jsp隐式对象

Implicit Objects

The JSP expression language defines a set of implicit objects:

pageContext

:
The context for the JSP page. Provides access to various objects including:

servletContext

:
The context for the JSP page’s servlet and any web components contained in the same application. See Accessing the Web Context.

session

:
The session object for the client. See Maintaining Client State.

request

:
The request triggering the execution of the JSP page. See Getting
Information from Requests.

response

:
The response returned by the JSP page. See Constructing Responses.

In addition, several implicit objects are available that allow easy access to the following objects:

param

:
Maps a request parameter name to a single value

paramValues

:
Maps a request parameter name to an array of values

header

:
Maps a request header name to a single value

headerValues

:
Maps a request header name to an array of values

cookie

:
Maps a cookie name to a single cookie

initParam

:
Maps a context initialization parameter name to a single value

Finally, there are objects that allow access to the various scoped variables described in Using Scope Objects.

pageScope

:
Maps page-scoped variable names to their values

requestScope

:
Maps request-scoped variable names to their values

sessionScope

:
Maps session-scoped variable names to their values

applicationScope

:
Maps application-scoped variable names to their values