JSP EL表达式
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2022-04-07 16:54:27
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<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>EL表达式的介绍</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
</head>
<body>
<%
session.setAttribute("username" , "libinxuan");
String[] week = {"星期一","星期二","星期三","星期四","星期五","星期六","星期天"};
session.setAttribute("week", week);
%>
<table border="1">
<tr>
<td><b>运算符</b></td>
<td><b>EL 表达式</b></td>
<td><b>运算结果</b></td>
</tr>
<tr>
<td>加法</td>
<td>\${10+10}</td>
<td>${10+10}</td>
</tr>
<tr>
<td>比较</td>
<td>\${101 gt 10}</td>
<td>${101 > 10}</td>
</tr>
<tr>
<td>比较</td>
<td>\${10 == 10}</td>
<td>${10 == 10}</td>
</tr>
<tr>
<td>读取数组</td>
<td>\${sessionScope.username}</td>
<td>${sessionScope.username}</td>
</tr>
<tr>
<td>读取变量</td>
<td>\${sessionScope.week['1']}</td>
<td>${sessionScope.week['1']}</td>
</tr>
</table>
</body>
</html>
设置不使用EL表达式有两种方法：
- jsp中修改%@page isELIgnored="true" %
- web.xml修改
<?xml version="1.0" encoding="UTF-8"?> <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> <jsp-config> <jsp-property-group> <url-pattern>*.jsp</url-pattern> <el-ignored>true</el-ignored> </jsp-property-group> </jsp-config> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> </web-app>
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