【PMD】Can't find resource null. Make sure the resource is a valid file or URL or is on the CLASSPATH...

ant-xml配置文件如下

<?xml version="1.0" encoding="UTF-8"?>
<project name="svn-letu" basedir="." default="default">

<property name="pmd.dir" value="/opt/ant/lib"/>
<path id="pmd.dir">
<fileset dir="${pmd.dir}">
<include name="pmd-4.2.jar"/>
</fileset>
</path>

<target name="run-pmd">
<echo message="generate pmd report start ......." />
<taskdef name="pmd" classname="net.sourceforge.pmd.ant.PMDTask" classpathref="pmd.dir">
<classpath>
<pathelement path="/opt/ant/lib/pmd-4.2.jar"/>
</classpath>
</taskdef>
<pmd rulesetfiles="unusedcode" shortFilenames="true">
<formatter type="html" toFile="/opt//PMD/pmd_report.html" toConsole="true"/>
<fileset dir="/opt//checkout//src">
<include name="**/*.java"/>
</fileset>
</pmd>
</target>

<!-- project depends run -->
<target name="default" depends="run-pmd">
<echo message="generate pmd report finish ......." />
</target>

</project>

出现问题的原因如下：

使用pmd-bin-5.0.0版本的jar包不能找到资源文件，更换成pmd-bin-4.2这个版本的jar就正常生成报告了。