pageContext
通过pageContext获取servletContext,request,response,session等对象
格式${pageContext.request.locale}
获取request中用户请求的值${param.name}
获取请求头信息${headers['Content-Type']}(如果定义的字段含有-等关键词也可以采用这样)
获取cookie值${cookie.cookeName.value}
获取context-param${initParam.name}
获取request中用户请求的值:
userName:<%=request.getParameter("name") %>
password:<%=request.getParameter("pwd") %>
<hr>
userName:${param.name}
password:${param["user-pwd"]}
获取头
user-agent:<%=request.getHeader("user-agent") %><br>
user-agent:${header["user-agent"] }
获取web的context-param配置信息
web.xml代码
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
<display-name>el</display-name>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
<context-param>
<param-name>test</param-name>
<param-value>123123</param-value>
</context-param>
</web-app>
index页面获取方式
Context-Param:${initParam.test}<br>
Context-Para“”m:<%= application.getInitParameter("test")%>
获取Cookie
cookie:${cookie.test.value}<br>
<% Cookie cookies[]=request.getCookies();
String s=cookies[1].getValue();
%>
cookie:<%= s%>
获取隐式作用域对象中保存的属性
${user.name}按照pageScope，requestScope，sessionScope，applicationScope的顺序查找
${pageScope.user.name}只在pageContext中查找（指定范围）
流程介绍
1.
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"
%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>ELbiaodahshi</title>
</head>
<body>
<form action="control/doForm.jsp" method="post">
<p>login</p>
<p>name:<input type="text" name="name"></p>
<p>password:<input type="password" name="pwd"></p>
<p><button type="reset">cancel</button>
<button type="submit">submit</button></p>
</form>
<hr>
</body>
</html>
2.
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<jsp:useBean id="user" class="el.User" scope="request"></jsp:useBean>
<jsp:setProperty property="*" name="user"/>
<jsp:forward page="../show.jsp"/>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
userName1:<%=request.getParameter("name") %>
password1:<%=request.getParameter("pwd") %>
<hr>
userName2:${param.name}
password2:${param["pwd"]}
<br>
</body>
</html>
3.
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"
import="el.User"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
userName:${user.name}
<%User user=(User)pageContext.findAttribute("user"); %>
password:${requestScope.user.pwd}
<%=user.getPwd() %>
</body>
</html>
3
package el;
public class User {
private String name;
private String pwd;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPwd() {
return pwd;
}
public void setPwd(String pwd) {
this.pwd = pwd;
}
}
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