Best practices for copying files with Maven

Question

<build>
    <plugins>
        ...
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-resources-plugin</artifactId>
            <version>2.3</version>
        </plugin>
    </plugins>
    <resources>
        <resource>
            <directory>src/main/java</directory>
            <includes>
                <include> **/*.properties</include>
            </includes>
        </resource>
    </resources>
    ...
</build>

Don't shy away from the Antrun plugin. Just because some people tend to think that Ant and Maven are in opposition, they are not. Use the copy task if you need to perform some unavoidable one-off customization:

<project>
  [...]
  <build>
    <plugins>
      [...]
      <plugin>
        <artifactId>maven-antrun-plugin</artifactId>
        <executions>
          <execution>
            <phase>deploy</phase>
            <configuration>
              <target>

                <!--
                  Place any Ant task here. You can add anything
                  you can add between <target> and </target> in a
                  build.xml.
                -->

              </target>
            </configuration>
            <goals>
              <goal>run</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>
  [...]
</project>

In answering this question, I'm focusing on the details of what you asked. How do I copy a file? The question and the variable name lead me to a larger questions like: "Is there a better way to deal with server provisioning?" Use Maven as a build system to generate deployable artifact, then perform these customizations either in separate modules or somewhere else entirely. If you shared a bit more of your build environment, there might be a better way - there are plugins to provision a number of servers. Could you attach an assembly that is unpacked in the server's root? What server are you using?

Again, I'm sure there's a better way.

In order to copy a file use:

        <plugin>
            <artifactId>maven-resources-plugin</artifactId>
            <version>3.1.0</version>
            <executions>
                <execution>
                    <id>copy-resource-one</id>
                    <phase>install</phase>
                    <goals>
                        <goal>copy-resources</goal>
                    </goals>

                    <configuration>
                        <outputDirectory>${basedir}/destination-folder</outputDirectory>
                        <resources>
                            <resource>
                                <directory>/source-folder</directory>
                                <includes>
                                    <include>file.jar</include>
                                </includes>
                            </resource>
                        </resources>
                    </configuration>
                </execution>
           </executions>
        </plugin>

In order to copy folder with sub-folders use next configuration:

           <configuration>
              <outputDirectory>${basedir}/target-folder</outputDirectory>
              <resources>          
                <resource>
                  <directory>/source-folder</directory>
                  <filtering>true</filtering>
                </resource>
              </resources>              
            </configuration>  

For a simple copy-tasks I can recommend copy-rename-maven-plugin. It's straight forward and simple to use:

<project>
  ...
  <build>
    <plugins>
      <plugin>
        <groupId>com.coderplus.maven.plugins</groupId>
        <artifactId>copy-rename-maven-plugin</artifactId>
        <version>1.0</version>
        <executions>
          <execution>
            <id>copy-file</id>
            <phase>generate-sources</phase>
            <goals>
              <goal>copy</goal>
            </goals>
            <configuration>
              <sourceFile>src/someDirectory/test.environment.properties</sourceFile>
              <destinationFile>target/someDir/environment.properties</destinationFile>
            </configuration>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>
</project>

If you would like to copy more than one file, replace the <sourceFile>...</destinationFile> part with

<fileSets>
  <fileSet>
    <sourceFile>src/someDirectory/test.environment.properties</sourceFile>
    <destinationFile>target/someDir/environment.properties</destinationFile>
  </fileSet>
  <fileSet>
    <sourceFile>src/someDirectory/test.logback.xml</sourceFile>
    <destinationFile>target/someDir/logback.xml</destinationFile>
  </fileSet>                
</fileSets>

Furthermore you can specify multiple executions in multiple phases if needed, the second goal is "rename", which simply does what it says while the rest of the configuration stays the same. For more usage examples refer to the Usage-Page.

Note: This plugin can only copy files, not directories. (Thanks to @james.garriss for finding this limitation.)

The maven dependency plugin saved me a lot of time fondling with ant tasks:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-dependency-plugin</artifactId>
    <executions>
        <execution>
            <id>install-jar</id>
            <phase>install</phase>
            <goals>
                <goal>copy</goal>
            </goals>
            <configuration>
                <artifactItems>
                    <artifactItem>
                        <groupId>...</groupId>
                        <artifactId>...</artifactId>
                        <version>...</version>
                    </artifactItem>
                </artifactItems>
                <outputDirectory>...</outputDirectory>
                <stripVersion>true</stripVersion>
            </configuration>
        </execution>
    </executions>
</plugin>

The dependency:copy is documentend, and has more useful goals like unpack.