JSP implicit object

Type

Typical use by the scriptlet writer

pageContext

javax.servlet.jsp.PageContext

Barely in use. This is more of a backbone

object used by the servlet that was autogenerated

from the servlet code. We will

discuss the autogenerated servlet later in

this chapter.

request

javax.servlet.http.HttpServletRequest

Queries request information; for example,

queries form parameters, inbound cookies,

request headers, etc.

response

javax.servlet.http.HttpServletResponse

Manipulates the response; for example,

add cookies, redirect, etc.

session

javax.servlet.http.HttpSession

Accesses the session state information

associated with the request. For example,

get/set session attributes or invalidate the

session.

config

javax.servlet.ServletConfig

Obtains configuration parameters for this

page.

application

javax.servlet.ServletContext

Obtains configuration parameters for this

application and uses its utility method (for

example, log()).

out

javax.servlet.jsp.JspWriter

Writes data into the page and manipulates

the output buffer used by JSP.

page

java.lang.Object

Represents the Java this variable for the

current page invocation.

exception

java.lang.Exception

In error pages only (see more on error

pages in the upcoming sections), represents

the exception that triggered the error

page.