Sharing Resources in Maven
Today I needed to figure out the best way to share resources across multiple maven modules. We have previously done it 2 different ways, neither of which I thought were very good. The first way was using a relative path to reach across to the modules resource directory (usually not a good practice in maven). It went something like this:
1 2 3 4 5 | <resources> <resource> <directory>../module1/src/main/resources</directory> </resource></resources> |
The second way was using the infamous maven assembly plugin. I typically avoid the assembly plugin like I avoid writing Assembly. Plus I prefer avoiding 100 extra lines of XML on something so trivial. Luckily, the Sonatype guys apparently knew this and have come up with a more efficient way of sharing resources using the maven-remote-resources-plugin. It has the advantages of requiring a lot less XML lifting and it's nicely integrated into the maven lifecycle. I did run into one small issue trying to get it to work. By default it only copies **/*.txt files from src/main/resources. For several minutes, I couldn't figure how why it wasn't working until I added an includes for **/*.xml. Then it worked perfectly. Here is the end result:
Creating a resource bundle
Add the following to your POM which is going to create the resource bundle.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | <plugin> <artifactid>maven-remote-resources-plugin</artifactid> <version>1.1</version> <executions> <execution> <goals> <goal>bundle</goal> </goals> <configuration> <includes> <include>**/*.xml</include> </includes> </configuration> </execution> </executions></plugin> |
You now should see the following message in your mvn output while running mvn clean install.
[remote-resources:bundle {execution: default}]
This produces a /target/classes/META-INF/maven/remote-resources.xml file which contains references to the resource files. For example,
1 2 3 | <remoteresources> <remoteresource>test.xml</remoteresource></remoteresources> |
Add the following to the POM which needs to consume the new resource bundle.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | <plugin> <artifactid>maven-remote-resources-plugin</artifactid> <version>1.1</version> <executions> <execution> <goals> <goal>process</goal> </goals> <configuration> <resourcebundles> <resourcebundle>com.lorenzen:lorenzen-core:${pom.version}</resourcebundle> </resourcebundles> </configuration> </execution> </executions></plugin> |
You now should see the following message in your mvn output while running mvn clean install.
[remote-resources:process {execution: default}]
You should now be able to look into your second modules /target/classes directory and see test.xml.
