JSTL--测试EL表达式--drp212

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JSTL(JSP标准标签库-JSP Standard Tag Library):

<c:out>

<c:if>

<c:choose><c:when><c:otherwise>

<c:forEach>

<fmt:formatNumber>

<fmt:formatDate>

EL(EL表达式-Expression language):

 

index.jsp

<%@ page language="java" import="java.util.*" pageEncoding="GB18030"%>
<%
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>My JSP ‘index.jsp‘ starting page</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">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->
  </head>
  
  <body>
   	<a href="servlet/JstlElServlet">jstl表达式</a>
     <br>
  </body>
</html>

 web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0"
    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_3_0.xsd">
 
	 <servlet>
	 	<servlet-name>JstlElServlet</servlet-name>
	 	<servlet-class>com.bjpowrnode.jstl.JstlElServlet</servlet-class>
	 </servlet>
	<servlet-mapping>
		<servlet-name>JstlElServlet</servlet-name>
		<url-pattern>/servlet/JstlElServlet</url-pattern>
	</servlet-mapping>
		
</web-app>

 JstlElServlet

/**
 * 
 */
package com.bjpowrnode.jstl;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * @ClassName:JstlElServlet
 * @Description:测试EL表达式
 * @author wm
 * @date 2016年2月14日下午8:45:38
 */
public class JstlElServlet extends HttpServlet {

	@Override
	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		//普通字符串
		request.setAttribute("hello", "Hello World");
		request.getRequestDispatcher("/jstl_el.jsp").forward(request, response);;
	}


}

 jstl_el.jsp

<%@ page language="java" contentType="text/html; charset=GB18030"
    pageEncoding="GB18030"%>
<!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=GB18030">
<title>Insert title here</title>
</head>
<body>
	<h1>测试EL表达式</h1>
	<hr>
	<li>普通字符串</li><br>
	hello(jsp脚本):<%=request.getAttribute("hello") %></br>
	hello(El表达式:语法:$和{}:${hello}<br>
	hello(el表达式,el内置对象,	pageScope,requestScope,sessionScope,applicationScope	)<br>
	如果不指定范围,它的搜索范围就是pageScope~applicationScope():${requestScope.hello}<br>
	hello(el表达式,从session中取得):${sessionScope.hello}<br>
</body>
</html>

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