jsp复习笔记

1.jsp技术是用JAVA语言作为脚本语言的。
2.<% %> <%= %>
3.<%! %>
4.form表单
enctype=”” application默认 multipart/form-data文件字节流
URL参数值长度不能超过2K
get post
action=”提交路径”
5.三大指令 page taglib include

 <%@指令 [属性] %>  <%@ page contentType="text/html;charset=UTF-8" language="java" import="" pageEncoding="utf-8"%>  contentType 从服务器端到客户端的语言类型，此页编码方式  language="java" java语言  import="" 引入包  pageEncoding="utf-8" 此页request接收到参数以什么字符集来编码  (注意：三个地方UTF-8   再加上<meta charset="utf-8">  )  <%@ include file="文件路径名"%> 缺陷：不方便传参，把代码都会include进去，所以要避免首部尾部标签重复  <%@ taglib%>

6.jsp六个基本动作

  <jsp:useBean id="a" class="com.lyf.Animal">//动作实例化    <jsp:setProperty name="a" property="name" value="cat"/>  </jsp:useBean>  <jsp:getProperty name="a" property="name">      <jsp:include page="" >//动作include 可以传参  <jsp:include file="index.jsp">      <jsp:param name="username" value='<%=java.net.URLEncoder.encode("中文","utf-8")%>'/>  </jsp:include>      <%          String name=request.getParameter("username");      %>      <%=java.net.URLDecoder.decode("中文","utf-8")%>  <jsp:forward page="">//一次请求     <jsp:param name="username" value='<%=java.net.URLEncoder.encode("中文","utf-8")%>'/>  </jsp:forward>

7.jsp内置对象

  page<request<session<application  out response request session config application exception pageContext page  out.println(""）源代码换行，实际效果不换行  request.getParamter request.getCookies request.setAttribute request.getAttribute  request.getSession request.getParameterValues request.getParameterNames  response.addCookie response.setContentType response.sendRedirect response.setHeader

8.session//用于会话请求，可以跨页请求 request//用于一次请求

 session.setAttribute session.getAttribute session.removeAttribute   设置session时间   web.xml   <session-config>      <session-timeout>30</session-timeout>//30分钟   </session-config>

9.application//所有页都可以传 可用于在线访客

  web.xml  <context-param>  <param-name>count</param-name>  <param-value>1000</param-value>  </context-param>  <%   String count=application.getInitParameter("count");   if(application.getAttribute("num")==null)  {       application.setAttribute("num",count);  }  int num=Integer.parseInt(application.getAttribute("num").toString());  application.setAttribute("num",++num);%>

10.pageContext//页面赋值

11.@include :指令，不能传参 先合成后编译
jsp:include :动作，能传参，先编译后合成

12.

response.setContentType("text/html");//相应格式   response.setRedirect(""); //window.location    Cookie c=new Cookie("username","ff");    c.setMaxAge(3600*24*7);   response.addCookie(c);    Cookie[] cookies=request.getCookies();    for(Cookie c:cookies){       if(c.getName().equals("ff"){       }    }