General
syntax:
<%@ directive attribute=”value” %>
Possible
directives in the JSP are: page, include, taglib
PAGE DIRECTIVE:
(1) <%@
page info=”JSP page” %>
à Info on the
page that can be accessed through Servlet.getServletInfo() method.
Public String getServletInfo()
{ return
“JSP example”;
}
(2) <%@
page language=”java” %>
à tells the
server what language will be used in the file. Java is only supported for
current specification.
(3) <%@
page import="java.applet.*, java.util.*" %>
à
Specify
java package and classes to be imported. It should always be placed at the top
of the JSP file.
(4) <%@ page
extends=”java.util.Dictionary” %>
à Normally,
extends is not used because by default every class extends HttpJspBase. But if
you do so HttpJspBase is replaced with java.util.Dictionary.
<%@ page
implements=”java.util.Dictionary” %>
à
It
follows the same rule as extends. It is for interface.
(5) <%@ page
buffer=”none/8kb/sizekb” %>
à
Controls
the size of the buffer associated with JspWriter. If you want unbuffered
output, set it to none.
à By default,
it is set to 8 KB. Use with autoflush.
<%@
page buffer=”9kb” autoFlush=”true/false” %>
à If
autoflush is “true”, it flushes the output buffer when it is full rather than
araising an exception. Buffering improves the spped since it is better to write
a large number of characters at the one go than a small number many times.
(6) <%@
page isThreadSafe=”true/false” %>
à If you want
the servlets to create multiple instances of itself then you must give
isThreadSafe=”false”. Default is true.
à By saying
“false”, the JSP engine will implements SingleThreadModel interface and it can
load multiple instances of servlets.
à If “true”,
singles JSP engine that the multiple client requests can be dealt with at once.
It is author’s job to synchronize shared state.
(7) <%@
page session=”true/false” %>
à By default
session is true. True means session data is avaible. Implicit variable named
session of type javax.servlet.http. HttpSession references current/new session
for the page.
à false means
that variable is not avaible.
(8) <%@
page contentType=”text/plain” %>
à By default it is “text/html”. This
info must come early in the file before any non-Latin-1 characters appear in
the file.
