190718-04(JSP 九大内置对象){content}

JSP 九大内置对象，都是位于jsp_java文件里的_jspService方法中可以直接使用的对象，记忆时使用4+2+3

pageContext --- javax.servlet.jsp.

request --- javax.servlet.http.HttpServletRequest

session --- javax.servlet.http.HttpSession

application --- javax.servlet.http.httpSessin

out --- javax.servlet.jsp.JspWriter

response --- javax.servlet.http.HttpServletResponse

page --- 本质就是当前servlet对象，java.lang.Object

config --- javax.servlet.ServletConfig

exception --- java.lang.Throwable