Скачать или смотреть 126 Difference between getRequestDispatcher and getNamedRequestDispatcher method adv java servlet tu

What is the difference between getRequestDispatcher() and getNamedRequestDispatcher() method? #advance #java #servlet #programming #tutorial

getRequestDispatcher() getNamedRequestDispatcher()
--------------------------- -----------------------------
1)Invokable on request, 1)Invokable on ServletContext
ServletCOntext object object.

2)Expects URL pattern of 2)Expects logical-name or
destination Servlet program servlet-name argument of
as argument value. destination servlet program as
argument value.

3)Can give RequestDisptcher 3)can give RequestDispatcher
object pointing to servlet object pointing to servlet
program, JSP program, HTML program, JSP program
program

#Creating RequestDispatcher object pointing to destination JSP/html program:
1)
ServletContext sc=getServletContext();
RequestDispatcher rd=sc.getRequestDispatcher("/test.jsp");
OR
RequestDispatcher rd=request.getRequestDispatcher("/test.jsp");

2)
RequestDispatcher
rd1=request.getRequestDispatcher("/index.html");

RequestDispatcher
rd2=sc.getRequestDispatcher("/index.html");


Note: We can configure JSP, Servlet programs in web.xml file but we can not configure html programs in web.xml(except welcome-file-configuration tag). Eventhough Conguring .html file is optional in web.xml

We must configure Servlet program in web.xml file having
logical-name(Or @WebServlet), url-pattern.

Configuration of JSP programs in web.xml file is optional. But we can cofigure.


In servlet chaining/collaboration the destination program can be servlet program or non-servlet program but Sourc program must be servlet


Question:
What is difference between creating RequestDispatcher object using Request object and ServletContext object?

ServletContext sc=getServletContext();
RequestDispatcher rd=sc.getRequestDispatcher("/test.jsp");
OR
RequestDispatcher rd1=request.getRequestDispatcher("/test.jsp");