How to check if a property exists?
问题 How do I check the existence of a property using Ant? I am open to the use of ant-contrib , if Ant doesn't provide a similar thing. Also, ant-contrib has an assert task, which provides exists , but the assertion is not what I need here since I would prefer a boolean return value. 回答1: You can use the Condition task with an isset condition. <project default="test"> <property name="a" value="a"/> <target name="test"> <condition property="a.set" else="false"> <isset property="a"/> </condition>