EL表达式学习笔记(JSTL)

<%@ page language="java" import="java.util.*" pageEncoding="GB18030"%>

<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>



  
    
    
    
    
	
	
	    
	
	
	

  
  
  
    
测试EL表达式
	

	
普通字符串
	hello(jsp脚本):<%request.getAttribute("hello");%>

	hello(EL表达式使用$和{}):${hello}

	hello(el表达式,el的隐含对象：pageScope,requestScope,sessionScope,applicationScope
如果没有指定scope，则它的搜索顺序为
	pageScope ----> applicationScope):${requestScope.hello }

	
	
结构
	姓名：${user.userName}(与对象的方法(get)相关)

	年龄：${user.age }

	所属组：${user.group.name }

	
	
输出map
	mapvalue.key1:${mapvalue.key1 }

	mapvalue.key2:${mapvalue.key2 }

	
	
数组输出，采用[]和下标
	atrarray[2]:${astarray[1] }

	
	
输出对象数组
	userarray[3].username:${users[2].username }

	
	
输出list,采用[]和下标
	userlist[5].username:${userlist[4].username }

	
	
el表达式对运算符的支持
	1 + 2 = ${1+2 }

	10 / 5 = ${10/5 }

	10 / 5 = ${10 div 5 }

	10 % 3 = ${10%3 }

	10 % 3 = ${10 mod 3 }

	<--
		==    eq
		!=    ne
		<     lt
		>     gt
		<=    le
		>=    ge
		&&    and
		||    or
		!     not
		/     div
		%     mod
	-->
	
	
测试empty
	value1:${not empty value1 }

	value2:${empty value1 }

	value3:${empty value1 }

	value4:${empty value1 }

	
  

 

转载于:https://www.cnblogs.com/hbiao68/archive/2011/10/19/2218244.html