当需要用到外部包时，例如Oracle的classes12.jar等
用：
<?xml version= "1.0 " encoding= "UTF-8 "?>
<project name= "HelloAnt " default= "dist " basedir= ". ">
<!-- set global properties for this build -->
<property name= "src " value= ". "/>
<property name= "build " value= "classes "/>
<property name= "distribute " value= "dist "/>
<property name= "outFile " value= "Testant "/>
<property name= "lib " value= "./lib "/>
<property name= "mainClass.name " value= "testa.TestAnt "/>
<path id= "lib.path ">
<fileset dir= "${lib} ">
<include name= "**/*.jar "/>
</fileset>
</path>
<path id= "project.classpath ">
<pathelement location= "${build} "/>
</path>
<target name= "init ">
<!-- Create the time stamp -->
<tstamp/>
<!-- Create the build directory structure used by compile -->
<mkdir dir= "${build} "/>
</target>
<target name= "compile " depends= "init ">
<!-- Compile the java code from ${src} into ${build} -->
<javac srcdir= "${src} " destdir= "${build} " >
<classpath refid= "lib.path "/>
</javac>
</target>
<target name= "dist " depends= "compile ">
<!-- Create the distribution directory -->
<mkdir dir= "${distribute}/lib "/>
<!-- Put everything in ${build} into the output JAR file -->
<!-- Add a timestamp to the output filename as well -->
<jar jarfile= "${distribute}/lib/${outFile}-${DSTAMP}.jar " basedir= "${build} ">
<manifest>
<attribute name= "Main-Class " value= "${mainClass.name} "/>
</manifest>
<fileset dir= "${lib} ">
<include name= "**/*.jar "/>
</fileset>
</jar>
</target>
<target name= "clean ">
<!-- Delete the ${build} and ${distribute} directory trees -->
<delete dir= "${build} "/>
<delete dir= "${distribute} "/>
</target>
<target name= "building " depends= "compile " >