how to change xml path dynamically

<servlet>
        <servlet-name>JobCreateServlet</servlet-name>
        <servlet-class>com.vayam.gip.JobCreateServlet</servlet-class>
        <init-param>
            <param-name>upload_path</param-name>
            <param-value>/home/gip/static</param-value>
        </init-param>
    </servlet>

above code is web.xml code. I want to change param-valu. i.e. /home/gip/static to /home/ToUser'sFolder. I mean how can change the path dynamically?