This example illustrates some of the implicit objects available
in the Expression Language. The following implicit objects are
available (not all illustrated here):
pageContext - the PageContext object
pageScope - a Map that maps page-scoped attribute names to
their values
requestScope - a Map that maps request-scoped attribute names
to their values
sessionScope - a Map that maps session-scoped attribute names
to their values
applicationScope - a Map that maps application-scoped attribute
names to their values
param - a Map that maps parameter names to a single String
parameter value
paramValues - a Map that maps parameter names to a String[] of
all values for that parameter
header - a Map that maps header names to a single String
header value
headerValues - a Map that maps header names to a String[] of
all values for that header
initParam - a Map that maps context initialization parameter
names to their String parameter value
cookie - a Map that maps cookie names to a single Cookie object.
Change Parameter
EL Expression
Result
${param.foo}
bar
${param["foo"]}
bar
${header["host"]}
57918.icu
${header["accept"]}
*/*
${header["user-agent"]}
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