web容器会把jsp最终转化为servlet类，jsp中的如下标记将进行以下转化：html
<% ... %>：代码出如今方法内<%! ... %>：代码直接出如今类内（不在类内方法中）<%= ... %>：至关于<% out.print(...) %><%@ ... %>：指令
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%@ page import="servlet.*" %>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Test</title>
</head>
<body>
<h1>tests</h1>
<h2>
<%
String name = request.getAttribute("name").toString();
out.print(name);
%>
<%! int count=0 %>
<%= name %>
</h2>
</body>
</html>