What is the difference between getAttribute() and getParameter() of jsp?

getParameter is used to extract the values contained in the client request.

http://getParameter.com/hellp?name=1

getAttribute is the value set on the server that can be used within the same request. It is used to refine and deliver values to be delivered to the view, such as the controller servlet.

// in servlet 
request.setAttribute("user_vector", Arrays.asList(3, 4, 2, 1));

// // in jsp
Object vector = request.getAttribute("user_vector");