create directory when needed in maven

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 开发者_运维知识库don't want to define a mkdir command in the pom.xml, since my project need to be system independent.

---

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.

---

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>

---

If you would like to prepare such folder structure somewhere in your project and then copy to place you want, use maven-resource plugin to do that:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-resources-plugin</artifactId>
   <executions>
       <execution>
           <id>copy-folder</id>
           <phase>package</phase>
           <goals>
               <goal>copy-resources</goal>
           </goals>
           <configuration>
               <outputDirectory>${project.build.directory}</outputDirectory>
               <resources>
                   <resource>
                    <filtering>false</filtering>
                    <directory>${project.basedir}/src/main/resources/folders</directory>
                   </resource>
               </resources>
           </configuration>
    </execution>
   </executions>
</plugin>