区别：
jsp=html+java web混合
语法较为复杂难以编写
如if语句编写如下：
<body>
<%
if(flag){
%>
<h2>欢迎 <%=name %></h2>
<%} %>
</body>
需要将java语句套在<% %>中
jstl书写较为简便if语句如下：
<body>
jstltest <br><br>
<c:if test="${flag== true}">
欢迎${name}
<c:out value="${name}" />
</c:if>
</body>
jstl的使用：
导入jar包
<dependency>
<groupId>jstl</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
foreach
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<c:forEach var="i" begin="1" end="10" step="1">
第<c:out value="${i}" />行
<br>
</c:forEach>
<hr>
</body>
</html>
choose
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!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>
<c:choose>
<c:when test="${age<12}">
小学阶段
</c:when>
<c:when test="${age>=12&&age<16}">
中学阶段
</c:when>
<c:when test="${age>=16&&age<30}">
大学阶段
</c:when>
<c:otherwise>
你猜
</c:otherwise>
</c:choose>
</body>
</html>
if
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
jstltest <br><br>
<c:if test="${flag== true}">
欢迎${name}
<c:out value="${name}" />
</c:if>
</body>
</html>