ant执行build failed
<?xml version="1.0" encoding="UTF-8"?>
<project basedir="." name="Fulfillment" default="compile">
<!-- all properties are in build.properties -->
<property file="${basedir}/build.properties"/>
<!--svn本身需要的运行库 -->
<path id="svnant.lib">
<pathelement location="${svnjavahl.jar}"/>
<pathelement location="${svnant.jar}"/>
<pathelement location="${svnClientAdapter.jar}"/>
</path>
<!--java EE 1.4 库 -->
<path id="javaEE1.4">
<fileset dir="${javaEE1.4.lib}">
<include name="**/*.jar"/>
</fileset>
</path>
<!--项目的classpath库 -->
<path id="project.classpath">
<pathelement location="${build.dir}"/>
<fileset dir="${lib.dir}"/>
</path>
<!--清理项目任务(干掉下载目录，tomcat原来的部署文件) -->
<target name="clear">
<delete dir="${work.space}"/>
<!--<delete dir="${tomcat.home}/work/Catalina/localhost/${ant.project.name}"/>
<delete dir="${tomcat.home}/webapps/${ant.project.name}"/>
<delete dir="${tomcat.home}/webapps/${ant.project.name}.war"/>-->
</target>
<!-- load the svn task -->
<taskdef name="svn" classname="org.tigris.subversion.svnant.SvnTask" classpathref="svnant.lib"/>
<!--svn同步任务-->
<target name="svn" depends="clear">
<mkdir dir="${work.space}"/>
<svn username="myname" password="mypwd" javahl="false">
<checkout url="${urlRepos}" destPath="${work.space}"/>
</svn>
</target>
<!--编译-->
<target name="compile" description="======compile project======">
<echo message="compile==========>${ant.project.name}: ${ant.file}"/>
<mkdir dir="${build.dir}"/>
<copy includeemptydirs="false" todir="${build.dir}">
<fileset dir="${java.source}" excludes="**/*.launch, **/*.java"/>
</copy>
<!--<copy includeemptydirs="false" todir="${build.dir}">
<fileset dir="${java.config}" excludes="**/*.launch, **/*.java"/>
</copy>-->
<javac includejavaruntime="true" debug="true" debuglevel="${debuglevel}" destdir="${build.dir}"
source="${source}" target="${target}" encoding="UTF-8">
<src path="${java.source}"/>
<!--<exclude name="config/"/>-->
<classpath>
<path refid="project.classpath">
</path>
<path refid="javaEE1.4">
</path>
</classpath>
</javac>
<!--<javac debug="true" debuglevel="${debuglevel}" destdir="${build.dir}" source="${source}" target="${target}"
encoding="utf-8">
<src path="${java.config}"/>
</javac>-->
</target>
<!--压缩，打包-->
<target name="war" depends="compile" description="======compress j2ee war file======">
<mkdir dir="${dist.dir}"/>
<!--compress j2ee war file-->
<war destfile="${war.file}" webxml="${web.dir}/WEB-INF/web.xml">
<fileset dir="${web.dir}"/>
<classes dir="${build.dir}"/>
<lib dir="${lib.dir}"/>
</war>
</target>
<!--shutdowntomcat-->
<!--<target name="shutdowntomcat" description="========shutdowntomcat===========">
<exec executable="${tomcat.home}/bin/shutdown.sh" failonerror="false"></exec>
<sleep seconds="10"/>
</target>-->
<!--startuptomcat-->
<!--<target name="startuptomcat" description="========startuptomcat===========">
<sleep seconds="5"/>
<exec executable="${tomcat.home}/bin/startup.sh" failonerror="false"></exec>
</target>-->
<!--部署到tomcat下面克-->
<!--<target name="deploy" depends="war">
<copy file="${war.file}" todir="${tomcat.home}/webapps"/>
</target>-->
<!--全自动无敌部署，启动关闭tomcat-->
<!--<target name="auto" depends="shutdowntomcat,deploy,startuptomcat">
<echo message="DONE!!!!"/>
</target>-->
</project>
执行报错：
BUILD FAILED
E:\ant\build.xml:4: Property work.space was circularly defined
