jsp中C标签的表达式

jstl if 中不等于符号为：baine ！=

el表达式的取值du默认顺序:
pageScope requestScope sessionScope applicationScope

结构，采用.导航，也称为存取器 ${user.name} ${user.class.name}
输出daomap ${mapValue.key1}
输出数组 ${strArray[1]}
输出list ${list[1].name}

el表达式的运算
${1+2}= 3
${10/5}= 2.0
${10%3}= 1
${10 div 2}= 5.0
${10 mod 4}= 2

el表达式对应的运算符
等于 == eq
不等于 != ne
大于 > gt
小于 < lt
大于等于 >= ge
小于等于 <= le
与 && or
或 || and
非 ! not
加 +
减 -
乘 *
除以 / div
求莫 % mod

el表达式判断是否为空
request.setAttribute("value1",null) ${empty requestScope.value1} = true
request.setAttribute("value2","") ${empty requestScope.value1} = true
request.setAttribute("value3",new ArrayList()) ${empty requestScope.value1} = true
request.setAttribute("value4","i love you") ${empty requestScope.value1} = false
request.setAttribute("value4","i love you") ${!empty requestScope.value1} = true