IPN - get Item names for Add to Cart button

Normally we are getting item name, item number, quantity by using
request.getParameter("item_name");
request.getParameter("item_number");
request.getParameter("quantity");

But we can't do it for a Add to Cart button
it can be done by
First Item:
request.getParameter("item_name1");
request.getParameter("item_number1");
request.getParameter("quantity1");
Second Item:
request.getParameter("item_name2");
request.getParameter("item_number2");
request.getParameter("quantity2");