如何使用Apache Ant提取部分文件名？

 <property name="filename" value="myfile.txt" />
 <property name="prefix" value="my" />
 <property name="suffix" value="txt" />
 <property name="basename" value="${filename}" />

 <target name="extract-filename">
    <basename property="basename" file="${filename}" />
   <propertyregex property="basename" input="${basename}" regexp="^${prefix}(.*)\.${suffix}$" replace="\1" />
    <echo message="Basename: ${basename}" />
  </target>
</project>