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Understanding
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Spring
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Contexts
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in
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ES
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Web
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Apps
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The
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Spring
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configuration
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in
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ES
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web
...
apps
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is
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a little complicated,
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and
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involves
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many
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XML
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files.
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This
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is
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an
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attempt
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to
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document
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how
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the
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config
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files
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work
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together.
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In
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a
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typical
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ES
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web
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app,
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Spring
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is
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bootstrapped
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from
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the
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web.xml
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file.
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There
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are
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two
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Spring
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contexts
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initialized
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via
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web.xml:
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The
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"root"
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application
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context.
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There
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is
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a
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single
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"root"
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application
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context
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that
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applies
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to
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all
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servlets
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in
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the
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web
...
app
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(a
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web
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app
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can
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contain
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multiple
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servlets,
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although
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the
...
typical
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ES
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web
...
app
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only
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has
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one
...
servlet).
...
The
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root
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context
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contains
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middle-tier
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services,
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data
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sources
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etc.
...
The
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root
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context
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is
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configured
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via
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the
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ContextLoaderListener
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(defined
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in
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the
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<listeners>
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section)
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and
...
the
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contextConfigLocation
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parameter
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(defined
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in
...
the
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<context-param>
...
section):
| Code Block |
|---|
{code} <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> <context-param> <param-name>contextConfigLocation</param-name> <param-value> classpath*:applicationContext-common.xml, classpath*:applicationContext-onlinereg-email.xml, classpath*:applicationContext.xml, classpath*:applicationContext-onlinereg-security.xml, classpath*:applicationContext-web.xml, classpath*:applicationContext-container.xml </param-value> </context-param> {code} h2. The |
The "servlet"
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application
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Context
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Each
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servlet
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in
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the
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web
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app
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can
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have
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its
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own
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application
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context.
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These
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application
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contexts
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inherit
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all
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the
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beans
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defined
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in
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the
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root
...
context.
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According
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to
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the
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Spring
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docs,
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the
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servlet
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context
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can
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override
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bean
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definitions
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from
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the
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root
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context.
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Typically,
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web-specific
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configuration
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(i.e.
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Spring
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MVC)
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is
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placed
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in
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the
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servlet
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context.
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The
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servlet
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contexts
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are
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configured
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via
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a
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DispatcherServlet
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in
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the
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<servlet>
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section:
| Code Block |
|---|
{code} <servlet> <servlet-name>onlinereg</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:servlet.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> {code} |
The
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default
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name
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for
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the
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servlet
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context's
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XML
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file
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is
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[SAISFRAMEWORK:servlet-name
...
]-servlet.xml
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.
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In
...
the
...
ES
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web
...
apps,
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where
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there
...
is
...
only
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one
...
servlet,
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we
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tend
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to
...
name
...
this
...
file
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servlet.xml
...
.