Writing to a properties file with Ant

I find this useful when I want to change how the application works depending on where and why it is being deployed. This blog post assumes you have Ant installed!

In the build.xml file;

<!-- Add the property file -->

<property file="project.properties"/>

<!--  Write a property to the file with a value based on the target -->

<target name="liveExample">

     <echo message="This target example has the live properties"/>

     <propertyfile

          file="project.properties"

          comment="Setting important system procedure variable to 100">

          <entry key="importantVariable" value="100"/>

          </propertyfile>

</target>

<target name="testExample">

     <echo message="This target example has the test properties"/>

     <propertyfile

          file="project.properties"

          comment="Setting important system procedure variable to 10 for testing purposes">

          <entry key="importantVariable" value="10"/>

          </propertyfile>

</target>

How it works

The properties file (project.properties) has a key/value pair written to it. Based on what target is run, the key has a different value. This allows us to control how the application works based on how we deploy it. For further reading on Ant's PropertyFile task see their manual.