Access Get parameter with a scriptlet

问题

I hava a url such as search.do?offset=20

offset sometimes is in the url sometimes not. When it is not in the URL i want it to be 0.

i try, without success, to retrieve the value with a scriptlet as follows:

<%  Integer offset = (pageContext.findAttribute("offset")==null) ? new Integer("0") : new Integer((String) pageContext.findAttribute("offset")); %>

Anyone knows what i am doing wrong?

回答1:

You should use this instead.

<% Integer offset = request.getParameter("offset") != null && request.getParameter("offset").length() > 0 ? new Integer(request.getParameter("offset")) : new Integer(0); %>

Be careful because if "offset" parameter has an incorrect integer representation a NumberFormatException will be thrown.

This is basic JSP. You could use Struts or other J2EE framework that make these conversions safer for you.

来源：https://stackoverflow.com/questions/280714/access-get-parameter-with-a-scriptlet