JSP

1. page

2. include

3. taglib

jsp页面中不需要创建，直接使用的对象<br>&nbsp;*&nbsp;一共有9个：<br>&nbsp;&nbsp;&nbsp;变量名&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 真实类型&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 作用<br>&nbsp;&nbsp;*&nbsp;pageContext&nbsp; &nbsp; &nbsp; PageContext&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;当前页面共享数据，还可以获取其他八个内置对象<br>&nbsp;&nbsp;*&nbsp;request&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;HttpServletRequest&nbsp; &nbsp; 一次请求访问的多个资源(转发)<br>&nbsp;&nbsp;*&nbsp;session&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;HttpSession&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 一次会话的多个请求间<br>&nbsp;&nbsp;*&nbsp;application&nbsp;&nbsp;&nbsp;&nbsp;ServletContext&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;所有用户间共享数据<br>&nbsp;&nbsp;*&nbsp;response&nbsp; &nbsp; &nbsp; HttpServletResponse&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 响应对象<br>&nbsp;&nbsp;*&nbsp;page&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Object&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 当前页面(Servlet)的对象&nbsp;&nbsp;this<br>&nbsp;&nbsp;*&nbsp;out&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; JspWriter&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 输出对象，数据输出到页面上<br>&nbsp;&nbsp;*&nbsp;config&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;ServletConfig&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Servlet的配置对象<br>&nbsp;&nbsp;*&nbsp;exception&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Throwable&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;异常对象

Expression&nbsp;Language&nbsp;表达式语言

1.&nbsp;运算

2.&nbsp;获取值