
    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-lang3</artifactId>
        <version>3.8.1</version>
    </dependency>
</dependencies>

<plugin>
    <artifactId>maven-jar-plugin</artifactId>
    <configuration>
        <archive>
            <manifest>
                <addClasspath>true</addClasspath>
                <classpathPrefix>lib/</classpathPrefix>
            </manifest>
        </archive>
    </configuration>
</plugin>
<plugin>
    <artifactId>maven-dependency-plugin</artifactId>
    <executions>
        <execution>
            <id>copy-dependencies</id>
            <phase>package</phase>
            <goals>
                <goal>copy-dependencies</goal>
            </goals>
            <configuration>
                <outputDirectory>${project.build.directory}/lib</outputDirectory>
                <excludeGroupIds>com.foo.bar</excludeGroupIds>
            </configuration>
        </execution>
    </executions>
</plugin>
<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-shade-plugin</artifactId>
    <executions>
        <execution>
            <goals>
                <goal>shade</goal>
            </goals>
            <configuration>
                <artifactSet>
                    <includes>
                        <include>com.foo.bar:*</include>
                    </includes>
                </artifactSet>
            </configuration>
        </execution>
    </executions>
</plugin>

The resulting manifest contains this: Class-Path: lib/com.foo.bar.utils-0.0.1.jar lib/commons-lang3-3.8.1.jar while the com.foo.bar.utils one does not exist.

Answer 1

If you look into the following mvnrepository link maven shade plugin depends upon maven dependency tree . As per the above pom.xml maven dependency plugin, you have excluded com.foo.bar dependency. You can omit the maven-dependency-plugin to create fat jar. It is not mandatory to use in case of shade plugin.

You can use the following command to check and copy all the dependencies used in the project.

mvn dependency:copy-dependencies

https://mvnrepository.com/artifact/org.apache.maven.plugins/maven-shade-plugin/3.2.1