Ant 中属性文件中的变量 [英] Variables from properties file in Ant

问题描述

我有一个 Android 应用，需要针对不同的环境(例如 UAT、暂存、生产等)构建.每个环境都需要不同的属性(例如，网址、包等).

I have an Android app that needs to be built for different environments (e.g., UAT, staging, production, etc.). Each environment needs different properties (e.g., URLs, packages, etc.).

我想将所有不同的参数放在一个属性文件中，并在每个参数前面加上它匹配的环境.

I would like to put all the different parameters into a single properties file and prefix each parameter with the environment it matches to.

例如，属性文件将包含用于开发环境的 dev.home-url = http://home_dev.com 和 prod.home-url = http://home.com 用于生产环境.

For example, the properties file will contain dev.home-url = http://home_dev.com for the development environment and prod.home-url = http://home.com for the production environment.

我使用下面的代码创建一个属性，该属性指向带有 params 前缀的属性文件:

I use the below to create a property that points to the properties file with a prefix of params:

<property file="parameters.properties" prefix="params" />

为了使用属性，我使用:

And to use a property, I use:

${params.home-url}

当我需要将环境的前缀添加到参数时，问题就来了.它最终看起来像这样，这显然是不可能的:

The problem comes when I need to add the prefix of the environment to the parameter. It would end up looking like this, which obviously can't be done:

${params.${env-prefix}.home-url}

推荐答案

关于 Ant 的一个常见问题是:

A frequently asked question about Ant is:

我该怎么做<property name="prop"value="${${anotherprop}}"/>(双重扩展属性)?

How can I do something like <property name="prop" value="${${anotherprop}}"/> (double expanding the property)?

以下 Ant 构建文件的灵感来自该常见问题解答.

The following Ant build file was inspired by that FAQ.

parameters.properties

dev.home-url = http://home_dev.com
prod.home-url = http://home.com

build.xml

<project default="example">
    <property name="env-prefix" value="dev" />
    <property file="parameters.properties" prefix="params" />

    <macrodef name="propertycopy">
        <attribute name="name" />
        <attribute name="from" />
        <sequential>
            <property name="@{name}" value="${@{from}}" />
        </sequential>
    </macrodef>

    <target name="example">
        <propertycopy name="local.property" from="params.${env-prefix}.home-url" />
        <echo>${local.property}</echo>
    </target>
</project>

执行 example 任务输出:

Buildfile: /workspace/build.xml
example:
     [echo] http://home_dev.com
BUILD SUCCESSFUL
Total time: 405 milliseconds

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