Javaweb Study Records (17)--jsp Nine hidden Objects

public void _jspservice (httpservletrequest request,

HttpServletResponse response)

Throws Java.io.IOException, Servletexception

{

Jspfactory _jspxfactory = null;

PageContext PageContext = null;

HttpSession session = NULL;

ServletContext Application = null;

ServletConfig config = null;

JspWriter out = null;

Object Page = this;

throwable exception =

Org.apache.jasper.runtime.JspRuntimeLibrary.getThrowable (Request);

if (Exception! = null) {

Response.setstatus (Httpservletresponse.sc_internal_server_error);

}

¨ each JSP page is accessed for the first time, the Web container will hand over the request to the JSP engine (that is, a Java program) to handle. The JSP engine first translates the JSP into a _jsp servlet (essentially a servlet) and then invokes it in the way the servlet calls. ¨ because the JSP is translated into a servlet on the first visit, the first visit is usually slow, but the second access, the JSP engine if it finds that the JSP has not changed, is no longer translated, but directly called, so the execution efficiency of the program will not be affected. The ¨jsp engine, when invoking the _jspservlet of the JSP, passes or creates 9 Web development-related objects for _jspservlet use. JSP technology designers for developers to write JSP pages when they get references to these Web objects, deliberately defined 9 corresponding variables, developers in the JSP page through these variables can quickly get these 9 large object references.

Javaweb Study Records (17)--jsp Nine hidden Objects