To avoid resubmit of liferay action url

Problem: Click on an actionURL and action is successfully completed and page gets displayed on the browser. Click on refresh button again the same action gets called and performs the action again.
Resolution: set a tag value in liferay-portlet.xml
<action-url-redirect>true</action-url-redirect>
by default the value of this tag is false.
Note: it’s not a substitute to open another jsp page after completing the action.