SimplePortlet.java

public class SimplePortlet extends GenericPortlet {
  public void render(RenderRequest request, RenderResponse response) throws PortletException, IOException {
		String page = request.getParameter("page");

		PortletContext portletContext = getPortletContext();
		PortletRequestDispatcher portletRequestDispatcher = null;

		if(page == null){
			portletRequestDispatcher = portletContext.getRequestDispatcher("/WEB-INF/my-portlet-folder/view.jsp");
		}

		if(page.equals("page-1")){
			portletRequestDispatcher = portletContext.getRequestDispatcher("/WEB-INF/my-portlet-folder/view-1.jsp");
		}

		if(page.equals("page-2")){
			portletRequestDispatcher = portletContext.getRequestDispatcher("/WEB-INF/my-portlet-folder/view-2.jsp");
		}

		portletRequestDispatcher.include(request, response);
	}
}