String Template
The string-template:
component allows you to process a message using a String Template. This can be ideal when using Templating to generate responses for requests.
URI format
Maven users will need to add the following dependency to their pom.xml
for this component:
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URI Format
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Where Where templateName
is the classpath-local URI of the template to invoke; or the complete URL of the remote template.
You can append query options to the URI in the following format, ?option=value&option=value&...
Options
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Option | Default | Description |
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Cache for the resource content when its loaded. | ||
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| From Camel 2.11.1: configuring the variable start delimiter |
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| From Camel 2.11.1: configuring the variable end delimiter |
Headers
Camel will store a reference to the resource in the message header in the with key, org.apache.camel.stringtemplate.resource
. The Resource is an org.springframework.core.io.Resource
object.
Hot
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-Reloading
The stringtemplate string template resource is by default hot-reloadable for both file and classpath resources (expanded jar). Setting the If you set contentCache=true
then , Camel will only load the resource just once, and thus disabling hot-reloading is not possible. This scenario can be used in production usage when the resource never changes.
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StringTemplate Attributes
Camel will provide exchange information in the velocity context as attributes (just a java.util.Map
) to the string template. The Exchange is transfered to the VelocityContext transferred as:
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Key |
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Value | |
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| The Exchange itself. |
| The headers of |
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the | |
| The Camel Context. |
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The |
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The |
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The |
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The |
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for |
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The |
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for |
From Camel 2.14: you can define the custom context map by setting the message header CamelStringTemplateVariableMap
, as shown below:
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Samples
For example you could use something like
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a string template as follows in order to formulate a response to a message:
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The Email Sample
In this sample we want to use StringTemplate as templating for a string template to send an order confirmation email. The email template is laid out in StringTemplate
as:
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This example works for camel 2.11.0. If your camel version is less than 2.11.0, the variables should be started and ended with $
.
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And the java code :
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is as follows:
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