Jsp的九种对象我简述之：
page
application
request
response
session
config
out
pageContext

page
<%@page contentType="text/html; charset=gb2312" language="java" import="java.sql.*" %>

response
<%
response.setHeader("Pragma","No-cache");
response.setHeader("Cache-Control","no-cache");
response.setDateHeader("Expires", 0);
%>

<%response.sendRedirect("login.jsp");%>

session
<%session.invalidate();%>

request/session
<%
String errmsg = request.getParameter("errmsg");
request.getSession(true);
String chk = "false";
session.putValue("Enter",chk);
%>

out
<%
if(errmsg != null && errmsg.equals("error1"))
out.print("你的用户号还没有开通!!");
else if(errmsg != null && errmsg.equals("error2"))
out.print("您输入管理员帐号或者密码不正确!!");
%>

下面是request对象在Java doc中的说明：其他类似