<%@page import="java.util.ArrayList"%>
<%@page import="java.util.List"%>
<%@page import="com.atguigu.javaweb.Customer"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<!-- 7. EL 的运算符 -->
${param.score > 60 ? "及格" : "不及格" }
<br>
<%
List<String> names = new ArrayList<String>();
names.add("abc");
request.setAttribute("names", names);
%>
<!-- empty 可以作用于一个集合, 若该集合不存在或集合中没有元素, 其结果都为 true -->
names is empty: ${empty requestScope.names }
<br>
<!-- 6. 其他隐含对象: pageContext 等(cookie, header, initParam 只需了解.) -->
pageContext: pageContext 即为 PageContext 类型, 但只能读取属性就可以一直的 . 下去。
<br>
contextPath: ${pageContext.request.contextPath }
<br>
sessionId: ${pageContext.session.id }
<br>
sessionAttributeNames: ${pageContext.session.attributeNames }
<br>
initParam: ${initParam.initName }
<br>
Accept-Language: ${header["Accept-Language"] }
<br>
JSESSIONID: ${cookie.JSESSIONID.name } -- ${cookie.JSESSIONID.value }
<br>
<!-- 5. 与输入有关的隐含对象: param, paramValues -->
score: ${param.score }
<%--
<%= request.getParameter("score") %>
--%>
<br>
names: ${paramValues.name[0].class.name }
<%--
<%=
request.getParameterValues("name")[0].getClass().getName()
%>
--%>
<br>
<!-- 4. 隐含对象之与范围相关的: pageScope, requestScope, sessionScope, applicationScope -->
time: ${applicationScope.time.time }
<%--
<%= application.getAttribute("time") %>
--%>
<br>
<!-- 3. EL 可以进行自动的类型转换 -->
score: ${param.score + 11}
<br>
score: <%= request.getParameter("score") + 11 %>
<br>
<!-- 2. EL 中的隐含对象 -->
<%
Customer cust2 = new Customer();
cust2.setAge(28);
request.setAttribute("customer", cust2);
%>
age: ${customer.age }
<br>
<!-- 1. EL 的 . 或 [] 运算符 -->
age: ${sessionScope.customer["age"] }
<%--
Customer customer = (Customer)session.getAttribute("customer");
out.print(customer.getAge());
--%>
<%
Customer customer = new Customer();
customer.setName("ATGUIGU");
session.setAttribute("com.atguigu.customer", customer);
%>
<br>
<!--
如果域对象中的属性名带有特殊字符, 则使用 [] 运算符会很方便.
-->
name: ${sessionScope["com.atguigu.customer"].name }
</body>
</html>
