Associating Grails Data with Map Commands

Grails 2.0.3 I had a problem with data binding to object commands. I have a jquery query similar to this HTTP: // local: 8080 / API / test.json callback = jQuery17102313091890902648_1334273415631 & ex [0] [a] = a0 & ex [0] [b] = b0 & ex [1] [a] = a1 & ex [? 1] [b] = b1

I need a way to bind data from the request url to the object command. Something like that

class TestCommand
{
    List<Map<String, String>> ex
    static constraints = {}
}

I wanted to bind the data dynamically so that I could get ex [0] .a = a0 and ex [0] .b = b0 and use it directly in the controller. This works great for a list. But not working for a list of cards. Is there a way to link data like this