Expression-Language Implicit Objects (EL表达式隐式对象)

Expression-Language 

 

Implicit Object	Description
applicationScope	This is a Map that contains all application-scoped variables. The Map is keyed on the name of the variable.
cookie	This is a Map that maps cookie names to a single Cookie object.If more thatn one cookie exists for a given name, the first of these cookies is used for that name.
header	This is a Map that contains the values of each header name.
headerValues	This is a Map that maps a header name to a string array of all the possible values for that header.
initParam	This is a Map that maps context initialization parameter names to their string parameter values.
pageContext	The PageContext object.
pageScope	This is a Map that contains all page-scoped variables. The Map is keyed on the Name of the variable.
param	This is a Map that contains the names of the parameters to a page. Each parameter name is mapped to a single string value.
paramValues	This is a Map that maps a parameter name to a string array of all the values for that parameter.
requestScope	This is a Map that contains all request-scoped variables. The Map is keyed on the name of the variable.
sessionScope	This is a Map that contains all session-scoped variables. The Map is keyed on the name of the variable.