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Chapter 103. MVEL Component
MVEL Component 링크 복사링크가 클립보드에 복사되었습니다!
링크 복사링크가 클립보드에 복사되었습니다!
Available as of Camel 2.12
The mvel: component allows you to process a message using an MVEL template. This can be ideal when using Templating to generate responses for requests.
Maven users will need to add the following dependency to their
pom.xml
for this component:
Camel on EAP deployment 링크 복사링크가 클립보드에 복사되었습니다!
링크 복사링크가 클립보드에 복사되었습니다!
This component is supported by the Camel on EAP (Wildfly Camel) framework, which offers a simplified deployment model on the Red Hat JBoss Enterprise Application Platform (JBoss EAP) container. For details of this model, see chapter "Apache Camel on Red Hat JBoss EAP" in "Deploying into a Web Server".
URI format 링크 복사링크가 클립보드에 복사되었습니다!
링크 복사링크가 클립보드에 복사되었습니다!
mvel:templateName[?options]
mvel:templateName[?options]
Where templateName is the classpath-local URI of the template to invoke; or the complete URL of the remote template (eg: file://folder/myfile.mvel).
You can append query options to the URI in the following format,
?option=value&option=value&...
Options 링크 복사링크가 클립보드에 복사되었습니다!
링크 복사링크가 클립보드에 복사되었습니다!
Option | Default | Description |
---|---|---|
contentCache
|
true
|
Cache for the resource content when it is loaded. The cached resource content can be cleared via JMX using the endpoint's clearContentCache operation.
|
encoding
|
null
|
Character encoding of the resource content. |
Message Headers 링크 복사링크가 클립보드에 복사되었습니다!
링크 복사링크가 클립보드에 복사되었습니다!
The mvel component sets a couple headers on the message.
Header | Description |
---|---|
CamelMvelResourceUri
|
The templateName as a String object.
|
MVEL Context 링크 복사링크가 클립보드에 복사되었습니다!
링크 복사링크가 클립보드에 복사되었습니다!
Camel will provide exchange information in the MVEL context (just a
Map
). The Exchange
is transfered as:
key | value |
---|---|
exchange
|
The Exchange itself.
|
exchange.properties
|
The Exchange properties.
|
headers
|
The headers of the In message. |
camelContext
|
The Camel Context intance. |
request
|
The In message. |
in
|
The In message. |
body
|
The In message body. |
out
|
The Out message (only for InOut message exchange pattern). |
response
|
The Out message (only for InOut message exchange pattern). |
Hot reloading 링크 복사링크가 클립보드에 복사되었습니다!
링크 복사링크가 클립보드에 복사되었습니다!
The mvel template resource is, by default, hot reloadable for both file and classpath resources (expanded jar). If you set
contentCache=true
, Camel will only load the resource once, and thus hot reloading is not possible. This scenario can be used in production, when the resource never changes.
Dynamic templates 링크 복사링크가 클립보드에 복사되었습니다!
링크 복사링크가 클립보드에 복사되었습니다!
Camel provides two headers by which you can define a different resource location for a template or the template content itself. If any of these headers is set then Camel uses this over the endpoint configured resource. This allows you to provide a dynamic template at runtime.
Header | Type | Description |
---|---|---|
CamelMvelResourceUri
|
String | A URI for the template resource to use instead of the endpoint configured. |
CamelMvelTemplate
|
String | The template to use instead of the endpoint configured. |
Samples 링크 복사링크가 클립보드에 복사되었습니다!
링크 복사링크가 클립보드에 복사되었습니다!
For example you could use something like
from("activemq:My.Queue"). to("mvel:com/acme/MyResponse.mvel");
from("activemq:My.Queue").
to("mvel:com/acme/MyResponse.mvel");
To use a MVEL template to formulate a response to a message for InOut message exchanges (where there is a
JMSReplyTo
header).
To specify what template the component should use dynamically via a header, so for example:
from("direct:in"). setHeader("CamelMvelResourceUri").constant("path/to/my/template.mvel"). to("mvel:dummy");
from("direct:in").
setHeader("CamelMvelResourceUri").constant("path/to/my/template.mvel").
to("mvel:dummy");
To specify a template directly as a header the component should use dynamically via a header, so for example:
from("direct:in"). setHeader("CamelMvelTemplate").constant("@{\"The result is \" + request.body * 3}\" }"). to("velocity:dummy");
from("direct:in").
setHeader("CamelMvelTemplate").constant("@{\"The result is \" + request.body * 3}\" }").
to("velocity:dummy");