如果蚂蚁else条件？ [英] Ant if else condition?

问题描述

是否有一个if / else条件，我可以用一个Ant任务？

Is there an if/else condition that I can use for an Ant task?

这是我至今写：

<target name="prepare-copy" description="copy file based on condition">
        <echo>Get file based on condition</echo>
    <copy file="${some.dir}/true" todir="."  if="true"/>
</target>

脚本，如果条件为真，将上面复制的文件。如果条件为假，我要复制另一个文件？这有可能在蚂蚁？

The script above will copy the file if a condition is true. What if the condition is false and I wish to copy another file? Is that possible in Ant?

我可以一个参数传递给上述任务，确保公司顺利通过参数是

I could pass a param to the above task and make sure the param that's passed is

推荐答案

的如果属性不存在对＆LT;复制＆GT; 。它应该被应用到＆lt;目标方式＆gt;

The if attribute does not exist for <copy>. It should be applied to the <target>.

下面是如何使用的为例取决于目标的属性和的 如果和除非属性来控制的依赖的目标执行。只有两个中的一个应该执行。

Below is an example of how you can use the depends attribute of a target and the if and unless attributes to control execution of dependent targets. Only one of the two should execute.

<target name="prepare-copy" description="copy file based on condition"
    depends="prepare-copy-true, prepare-copy-false">
</target>

<target name="prepare-copy-true" description="copy file based on condition"
    if="copy-condition">
    <echo>Get file based on condition being true</echo>
    <copy file="${some.dir}/true" todir="." />
</target>

<target name="prepare-copy-false" description="copy file based on false condition" 
    unless="copy-condition">
    <echo>Get file based on condition being false</echo>
    <copy file="${some.dir}/false" todir="." />
</target>

如果您正在使用ANT 1.8+，那么你可以使用属性扩展，它会评估属性的值来确定布尔值。所以，你可以使用如果=$ {复制条件}而不是如果=复制条件

If you are using ANT 1.8+, then you can use property expansion and it will evaluate the value of the property to determine the boolean value. So, you could use if="${copy-condition}" instead of if="copy-condition".

和蚂蚁1.7.1早些时候，指定属性的名称。如果定义了属性，并具有任何价值（甚至一个空字符串），那么它的值为true。

In ANT 1.7.1 and earlier, you specify the name of the property. If the property is defined and has any value (even an empty string), then it will evaluate to true.

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