docs/user-manual/modules/ROOT/pages/spring-example.adoc

= Spring Example

The spring example is a simple refactor of the
adoc:walk-through-an-example.adoc[first example] to show how to use the
xref:spring.adoc[Spring] approach to working with Camel. In this example
we just write RouteBuilder implementations, then we write a Spring
ApplicationContext XML file to configure Camel so that it auto-discovers
the routes on the classpath.

To run the example we use the xref:camel-maven-plugin.adoc[Camel Maven
Plugin]. For example from the source or binary distribution the
following should work

[source,shell]
----
cd examples/camel-example-spring
mvn camel:run
----

What this does is boot up the Spring ApplicationContext defined in the
file
https://github.com/apache/camel/blob/master/examples/camel-example-spring/src/main/resources/META-INF/spring/camel-context.xml[META-INF/spring/camel-context.xml]
on the classpath. This is a regular Spring XML document which uses the
Camel link:xml-configuration.html[Xml Configuration] to configure a
link:camelcontext.html[CamelContext]. Notice how the <camelContext>
element is configured

[source,syntaxhighlighter-pre]
----
  <camelContext xmlns="http://activemq.apache.org/camel/schema/spring">
   <package>org.apache.camel.example.spring</package>
     ...
----

The packages attribute defines the comma separated list of Java package
names which are recursively searched for Java classes on the classpath
which implement the xref:route-builder.adoc[RouteBuilder] interface. What
this means is that Camel will automatically detect our
https://github.com/apache/camel/blob/master/examples/camel-example-spring/src/main/java/org/apache/camel/example/spring/MyRouteBuilder.java[MyRouteBuilder
class] and automatically install its routes. Of course, in practice you
should not specify org.apache.camel (or a sub package of this) as the
package name because this will instruct Camel to search in its own
packages for your routes.

This approach, of using Java code to write the routes in the
xref:dsl.adoc[DSL] and just wire together in XML what we really need to
allows us to use the right language for the job and minimise the amount
of XML bloat. Of course if you prefer you can create all of your routes
in the xref:xml-configuration.adoc[Xml Configuration].

Also note at the end of this
https://github.com/apache/camel/blob/master/examples/camel-example-spring/src/main/resources/META-INF/spring/camel-context.xml[XML
example file] we explicitly configure the xref:components::activemq-component.adoc[ActiveMQ]
component with details of how to connect to the broker.