jsf in action 笔记:潜藏对象(Implicit Variables)--2008.04.09

2008.04.09 摘自 JSF in action 2.4.2 Using implicit variables   Page/115

Table 2.6 The JSF EL supports implicit variables for accessing commonly used objects. Most of the
same variables are supported by the JSP 2.0 EL.

Implicit variable	Description	Example	Supported in JSP 2.0 EL?
applicationScope	A Map of application-scoped variables, keyed by name.	#{application- Scope.myVariable}	Yes
cookie	A Map of cookie values for the current requested, keyed by cookie name.	#{cookie.myCookie}	Yes
facesContext	The FacesContext instance for the current request.	#{facesContext}	No
header	A Map of the HTTP header values for the current request, keyed by header name. If there are multiple values for the given header name, only the first is returned.	#{header['User-Agent']}	Yes
headerValues	A Map of the HTTP header values for the current request, keyed by header name. For each key, an array of Strings is returned (so that all values can be accessed).	#{headerValues['Accept- Encoding'][3]}	Yes
initParam	A Map of the application initialization parameters, keyed by parameter name. (These are also known as servlet context initialization parameters, and are set in the deployment descriptor).	#{initParam.adminEmail}	Yes
param	A Map of the request parameters, keyed by header name. If there are multiple values for the given parameter name, only the first is returned.	#{param.address}	Yes
paramValues	A Map of the request parameters, keyed by header name. For each key, an array of Strings is returned (so that all values can be accessed).	#{param.address[2]}	Yes
requestScope	A Map of request scoped variables, keyed by name.	#{requestScope.user- Preferences}	Yes
sessionScope	A Map of session scoped variables, keyed by name.	#{sessionScope['user']}	Yes
view	The current view.	#{view.locale}	No