We can specify the order in which we want to initialize various
Servlets.
Like first initialize Servlet1 then Servlet2 and so on.
This is
accomplished by specifying a numeric value for the
<load-on-startup>
tag.
<load-on-startup> tag specifies that the servlet should be
loaded
automatically when the web application is started.
The value is
a single positive integer, which specifies the loading
order. Servlets with
lower values are loaded before servlets with
higher values (ie: a servlet
with a load-on-startup value of 1 or 5 is
loaded before a servlet with a
value of 10 or 20).
When loaded, the init() method of the servlet is
called. Therefore
this tag provides a good way to do the
following:
start any daemon threads, such as a server listening on a
TCP/IP port,
or a background maintenance thread
perform initialisation of
the application, such as parsing a settings
file which provides data to other
servlets/JSPs
If no <load-on-startup> value is specified, the servlet
will be loaded
when the container decides it needs to be loaded - typically
on it's
first access. This is suitable for servlets that don't need to
perform
special initialisation.
I hope that clears all the doubts
regarding <load-on-startup> in web.xml.
|
|
