Different between ServleConfig and ServletContext

Many servlet’s developers are confuse about the different between “ServletConfig” and “ServletContext”. Actually the “ServletContext” name is quite confusing, it should change to “AppConfig” or “AppContext” in the future release :)

ContextConfig

1) This is one per “web application”, access globally by all the servlets’ class
2) web.xml – within the web-app element and outside the servlet element


    <web-app ...>
        <servlet>
		<servlet-name>ServletName</servlet-name>
		<servlet-class>com.mkyong.ServletDemo</servlet-class>
	</servlet>
	
	<context-param>
			<param-name>email</param-name>
			<param-value>admin@email.com</param-value>
	</context-param>
   </web-app>

3) Servlet code


getServletContext().getInitParameter("email")

==> See the ServletContext example here

ServletConfig

1) This is one per “servlet”, only access for each specific servlet
2) web.xml – within the servlet element


    <web-app ...>
        <servlet>
		<servlet-name>ServletName</servlet-name>
		<servlet-class>com.mkyong.ServletDemo</servlet-class>

                 <init-param>
			<param-name>email</param-name>
			<param-value>admin@email.com</param-value>
	         </init-param>

	</servlet>
   </web-app>

3) Servlet code


getServletConfig().getInitParameter("email")

==> See the ServletContext example here

About the Author

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mkyong
Founder of Mkyong.com, love Java and open source stuff. Follow him on Twitter. If you like my tutorials, consider make a donation to these charities.

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saina rajaNoo Alammkyongtechbrainless Recent comment authors
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saina raja
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saina raja

Sir ur tutorial is very understable….
I am really amazed of ur explaination…..I am also one of ur fan….

Noo Alam
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Noo Alam

Nice and i am a fan of your Java tutorial.

Noor Alam
(SCJP,SCWCD,SCBCD)

techbrainless
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techbrainless

Hi Thanks , it is really amazing tutorial ,

but just one question what do u mean by

one per “web application” & This is one per “servlet” ?

I think so we can have multiple initial parameters per servlet and per web.xml