JavaWeb之JSTL标签库

（1）Core标签库

<c:out>

jstl1.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%><!-- 引入JSTL核心标签库 -->
<!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>JSTL标签库</title>
</head>
<body>
	
	<!-- escapeXml默认值为true -->
	<c:out value="小小的太阳" escapeXml="true"></c:out><br>
	
	<!-- param中不存在name属性，value的值为 null，通过default属性输出默认值 -->
	<c:out value="${param.name}" default="unknown"></c:out><br>
	
	<!-- 由于escapeXml设置为false,此时不转义html,因此5秒后跳转到百度页面 -->
	<c:out value="${param.name}" escapeXml="false">
		<!-- 也可以通过标签体输出默认值 -->
		<meta http-equiv="refresh" content="5;url=http://www.baidu.com"/>
	</c:out><br>
	
</body>
</html>

访问：http://localhost:8080/JavaWeb1/jstl1.jsp。5秒后跳转到百度页面

加参数，访问：http://localhost:8080/JavaWeb1/jstl1.jsp?name=xxdty

此时，${param.name}不为null，所以输出${param.name}的值

<c:set>

jstl2.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8" import="java.util.*"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%><!-- 引入JSTL核心标签库 -->
<!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>JSTL标签库</title>
</head>
<body>
	
	<!-- 属性名为name,值为xxdty，在session域中 -->
	<c:set var="name" value="xxdty" scope="request"></c:set>
	<c:out value="${requestScope.name }"></c:out><br>
	
	<!-- 也可以通过标签体为属性赋值 -->
	<c:set var="sex" scope="session">man</c:set>
	<c:out value="${sessionScope.sex }"></c:out><br>
	
	<!-- 为JavaBean属性赋值 -->
	<jsp:useBean id="user" class="zh.el.demo.User" scope="page"></jsp:useBean><!-- 创建user对象 -->
	<c:set target="${pageScope.user }" property="name" value="小龙女"></c:set>
	<c:set target="${pageScope.user }" property="age" value="18"></c:set>
	<c:out value="${pageScope.user.name }"></c:out><br>
	<c:out value="${pageScope.user.age }"></c:out><br>
	
	<!-- 为Map集合属性赋值 -->
	<%
		Map<String,String> map = new HashMap<String,String>();
		request.setAttribute("map", map);
	 %>
	 <c:set target="${requestScope.map }" property="man" value="姬如雪"></c:set>
	 <c:set target="${requestScope.map }" property="woman" value="女帝"></c:set>
	 <c:out value="${requestScope.map.man }"></c:out><br>
	 <c:out value="${requestScope.map.woman }"></c:out><br>
	
</body>
</html>

访问：http://localhost:8080/JavaWeb1/jstl2.jsp

<c:remove>

jstl3.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%><!-- 引入JSTL核心标签库 -->
<!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>JSTL标签库</title>
</head>
<body>
	
	<c:set var="company" value="HW" scope="request"></c:set>
	<c:set var="school" value="JH" scope="request"></c:set>
	<c:out value="${requestScope.company }"></c:out><br>
	<c:out value="${requestScope.school }"></c:out><br>
	
	<!-- 移除属性 -->
	<c:remove var="company" scope="request"/>
	<%-- <c:remove var="school" scope="request"/> --%>
	<c:out value="${requestScope.company }"></c:out><br>
	<c:out value="${requestScope.school }"></c:out><br>
	
</body>
</html>

访问：http://localhost:8080/JavaWeb1/jstl3.jsp

<c:remove>

jstl4.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%><!-- 引入JSTL核心标签库 -->
<!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>JSTL标签库</title>
</head>
<body>
	
	<!-- 捕获的异常对象以指定名称保存在page域 -->
	<c:catch var="myException">
		<%
			int i = 1 / 0;
		 %>
	</c:catch>
	
	<c:out value="${pageScope.myException }"></c:out><br>
	
</body>
</html>

访问：http://localhost:8080/JavaWeb1/jstl4.jsp

<c:if>

jstl5.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%><!-- 引入JSTL核心标签库 -->
<!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>JSTL标签库</title>
</head>
<body>
	
	<c:set var="a" value="1" scope="page"></c:set>
	
	<c:if test="${a eq 1 }" var="a" scope="page">
		逻辑表达式为真
	</c:if>
	
</body>
</html>

访问：http://localhost:8080/JavaWeb1/jstl5.jsp

<c:choose>、<c:when>、<c:otherwise>

jstl6.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%><!-- 引入JSTL核心标签库 -->
<!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>JSTL标签库</title>
</head>
<body>
	
	<c:choose>
		<c:when test="${empty param.job}">
			unknown job
		</c:when>
		<c:when test="${param.job eq 'boss' }">
			it is a boss!
		</c:when>
		<c:otherwise>
			it is not a boss!
		</c:otherwise>
	</c:choose>
	
</body>
</html>

<c:forEach>

（2）Functions标签库

JavaWeb之JSTL标签库

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