JSTL中Core的使用

先下载JSTL,然后将jstl.jar, standard.jar两个jar包copy到lib下,   将要使用的Core标签中的c.tld文件copy到WEB-INF下,修改web.xml文件
<?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>
  	<taglib>
  		<taglib-uri>jstl-c</taglib-uri>
  		<taglib-location>/WEB-INF/c.tld</taglib-location>
  	</taglib>
  </jsp-config>
  
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
</web-app>
 定义一个taglib.jsp用于引入标签
<%@ taglib prefix="c" uri="jstl-c"%>
 
先看out标签的使用
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8" %>
<%@include file="taglib.jsp" %>
<%
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>c:out的使用</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>
    <h2 align="center">c:out 的作用就相当于<%="param1" %></h2><br>
    <h3>输出value的值要是value为空就输出default的值,escapeXml属性的值是转义用的</h3>
    <br><br>
    <c:out value="学习JSTL"></c:out><br>
    <c:out value="${sessionScope.username}" default="libinxuan"></c:out><br>
    <c:out value="${username}" default="libinxuan"></c:out><br>
	<c:out value="<h1>学习JSTL</h1>" escapeXml="false"></c:out><br>
	<c:out value="<h1>学习JSTL</h1>" escapeXml="true"></c:out><br>
  </body>
</html>
 set的使用
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@taglib uri="jstl-c" prefix="c" %>
<%
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>c:set的用法</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>
    <h2 align="center">作用是将变量保存到JavaBeans属性中或JSP页面的特定取值范围</h2><br><br>
    <h2>各属性的含义:</h2><br>
    <h3>    value: 要保存的内容,可以是EL表达式或常量</h3><br>
    <h3>    target: 要修改属性的对象名,一般为JavaBeans对象名</h3><br>
    <h3>    property: 要修改的JavaBeans的属性</h3><br>
    <h3>    var: 要保存内容的变量的名称</h3><br>
    <h3>    scope: 保存内容的作用范围</h3><br><br><br>
    <h2>注意: 指定了target属性就要同时指定property属性</h2><br><br>
    <c:set value="libinxuan" var="username" scope="session"></c:set><br>
    <c:set value="libinxuan" var="user" scope="session"></c:set><br>
    <c:set var="username2" scope="session">libinxuan</c:set><br><br>
    <h2>将value的值保存到target对象的propertyName属性中</h2><br>
    <c:out value="${sessionScope.user}" default="sss"></c:out>
  </body>
</html>
 remove的使用
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@taglib uri="jstl-c" prefix="c" %>
<%
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>c:remove的使用</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>
    <h2 align="center">作用是删除所设定的变量</h2><br><br>
    <h3>删除session中名为username的属性的值</h3><br>
    <c:remove var="username" scope="session"/>
  </body>
</html>
 if的使用
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@include file="taglib.jsp" %>
<%
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>c:if的使用</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>
  	<c:set value="libinxuan" var="name" scope="session"></c:set>
  	<c:out value="${sessionScope.name}"></c:out><br>
    <c:if test="${sessionScope.name == 'libinxuan'}">
    	欢迎管理员登录
    </c:if><br>
    <c:if test="${1>0}">
    	你好
    </c:if>
  </body>
</html>
 choose的使用,这里要借助一个jsp的请求input.jsp
<%@ 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>用于测试choose,when,otherwise</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>
  	<form action="choose.jsp">
    	请输入你的年龄:<input type="text" name="age" id="age" >
    	<input type="submit" value="提交" >
    </form>	
  </body>
</html>
 
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@taglib uri="jstl-c" prefix="c" %>
<%
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>c:choose,c:when,s:otherwise的使用</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>
    <c:choose>
    	<c:when test="${param.age>70}">
    		老人
    	</c:when>
    	<c:when test="${param.age<=70 and param.age>=35 }">
    		中年人
    	</c:when>
    	<c:when test="${param.age>=0 and param.age<=35 }">
    		年轻人
    	</c:when>
    	<c:otherwise>
    		你不是人
    	</c:otherwise>
    </c:choose>
  </body>
</html>
 forEach的使用
<%@ page language="java" import="java.util.*"  pageEncoding="UTF-8"%>
<%@include file="taglib.jsp" %>
<%
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>c:forEach标签的使用</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">
	<%
    	String names[] = new String[4];
    	names[0]="张三";
    	names[1]="李四";
    	names[2]="王五";
    	names[3]="张六";
    	pageContext.setAttribute("names",names);
    %>
  </head>
  
  <body>
  	<h2 align="center">用于迭代字符串,数组,集合</h2>
    <h2>各属性的介绍:</h2><br/>
    <h3>     begin: 开始的索引</h3><br>
    <h3>     end: 介绍的索引</h3><br>
    <h3>     step: 步长</h3><br>
    <h3>     var: 当前迭代变量的名称</h3><br>
    <h3>     items: 进行循环的集合</h3><br>
    <h3>     varStatus: 显示循环状态的变量</h3><br>
    <c:forEach items="${names}" var="name" varStatus="i">
    	${name}<br>
    	${i.index}<br>
    </c:forEach>
  </body>
</html>
 

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