Head First Servlets and JSP, 2nd Edition

Examples using pageContext to get and set attributes

Setting a page-scoped attribute

<% Float one = new Float(42.5); %>
<% pageContext.setAttribute("foo", one); %>

Note

pageContext getAttribute(String) is for page scope

There are TWO overloaded getAttribute() methods you can call on pageContext: a one-arg that takes a String, and a two-arg that takes a String and an int. The one-arg version works just like all the others—it’s for attributes bound TO the pageContext object. But the two-arg version can be used to get an attribute from ANY of the four scopes.

Getting a page-scoped attribute

<%= pageContext.getAttribute("foo") %>

Using the pageContext to set a session-scoped attribute

<% Float two = new Float(22.4); %>
<% pageContext.setAttribute("foo", two, PageContext.SESSION_SCOPE); %>

Using the pageContext to get a session-scoped attribute

<%= pageContext.getAttribute("foo", PageContext.SESSION_SCOPE) %>
(Which is identical to: <%= session.getAttribute("foo") %> )

Using the pageContext to get an application-scoped attribute

Email is:
<%= pageContext.getAttribute("mail", PageContext.APPLICATION_SCOPE) %>

Within a JSP, the code above is identical to:

Email is:
<%= application.getAttribute("mail") %>

Using the pageContext to find an attribute when you don’t know the scope

<%= pageContext.findAttribute("foo") %>

Note

find it where?

Where does the findAttribute() method look? It looks first in the page context, so if there’s a “foo” attribute with page context scope, then calling findAttribute(String name) ...