create directory when needed in maven

Question

I am using maven-exec-plugin to generate java sources of Thrift. It invokes the external Thrift compiler and using -o to specify the output directory, "target/generated-sources/thrift".

The problem is neither maven-exec-plugin nor Thrift compiler automatically create the output directory, I have to manually create it. Is there a decent/portable way use create missing directories when needed? I don't want to define a mkdir command in the pom.xml, since my project need to be system independent.

Answer 1

Instead of the exec plugin, use the antrun plugin to first create the directory and then invoke the thrift compiler.

<plugin>   <artifactId>maven-antrun-plugin</artifactId>   <executions>     <execution>       <id>generate-sources</id>       <phase>generate-sources</phase>       <configuration>         <tasks>           <mkdir dir="target/generated-sources/thrift"/>           <exec executable="${thrift.executable}">             <arg value="--gen"/>             <arg value="java:beans"/>             <arg value="-o"/>             <arg value="target/generated-sources/thrift"/>             <arg value="src/main/resources/MyThriftMessages.thrift"/>           </exec>         </tasks>       </configuration>       <goals>         <goal>run</goal>       </goals>     </execution>   </executions> </plugin> 

You may also want to take a look at the maven-thrift-plugin.

Answer 2

You can define an ant task to do the job. Put the plugin declaration into your project's pom.xml. This will keep your project system-independent:

        <plugin>             <groupId>org.apache.maven.plugins</groupId>             <artifactId>maven-antrun-plugin</artifactId>             <executions>                 <execution>                     <id>createThriftDir</id>                     <phase>process-resources</phase>                     <configuration>                         <tasks>                             <delete dir="${thrift.dir}"/>                             <mkdir dir="${thrift.dir}"/>                         </tasks>                     </configuration>                     <goals>                         <goal>run</goal>                     </goals>                 </execution>             </executions>          </plugin>