如何从 Maven 依赖项中获取 class 文件到 target\classes 文件夹

Question

Is there any sort of Maven plugin that allows me to copy the class files for a dependency into the target\classes folder for my project? Currently I have to manually open the jar file that has the dependencies extract the package that I need to copy over and then copy it into the target\class folder for my project.

I need a way to do those ideally within the pom.xml file but I haven't been able to find a solution that works. Any help would be appreciated, Thanks.

Answer 1

Use the maven-dependency-plugin. Here is an example of how you can extract the content of a dependency JAR:

    <project>
       [...]
       <build>
         <plugins>
           <plugin>
             <groupId>org.apache.maven.plugins</groupId>
             <artifactId>maven-dependency-plugin</artifactId>
             <version>3.1.2</version>
             <executions>
               <execution>
                 <id>unpack</id>
                 <phase>package</phase>
                 <goals>
                   <goal>unpack</goal>
                 </goals>
                 <configuration>
                   <artifactItems>
                     <artifactItem>
                       <groupId>junit</groupId>
                       <artifactId>junit</artifactId>
                       <version>3.8.1</version>
                       <type>jar</type>
                       <overWrite>false</overWrite>
                       <outputDirectory>${project.build.directory}/alternateLocation</outputDirectory>
                       <destFileName>optional-new-name.jar</destFileName>
                       <includes>**/*.class,**/*.xml</includes>
                       <excludes>**/*test.class</excludes>
                     </artifactItem>
                   </artifactItems>
                   <includes>**/*.java</includes>
                   <excludes>**/*.properties</excludes>
                   <outputDirectory>${project.build.directory}/wars</outputDirectory>
                   <overWriteReleases>false</overWriteReleases>
                   <overWriteSnapshots>true</overWriteSnapshots>
                 </configuration>
               </execution>
             </executions>
           </plugin>
         </plugins>
       </build>
       [...]
     </project>

Answer 2

This sounds like a terrible idea. If you want to include unpacked dependencies into your project, use the maven assembly plugin or the maven shade plugin.