我正在使用ANT将我的东西部署到Tomcat。但是我在缺少依赖项方面遇到了麻烦，我想添加Ivy，因为它被推荐了。

现在，我将其添加到build.xml文件中：

<!-- Ivy settings start-->

    <condition property="ivy.home" value="${env.IVY_HOME}">
        <isset property="env.IVY_HOME" />
    </condition>


    <target name="download-ivy" unless="offline" description="Download Ivy">
        <mkdir dir="${ivy.jar.dir}"/>
            <!-- download Ivy from web site so that it can be used even without any special installation -->
        <get src="http://repo2.maven.org/maven2/org/apache/ivy/ivy/${ivy.install.version}/ivy-${ivy.install.version}.jar" 
            dest="${ivy.jar.file}" usetimestamp="true"/>
    </target>


    <target name="init-ivy" depends="download-ivy" description="Initialize Ivy">
        <!-- try to load ivy here from ivy home, in case the user has not already dropped
        it into ant's lib dir (note that the latter copy will always take precedence).
        We will not fail as long as local lib dir exists (it may be empty) and
        ivy is in at least one of ant's lib dir or the local lib dir. -->
        <path id="ivy.lib.path">
            <fileset dir="${ivy.jar.dir}" includes="*.jar"/>
        </path>
        <taskdef resource="org/apache/ivy/ant/antlib.xml"
        uri="antlib:org.apache.ivy.ant" classpathref="ivy.lib.path"/>
    </target>

    <target name="update" depends="init-ivy" description="Download project dependencies">
        <!-- edited for brevity -->

        <ivy:retrieve pattern="lib/[conf]/[artifact]-[revision].[ext]" />
        <!-- edited for brevity -->
    </target>


    <target name="clean-all" depends="clean" description="Purge ivy cache">
        <ivy:cleancache/>
    </target>

<!-- Ivy settings end-->

这是我的ivy.xml：

<ivy-module version="2.0">
    <info organisation="org.apache" module="hello-ivy"/>
    <dependencies>
        <dependency org="commons-lang" name="commons-lang" rev="2.1"/>
    </dependencies>
</ivy-module>

这是我的日志：

Buildfile: C:\Users\Jansu\workspace\HelloWorld\build.xml
download-ivy:
      [get] Getting: http://repo2.maven.org/maven2/org/apache/ivy/ivy/2.2.0/ivy-2.2.0.jar
      [get] To: C:\Users\Jansu\.ant\lib\ivy-2.2.0.jar
      [get] Not modified - so not downloaded
init-ivy:
update:
[ivy:retrieve] :: Ivy 2.2.0 - 20100923230623 :: http://ant.apache.org/ivy/ ::
[ivy:retrieve] :: loading settings :: url = jar:file:/C:/Users/Jansu/.ant/lib/ivy-2.2.0.jar!/org/apache/ivy/core/settings/ivysettings.xml
[ivy:retrieve] :: resolving dependencies :: org.apache#hello-ivy;working@Jansu-PC
[ivy:retrieve]  confs: [default]
[ivy:retrieve]  found commons-lang#commons-lang;2.1 in public
[ivy:retrieve] downloading http://repo1.maven.org/maven2/commons-lang/commons-lang/2.1/commons-lang-2.1.jar ...
[ivy:retrieve] ................................................................................................................................................................................................................................................................................................................................................................................................................. (202kB)
[ivy:retrieve] .. (0kB)
[ivy:retrieve]  [SUCCESSFUL ] commons-lang#commons-lang;2.1!commons-lang.jar (1704ms)
[ivy:retrieve] downloading http://repo1.maven.org/maven2/commons-lang/commons-lang/2.1/commons-lang-2.1-sources.jar ...
[ivy:retrieve] ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ (255kB)
[ivy:retrieve] .. (0kB)
[ivy:retrieve]  [SUCCESSFUL ] commons-lang#commons-lang;2.1!commons-lang.jar(source) (1819ms)
[ivy:retrieve] downloading http://repo1.maven.org/maven2/commons-lang/commons-lang/2.1/commons-lang-2.1-javadoc.jar ...
[ivy:retrieve] .........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
[ivy:retrieve] ................................................................................................................................................................................................................................................................ (518kB)
[ivy:retrieve] .. (0kB)
[ivy:retrieve]  [SUCCESSFUL ] commons-lang#commons-lang;2.1!commons-lang.jar(javadoc) (2817ms)
[ivy:retrieve] :: resolution report :: resolve 2094ms :: artifacts dl 6357ms
    ---------------------------------------------------------------------
    |                  |            modules            ||   artifacts   |
    |       conf       | number| search|dwnlded|evicted|| number|dwnlded|
    ---------------------------------------------------------------------
    |      default     |   1   |   1   |   1   |   0   ||   3   |   3   |
    ---------------------------------------------------------------------
[ivy:retrieve] :: retrieving :: org.apache#hello-ivy
[ivy:retrieve]  confs: [default]

这是错误：

BUILD FAILED
    C:\Users\Jansu\workspace\HelloWorld\build.xml:177: impossible to ivy retrieve: java.lang.RuntimeException: problem during retrieve of org.apache#hello-ivy: java.lang.RuntimeException: Multiple artifacts of the module commons-lang#commons-lang;2.1 are retrieved to the same file! Update the retrieve pattern  to fix this error.

    Total time: 11 seconds

看来错误来自这种模式？：

<ivy:retrieve pattern="lib/[conf]/[artifact]-[revision].[ext]" />

但这对我来说似乎很牢固。

有什么建议？