获取域值、全域查找、表达式
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ page import="com.itheima.domain.*" %>
<%@ page import="java.util.*" %>
<!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>
<%
pageContext.setAttribute("company", "ssss");
//request存储字符串
request.setAttribute("company", "程序员");
//session存储一个对象
User user = new User();
user.setId(1);
user.setName("zhangsan");
user.setPassword("123");
session.setAttribute("user", user);
//application存储一个集合
List<User> list = new ArrayList<User>();
User user1 = new User();
user1.setId(2);
user1.setName("lisi");
user1.setPassword("123");
list.add(user1);
User user2 = new User();
user2.setId(3);
user2.setName("wangwu");
user2.setPassword("123");
list.add(user2);
application.setAttribute("list", list);
%>
<%=request.getAttribute("company") %>
<%
User sessionUser = (User)session.getAttribute("user");
out.write(sessionUser.getName());
%>
<hr/>
${requestScope.company }
${sessionScope.user.name }
${applicationScope.list[1].name}
${company }
${user.name }
${list[1].name}
${1+1 }
${1==1?true:false }
${empty list}
</body>
</html>
输出如下：
程序员 zhangsan
--------------------------------------------------------------------------------
程序员 zhangsan wangwu ssss zhangsan wangwu 2 true false
${pageContext.request.contextPath}
<form action="${pageContext.request.contextPath }/el/form2.jsp" method="post">
<input type="text" name="username"><br>
<input type="password" name="password"><br>
<input type="checkbox" name="hobby" value="zq">足球
<input type="checkbox" name="hobby" value="pq">排球
<input type="checkbox" name="hobby" value="ppq">乒乓球
<br>
<input type="submit" value="提交"><br>
</form>
${pageContext.request }
输出如下：
org.apache.catalina.connector.RequestFacade@7d9d2615
<%=pageContext.getRequest().getContextPath%> 这句代码不能实现
获得WEB应用的名称
jstl
<body>
<%
request.setAttribute("count", 10);
%>
<c:if test="${count==10 }">
xxxx
</c:if>
<c:forEach begin="0" end="5" var="i">
${i }
<br/>
</c:forEach>
<c:forEach items="${productList }" var="pro">
${pro.pname }
</c:forEach>
</body>
输出
xxxx 0
1
2
3
4
5
c:if
<c:if test="${empty user}">
<li><a href="login.jsp">登录
</a></li>
<li><a href="register.jsp">注册
</a></li>
</c:if>
<c:if test="${!empty user}">
<li>${user.name }
</li>
<li><a href="#">提出
</a></li>
</c:if>
模拟登陆
<%
//模拟用户已经登录成功
User user = new User();
user.setId(100);
user.setName("张三");
user.setPassword("123");
session.setAttribute("user", user);
%>
c:forEach
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ page import="java.util.*" %>
<%@ page import="com.itheima.domain.*" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!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>
<%
//request模拟List<String> strList
List<String> strList = new ArrayList<String>();
strList.add("itcast");
strList.add("itheima");
strList.add("boxuegu");
strList.add("shandingyu");
request.setAttribute("strList", strList);
//application遍历List<User>的值
List<User> userList = new ArrayList<User>();
User user1 = new User();
user1.setId(2);
user1.setName("lisi");
user1.setPassword("123");
userList.add(user1);
User user2 = new User();
user2.setId(3);
user2.setName("wangwu");
user2.setPassword("123");
userList.add(user2);
application.setAttribute("userList", userList);
//session遍历Map<String,String>的值
Map<String,String> strMap = new HashMap<String,String>();
strMap.put("name", "lucy");
strMap.put("age", "18");
strMap.put("addr", "西三旗");
strMap.put("email", "licy@itcast.cn");
session.setAttribute("strMap", strMap);
//request遍历Map<String,User>的值
Map<String,User> userMap = new HashMap<String,User>();
userMap.put("user1", user1);
userMap.put("user2", user2);
request.setAttribute("userMap", userMap);
%>
<h1>取出strList的数据
</h1>
<c:forEach items="${strList }" var="str">
${str }
<br/>
</c:forEach>
<h1>取出userList的数据
</h1>
<c:forEach items="${userList}" var="user">
user的name：${user.name }------user的password：${user.password }
<br/>
</c:forEach>
<h1>取出strMap的数据
</h1>
<c:forEach items="${strMap }" var="entry">
${entry.key }====${entry.value }
<br/>
</c:forEach>
<h1>取出userMap的数据
</h1>
<c:forEach items="${userMap }" var="entry">
${entry.key }:${entry.value.name }--${entry.value.password }
<br/>
</c:forEach>
</body>
</html>
输出：
取出strList的数据
itcast
itheima
boxuegu
shandingyu
取出userList的数据
user的name：lisi------user的password：123
user的name：wangwu------user的password：123
取出strMap的数据
name====lucy
addr====西三旗
age====18
email====licy@itcast.cn
取出userMap的数据
user1:lisi--123
user2:wangwu--123
