JSTL c标签库remove方法的使用

JSTL  c标签库remove方法的使用

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>


<% 
	request.setAttribute("test", "aaaaaa");
	pageContext.setAttribute("test", "bbbbbb");
	session.setAttribute("test", "cccccc");
	application.setAttribute("test", "dddddddd");
%>

${test}     


${test==null?"null":test}