Camel Components

Header

Since Camel 1.5

The Header Expression Language allows you to extract values of named headers.

Header Options

The Header language supports the following options which are listed below.

Name Default Java Type Description

trim (advanced)

true

Boolean

Whether to trim the source code to remove leading and trailing whitespaces and line breaks.

resolveResource (advanced)

false

Boolean

Whether a result of the expression that is a String starting with resource: is loaded as a resource and its content becomes the result, e.g. a script that returns resource:file:order.json or resource:classpath:templates/order.json (a name without a scheme is a classpath resource). Off by default; the resource: prefix on the expression text itself is always resolved. Applies to the expression used as a value, not as a predicate.

Example usage

The recipientList EIP can utilize a header:

  • Java

  • XML

  • YAML

from("direct:a").recipientList(header("myHeader"));
<route>
  <from uri="direct:a" />
  <recipientList>
    <header>myHeader</header>
  </recipientList>
</route>
- route:
    from:
      uri: direct:a
      steps:
        - recipientList:
            expression:
              header:
                expression: myHeader

In this case, the list of recipients are contained in the header 'myHeader'.

Dependencies

The Header language is part of camel-core.