Difference between getAttribute() and getParameter()

Generally, a parameter is a string value that is most commonly known for being sent from the client to the server (e.g. a form post) and retrieved from the servlet request. The frustrating exception to this is ServletContext initial parameters which are string parameters that are configured in web.xml and exist on the server.

An attribute is a server variable that exists within a specified scope i.e.:

• application, available for the life of the entire application
• session, available for the life of the session
• request, only available for the life of the request
• page (JSP only), available for the current JSP page only

• getParameter() returns http request parameters. Those passed from the client to the server. For example http://example.com/servlet?parameter=1. Can only return String

• getAttribute() is for server-side usage only - you fill the request with attributes that you can use within the same request. For example - you set an attribute in a servlet, and read it from a JSP. Can be used for any object, not just string.