JSP表达式语言

 看其本身自带的例子

1，

EL Expression	Result
${1}	1
${1 + 2}	3
${1.2 + 2.3}	3.5
${1.2E4 + 1.4}	12001.4
${-4 - 2}	-6
${21 * 2}	42
${3/4}	0.75
${3 div 4}	0.75
${3/0}	Infinity
${10%4}	2
${10 mod 4}	2
${(1==2) ? 3 : 4}	4

2，

EL Expression	Result
${1 < 2}	true
${1 lt 2}	true
${1 > (4/2)}	false
${1 > (4/2)}	false
${4.0 >= 3}	true
${4.0 ge 3}	true
${4 <= 3}	false
${4 le 3}	false
${100.0 == 100}	true
${100.0 eq 100}	true
${(10*10) != 100}	false
${(10*10) ne 100}	false

3，

EL Expression	Result
${'a' < 'b'}	true
${'hip' > 'hit'}	false
${'4' > 3}	true

4，

EL Expression	Result
${param.foo}	bar
${param["foo"]}	bar
${header["host"]}	127.0.0.1:8080
${header["accept"]}	*/*
${header["user-agent"]}	Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; Maxthon; .NET CLR 2.0.50727)

5,

EL Expression	Result
${param["foo"]}	0.2
${my:reverse(param["foo"])}	2.0
${my:reverse(my:reverse(param["foo"]))}	0.2
${my:countVowels(param["foo"])}	0