1.To get currentURL :
b.For actionURL:
3.Using TLD's in Liferay : a. renderURL
PortletURL url = PortletURLUtil.getCurrent(renderRequest, renderResponse);
2. Creating PortletURL from renderResponse :
a.For renderURL:PortletURL renderURL = renderResponse.createRenderURL();
b.For actionURL:
PortletURL actionURL = renderResponse.createActionURL();
c. For resourceURL
ResourceURL addChannelURL = renderResponse.createResourceURL();
addChannelURL.setResourceID(RESOURCEURL_ID);
addChannelURL.setParameter(RESOURCEURL_PARAM, currentSourceGuid);
3.Using TLD's in Liferay : a. renderURL
<portlet:renderURL windowState="<%= WindowState.ur_state.toString() %>">
<portlet:param name="param_name" value="param_value" />
<portlet:param name="param_name" value="param_value" />
</portlet:renderURL>
b. actionURL<portlet:actionURL windowState="<%= WindowState.ur_state.toString() %>">
<portlet:param name="param_name" value="param_value" />
<portlet:param name="param_name" value="param_value" />
</portlet:actionURL>
c. resourceURL
<portlet:resourceURL">
<portlet:param name="param_name" value="param_value" />
<portlet:param name="param_name" value="param_value" />
</portlet:resourceURL>