How to create custom zip file including dependencies using Maven

I'm new to Maven and need to create a "custom" zip which basically contains:

A jar with my classes
Some (but not all) the dependencies I use to build: these are declared within Maven (e.g. these are not local copies manages within the project)

The desired ZIP file will have this structure:

META-INF/
- some-custom- descriptor.xml
lib/
- myLib.jar
- dependency1.jar
- dependency2.jar

So far I understand that the assembly plugin is the tool of trade but I don't get how to tell to perform the two steps:

create the jar for the binaries
add this jar together with some specific dependencies

Solution

I'm not sure if i unterstood everything. But i think you must first copy the dependencies(there are not inside the jar after)

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-jar-plugin</artifactId>
    <configuration>
        <archive>
           <manifest>
                <addClasspath>true</addClasspath>
                <mainClass>com.demo.App</mainClass>
                <classpathPrefix>lib/</classpathPrefix>
            </manifest>
        </archive>
    </configuration>
</plugin>
<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-dependency-plugin</artifactId>
    <executions>
        <execution>
            <id>copy-dependencies</id>
                <phase>package</phase>
                <goals>
                    <goal>copy-dependencies</goal>
                </goals>
                <configuration>
                    <includeScope>runtime</includeScope>
                    <outputDirectory>${project.build.directory}/lib/</outputDirectory>
                    <excludeScope>test</excludeScope>
                </configuration>
            </execution>
     </executions>
</plugin>

After that you can use the assembly plugin with a descriptor xml file like this:

<assembly>
    <id>zip</id>
    <formats>
        <format>zip</format>
    </formats>
    <includeBaseDirectory>false</includeBaseDirectory>
    <fileSets>
        <fileSet>
            <directory>${project.build.directory}/lib</directory>
            <outputDirectory>lib</outputDirectory>
        </fileSet>
        <fileSet>
            <directory>${project.build.directory}</directory>
            <outputDirectory></outputDirectory>
            <includes>
                <include>*.jar</include>
            </includes>
        </fileSet>
    </fileSets>
</assembly>