I need some information regarding usage of variables in web.xml

For example i have the following entry in web.ml

    <env-entry id="taskTime">

I would like to use a variable in web.xml and read the value from properties file.
like i would like to specify as


and define TASK_START_TIME = 3322332 in some application.properties file.

The value should be replaced either during build/deployment time.
Can anybody give pointer to the above requirement.