JSP原理剖析

和servlet一样，动态web技术HTML只给静态页面，JSP可以嵌入JAVA代码，为用户提供动态数据
继承HttpJspbase

地址–work工作间：C:UsersHPAppDataLocalJetBrainsIntelliJIdea2020.1tomcat

将jsp转成java文件

JSP最终转换成JAVA类

HttpJspbase继承了Servlet–Jsp本质是个servlet

 	final javax.servlet.jsp.PageContext pageContext;	//页面上下文
    javax.servlet.http.HttpSession session = null;	//Session
    final javax.servlet.ServletContext application;	//Application
    final javax.servlet.ServletConfig config;		//config
    javax.servlet.jsp.JspWriter out = null;
    final java.lang.Object page = this;	//当前page
    request	//请求
    response	//相应

输出前增加的代码

  	response.setContentType("text/html");
      pageContext = _jspxFactory.getPageContext(this, request, response,
      			null, true, 8192, true);
      _jspx_page_context = pageContext;
      application = pageContext.getServletContext();
      config = pageContext.getServletConfig();
      session = pageContext.getSession();
      out = pageContext.getOut();
      _jspx_out = out;

HTML标签使用out.write()方法输出

 	out.write("n");
      out.write("n");
      out.write("n");
      out.write("n");
      out.write("n");
      out.write("n");

    


<%
	//可以使用内置的类
    String name="csf";	//<%  %>中可使用java代码
%>
name:<%=name%>	//获取java中的变量

当访问jsp文件时，生成jsp文件与编译的.class文件