如何用proguard混淆多模块spring-boot项目？

-injars <path-to-input-jars>
-outjars <path-to-output-jars>
-libraryjars <path-to-library-jars>

-keep public class com.example.module1.** {
    public protected *;
}

-keep public class com.example.module2.** {
    public protected *;
}

...

-keep public class com.example.modulen.** {
    public protected *;
}

<build>
    <plugins>
        <plugin>
            <groupId>com.github.wvengen</groupId>
            <artifactId>proguard-maven-plugin</artifactId>
            <version>2.3.1</version>
            <executions>
                <execution>
                    <phase>package</phase>
                    <goals>
                        <goal>proguard</goal>
                    </goals>
                </execution>
            </executions>
            <configuration>
                <proguardVersion>6.2.2</proguardVersion>
                <injar>${project.build.finalName}.jar</injar>
                <outjar>${project.build.finalName}-obfuscated.jar</outjar>
                <obfuscate>true</obfuscate>
                <options>
                    <option>-include proguard.cfg</option>
                </options>
            </configuration>
        </plugin>
    </plugins>
</build>

mvn clean package