This calls exactly for the using the Maven JAR Plugin
For example, if you want to exclude everything under src/test/resources/
from the final jar, put this:
<build>
<plugins>
<!-- configure JAR build -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>2.3.1</version>
<configuration>
<excludes>
<exclude>src/test/resources/**</exclude>
</excludes>
</configuration>
</plugin>
...
Files under src/test/resources/
will still be available on class-path, they just won't be in resulting JAR.