JSP 2.0 Expression Language - Implicit Objects

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
foo =

EL Expression Result ${param.foo} bar ${param["foo"]} bar ${header["host"]} psesda.hoyu.edu.hk:82 ${header["accept"]} */* ${header["user-agent"]} Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)

EL Expression	Result
${param.foo}	bar
${param["foo"]}	bar
${header["host"]}	psesda.hoyu.edu.hk:82
${header["accept"]}	/
${header["user-agent"]}	Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)