EL表达式-笔记1

<%@page import="com.entity.user"%>

<jsp:userbean id="pserson" class="com.entity.user">

<c:set target="${person}" property="name" value="asd">

<c:set target="${person}" property="age" value="30">

<c:out value= "${person}">

EL表达式运算

常量输出：${10}

四则运算：${10 + 2},${10 - 2},${10 * 2},${10 / 2},${10 div 2}

等于：${10 == 10},${10 eq 10}

不等于：${10 != 2},${10 ne 2}

取余：${10 % 3},${10 mod 3}

小于：${5 < 10},${5 lt 10}

大于：${5 > 10},${5 gt 10}

小于等于：${5 <= 10},${5 le 10}

大于等于：${5 >= 3},${5 ge 3}

逻辑与：${true && true},${true and true}

逻辑或：${true || false},${true or false}

逻辑非：${!true},${not true}

判空：${empty ""}

非空判断：${empty not ''}

 

取值

<%

       string username = request.getParameter("username");

       string password = request.getParameter("password");

%>

<%=username%>

<%=password%>

 

<%${param.username}%>

<%${param.password}%>

 

头信息接收

${header.Host}

获取cookie信息

response.addCookie(new Cookie("pwd","123"))

${cookie.pwd.name},${cooklie.pwd.value}

 

 

域对象

<%

Person person = new Persong();

person.setAge(30);

persong.setId(1);

persong.setName("asd");

pageContext.setAttribute("persong",person);

request.setAttribute("person",person);

session.setAttribute("person",person);

application.setAttribute("person",person);

%>

<%

Persong p = pageContext.getAttribute("persong");

%>

${pageScope.person.id}

${requestScope.person.name}

${sessionScope.person.age}

${applicationScope.person.age}