How to set colspan and rowspan in JSF panelGrid?

How can I set colspan and rowspan in JSF <h:panelGrid>?

None of both is possible with the standard JSF implementation. There are 3 ways to fix this:

1. Write plain HTML yourself. A <h:panelGrid> basically renders a HTML <table>. Do the same.
2. Create a custom HTML renderer which supports this. It'll however be a lot of sweat and pain.
3. Use a 3rd party component library which supports this.
   • Tomahawk has a <t:panelGroup> component which supports colspan in <h:panelGrid>.
   • RichFaces (3.x only) has a <rich:column> component which supports both colspan and rowspan in <rich:dataTable>.
   • PrimeFaces has a <p:row> next to <p:column> which is supported in both <p:panelGrid> and <p:dataTable> (also with <p:columnGroup>).

Since 24 januari 2012 Primefaces also has the possibility to use colspan and rowspan in the panelGrid component of Primefaces. See:

http://www.primefaces.org/showcase/ui/panel/panelGrid.xhtml

Use: rich:column colspan="2" of RichFaces

<rich:column colspan="2">                        
<h:outputText  value="Ingrese el texto de la imagen" /> 
</rich:column>  

Assume

1. a message resource file with two entries:

   key.row=</td></tr><tr><td
   key.gt=>

2. row.xhtml

   <ui:composition 
       xmlns="http://www.w3.org/1999/xhtml"
       xmlns:ui="http://java.sun.com/jsf/facelets"
       xmlns:h="http://java.sun.com/jsf/html"
       xmlns:f="http://java.sun.com/jsf/core"
       xmlns:c="http://java.sun.com/jsp/jstl/core" >
   
       <c:forEach begin="0" end="#{colspan-2}">
           <h:panelGroup />
       </c:forEach>
   
       <h:panelGroup>
         <h:outputText value="#{i18n['key.row']}" escape="false" />
         <h:outputText value=" colspan='#{colspan}' #{cellAttributes}" />
         <h:outputText value="#{i18n['key.gt']}" escape="false" />
   
         <ui:insert />
       </h:panelGroup>
   
   </ui:composition>
   

   then, for example

   <h:panelGrid columns="3">
     <h:outputText value="r1-c1" />
     <h:outputText value="r1-c2" />
     <h:outputText value="r1-c3" />
   
     <ui:decorate template="/row.xhtml">
       <ui:param name="colspan" value="3" />
       <ui:param name="cellAttributes" value=" align='center'" />
   
       <div>Hello!!!!!</div>
     </ui:decorate>
   

Prints a table with 3 rows:

1. r1-c1, r1-c2 , r1-c3

2. 3 blank cells

3. a cell aligned center, having colspan 3 and containing a hello div.

I agree with BalusC's answer and want to add, that the Primefaces JSF2 component library also offers this functionality if you use its p:dataTable component. It is called grouping there.