Java 蚂蚁过滤 - 如果未设置属性则失败
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ant filtering - fail if property not set
提问by James Cooper
I've got a ant build.xmlthat uses the <copy>task to copy a variety of xml files. It uses filtering to merge in properties from a build.propertiesfile. Each environment (dev, stage, prod) has a different build.propertiesthat stores configuration for that environment.
我有一只蚂蚁build.xml，它使用该<copy>任务复制各种 xml 文件。它使用过滤来合并build.properties文件中的属性。每个环境（dev、stage、prod）都有一个不同的build.properties环境来存储该环境的配置。
Sometimes we add new properties to the Spring XML or other config files that requires updating the build.propertiesfile.
有时我们会向 Spring XML 或其他需要更新build.properties文件的配置文件添加新属性。
I want ant to fail fast if there are properties missing from build.properties. That is, if any raw @...@tokens make it into the generated files, I want the build to die so that the user knows they need to add one or more properties to their local build.properties.
如果 .git 缺少属性，我希望蚂蚁快速失败build.properties。也就是说，如果任何原始@...@令牌进入生成的文件，我希望构建终止，以便用户知道他们需要向其本地 build.properties 添加一个或多个属性。
Is this possible with the built in tasks? I couldn't find anything in the docs. I'm about to write a custom ant task, but maybe I can spare myself the effort.
这可以通过内置任务实现吗？我在文档中找不到任何内容。我即将编写一个自定义的 ant 任务，但也许我可以省点力气。
Thanks
谢谢
采纳答案by Jason Day
You can do it in ant 1.7, using a combination of the LoadFiletask and the matchcondition.
您可以在 ant 1.7 中使用LoadFile任务和match条件的组合来完成。
<loadfile property="all-build-properties" srcFile="build.properties"/>
<condition property="missing-properties">
<matches pattern="@[^@]*@" string="${all-build-properties}"/>
</condition>
<fail message="Some properties not set!" if="missing-properties"/>
回答by matt b
I was going to suggest that you attempt to use <property file="${filter.file}" prefix="filter">to actually load the properties into Ant, and then failif any of them are not set, but I think I was interpreting your problem wrong (that you wanted to fail if a specified property was not set in the properties file).
我打算建议您尝试使用<property file="${filter.file}" prefix="filter">将属性实际加载到 Ant 中，然后fail如果其中任何一个未设置，但我认为我对您的问题的解释是错误的（如果未设置指定的属性，您希望失败在属性文件中）。
I think your best bet might be to use <exec>to (depending on your dev platform) do a grep for the "@" character, and then set a property to the number of occurences found. Not sure of exact syntax but...
我认为您最好的选择可能是使用<exec>（取决于您的开发平台）对“@”字符执行 grep，然后将属性设置为找到的出现次数。不确定确切的语法，但是...
<exec command="grep \"@\" ${build.dir} | wc -l" outputproperty="token.count"/>
<condition property="token.found">
<not>
<equals arg1="${token.count}" arg2="0"/>
</not>
</condition>
<fail if="token.found" message="Found token @ in files"/>
回答by matt b
if exec command is deprecated in your version of ant you can use redirectors, something like:
如果 exec 命令在您的 ant 版本中被弃用，您可以使用重定向器，例如：
<exec executable="grep">
<arg line="@ ${build.dir}"/>
<redirector outputproperty="grep.out"/>
</exec>
<exec executable="wc" inputstring="${grep.out}">
<arg line="-l"/>
<redirector outputproperty="token.found"/>
</exec>
to create the token.found property
创建 token.found 属性
<condition property="token.found">
<not>
<equals arg1="${token.count}" arg2="0"/>
</not>
</condition>
<fail if="token.found" message="Found token @ in files"/>
for the conditonal
对于有条件的
回答by dovetalk
If you are looking for a specific property, you can just use the fail task with the unless attribute, e.g.:
如果你正在寻找一个特定的属性，你可以使用带有除非属性的失败任务，例如：
<fail unless="my.property">Computer says no. You forgot to set 'my.property'!</fail>
<fail unless="my.property">Computer says no. You forgot to set 'my.property'!</fail>
Refer to the documentation for Ant's fail taskfor more detail.
有关更多详细信息，请参阅Ant 的失败任务的文档。
回答by Vadzim
Since Ant 1.6.2 conditioncan also be nested inside fail.
由于 Ant 1.6.2condition也可以嵌套在fail.
The following macro makes it easy to conditionally check multiple properties.
以下宏可以轻松地有条件地检查多个属性。
<macrodef name="required-property">
<attribute name="name"/>
<attribute name="prop" default="@{name}"/>
<attribute name="if" default="___"/>
<attribute name="unless" default="___"/>
<sequential>
<fail message="You must set property '@{name}'">
<condition>
<and>
<not><isset property="@{prop}"/></not>
<or>
<equals arg1="@{if}" arg2="___"/>
<isset property="@{if}"/>
</or>
<or>
<equals arg1="@{unless}" arg2="___"/>
<not><isset property="@{unless}"/></not>
</or>
</and>
</condition>
</fail>
</sequential>
</macrodef>
<target name="required-property.test">
<property name="prop" value=""/>
<property name="cond" value="set"/>
<required-property name="prop"/>
<required-property name="prop" if="cond"/>
<required-property name="prop" unless="cond"/>
<required-property name="prop" if="cond2"/>
<required-property name="prop" unless="cond2"/>
<required-property name="prop" if="cond" unless="cond"/>
<required-property name="prop" if="cond" unless="cond2"/>
<required-property name="prop" if="cond2" unless="cond"/>
<required-property name="prop" if="cond2" unless="cond2"/>
<required-property name="prop2" unless="cond"/>
<required-property name="prop2" if="cond2"/>
<required-property name="prop2" if="cond2" unless="cond"/>
<required-property name="prop2" if="cond" unless="cond"/>
<required-property name="prop2" if="cond2" unless="cond2"/>
<required-property name="success"/>
</target>
