Spring : Need for the contextConfigLocation?

Question

In web.xml we have context parameter set named contextConfigLocation and defined as shown in the below code:

<context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>/WEB-INF/root-context.xml</param-value>
</context-param>

Also the same parameter is set in the Dispatch Servlet as shown below

<servlet>
    <servlet-name>spring</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
       <param-name>contextConfigLocation</param-name>
       <param-value>/WEB-INF/servlet-context.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
</servlet>

What is the difference between these two contextConfigLocations ?

You can take a look at this post: http://stackoverflow.com/questions/2069902/dd-elements-context-param-and-init-param-both-use-the-getinitparameter-me — Phoenix, Apr 08 '15 at 11:54

score 2 · Answer 1 · answered Apr 08 '15 at 11:59

2

The fist setting applies globally, whilst second setting is private and exclusive to the "spring" servlet.

answered Apr 08 '15 at 11:59

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Karan Kaw · Accepted Answer · 2015-04-09T11:47:11.157

contextConfigLocation in context-param gets Loaded, when We start Our Web Container or server
It usually has DAOImpl, Service, Singleton, Datasource Helper Objects etc , those objects We want to be ready before hand so that they can be used

contextConfigLocation in init-param is specific to that DispatcherServlet Only and gets Loaded as soon as Servlet Starts up which may be Lazily loaded i.e on first call to Servlet, if load-on-startup is not a positive value for that servlet.
This means, Beans defined here could be possibly created later. It usually contains Controller Beans etc

Beans defined in context-param ContextXml are visible to Beans defined in init-param ContextXml
But the Beans defined in init-param are not visible to context-param context Beans
So @Controller Bean is usually defined in ChildApplicationContext while @Service is a part of RootApplicationContext
This means @Controller cannot be injected in @Service While as we easily can easily inject @Service Bean in @Controller

So basically we control Visibility (not scope ) of Beans by having different context-config files

score 1 · Answer 3 · answered Apr 08 '15 at 12:08

There are two types of contexts:

Root context (Super)

Own (child) servlet context (Sub)

As generic application contexts, web application contexts are hierarchical. There is a single root context per application, while each servlet in the application (including a dispatcher servlet in the MVC framework) has its own child context.

Spring : Need for the contextConfigLocation?

3 Answers3