How to generate a dynamic URL using <dsp:a> in Oracle Commerce(ATG)

Question

I'm trying to display list of products in a jsp using ProductLookup droplet as shown below. I'm also trying to give a hyperlink to navigate to product details page of the individual product.

<dsp:droplet name="/atg/commerce/catalog/ProductLookup">
    <dsp:param param="element.id" name="id"/>
    <dsp:oparam name="output"><br/>
    <dsp:a href="display_product.jsp?itemId=${id}">  
    Product display Name: 
    <b><dsp:valueof param="element.displayName"/></b><br/>
    Product description Name:
    <dsp:valueof param="element.description"/>
    </dsp:a>
    </dsp:oparam>
</dsp:droplet>

However, I'm facing issue while passing the id of the product to href tag of dsp:a. The resultant HTML has hardcoded ${id} as display_product.jsp?itemId=${id}. I'm getting list of products, but the URL is where I'm facing issue. How do I pass the value in element.id into the href attribute of dsp:a?

I've also tried the following, but no success.

1.

<dsp:a href="display_product.jsp?itemId=<%=out.print(element.id) %>">

2.

<dsp:a href="display_product.jsp?itemId=<%=out.print(id) %>">

3.

<dsp:getvalueof var="id" id="id" >
            <dsp:a href="display_product.jsp?itemId=${id}">
            Product display Name: 
            <b><dsp:valueof param="element.displayName"/></b><br/>
            Product description Name:
            <dsp:valueof param="element.description"/>
            </dsp:a>
            </dsp:getvalueof>

Answer 1

To pass parameters to another page you simply use the <dsp:param> tag as per the code fragment below (nested within your ProductLookup droplet):

This is the old-school ATG approach:

 <dsp:a href="display_product.jsp">
     Product Name: <b><dsp:valueof param="element.displayName"/></b><br/>
     Product description: <dsp:valueof param="element.description"/>
     <%-- this will pass the itemId parameter and value--%>
     <dsp:param name="itemId" param="element.id"/>
 </dsp:a>

The preferred approach is to use jstl EL variables which makes your jsp's cleaner and easier to read, as well as allowing more flexibility when referring to the values:

<%-- name the "element" and convert to a map  --%>
<dsp:tomap var="product" param="element" recursive="false"/>
<dsp:a href="display_product.jsp">
     Product Name: <b>${ product.displayName }</b><br/>
     Product description: ${ product.description }
     <dsp:param name="itemId" value="${ product.id }"/>
</dsp:a>

I have used recursive="false" in the above example because you are only referencing to direct properties of a product. If you wanted to refer to properties of properties then you could do something like this (the code below is not tested but should give you the general idea):

<dsp:tomap var="product" param="element" recursive="true"/>
<dsp:img page="${ product.image.url }">

UPDATE:

As I continue to be amazed how few people understand how to do even the most basic thing such as passing parameter, I have included other DSP tags which can be used in conjunction with the <dsp:param>

You can pass parameters for included JSP fragments which use the <dsp:include>

<dsp:tomap var="product" param="element" recursive="false"/>
<dsp:include page="fragments/myfragment.jsp">
    <dsp:param name="itemId" value="${ product.id } />
</dsp:include>

This approach will work for these tags as well:

• <dsp:iframe>
• <dsp:img>
• <dsp:link>