如何用ant解压和压缩文件

解压文件，然后替换了2个文件，然后压缩为文件（文件名中包含了日期）。

<?xml version="1.0" encoding="UTF-8"?>
<project name="unzip" default="auto-build" basedir=".">	
	 <tstamp>
	    <format property="TODAY" pattern="dd-MMM-yyyy" locale="us"/>
	</tstamp>	
	<target name="-check-exist">
	    <available property="file.exists" file="apache-archiva-1.4-M1"/>		
	</target>
	<target name="delete-file" depends="-check-exist" if="${file.exists}">
	    <delete file="apache-archiva-1.4-M1"/>
	    <echo>delete file...</echo>
	</target>
	<target name="auto-build" depends="delete-file">
		<unzip src="apache-archiva-1.4-M1-bin.zip" dest="." />
		<copy file="37870_thumb_logo.png" todir="apache-archiva-1.4-M1/apps/archiva/images"/>
		<delete file="apache-archiva-1.4-M1/conf/archiva.xml"/>
		<copy file="archiva.xml" todir="apache-archiva-1.4-M1/conf"/>
		<delete file="apache-archiva-1.4-M1/conf/jetty.xml"/>
		<copy file="jetty.xml" todir="apache-archiva-1.4-M1/conf"/>
		<zip basedir="apache-archiva-1.4-M1" destfile="apache-archiva-1.4-M1-${TODAY}.zip"/>
	</target>
</project>

运行结果：
E:\automatize>ant
Buildfile: E:\automatize\build.xml

-check-exist:

delete-file:

auto-build:
    [unzip] Expanding: E:\automatize\apache-archiva-1.4-M1-bin.zip into E:\autom
atize
     [copy] Copying 1 file to E:\automatize\apache-archiva-1.4-M1\apps\archiva\i
mages
   [delete] Deleting: E:\automatize\apache-archiva-1.4-M1\conf\archiva.xml
     [copy] Copying 1 file to E:\automatize\apache-archiva-1.4-M1\conf
   [delete] Deleting: E:\automatize\apache-archiva-1.4-M1\conf\jetty.xml
     [copy] Copying 1 file to E:\automatize\apache-archiva-1.4-M1\conf
      [zip] Building zip: E:\automatize\apache-archiva-1.4-M1-01-Nov-2011.zip

BUILD SUCCESSFUL
Total time: 6 seconds