Including and Excluding Files From the WAR
It is possible to include or exclude certain files from the WAR file, by using the <packagingIncludes> and <packagingExcludes> configuration parameters. They each take a comma-separated list of Ant file set patterns. You can use wildcards such as ** to indicate multiple directories and * to indicate an optional part of a file or directory name.
Here is an example where we exclude all JAR files from WEB-INF/lib:
<project>
...
<build>
<plugins>
<plugin>
<artifactId>maven-war-plugin</artifactId>
<version>3.4.0</version>
<configuration>
<packagingExcludes>WEB-INF/lib/*.jar</packagingExcludes>
</configuration>
</plugin>
</plugins>
</build>
...
</project>
Sometimes even such wildcards are not enough. In these cases you can use regular expressions with the %regex[] syntax. Here is a real life use case in which this is used. In this example we want to exclude any commons-logging and log4j JARs, but we do not want to exclude the log4j-over-slf4j JAR. So we want to exclude log4j-<version>.jar but keep the log4j-over-slf4j-<version>.jar.
<project>
...
<build>
<plugins>
<plugin>
<artifactId>maven-war-plugin</artifactId>
<version>3.4.0</version>
<configuration>
<!--
Exclude JCL and LOG4J since all logging should go through SLF4J.
Note that we're excluding log4j-<version>.jar but keeping
log4j-over-slf4j-<version>.jar
-->
<packagingExcludes>
WEB-INF/lib/commons-logging-*.jar,
%regex[WEB-INF/lib/log4j-(?!over-slf4j).*.jar]
</packagingExcludes>
</configuration>
</plugin>
</plugins>
</build>
...
</project>
If you have more real life examples of using regular expressions, we'd like to know about them.