JXPath
Camel supports JXPath to allow XPath expressions to be used on beans in an _expression_ or Predicate to be used in the DSL or Xml Configuration. For example you could use JXPath to create an Predicate in a Message Filter or as an _expression_ for a Recipient List.
You can use XPath expressions directly using smart completion in your IDE as follows
from("queue:foo").filter().
jxpath("/in/body/foo").
to("queue:bar")
Variables
| Variable |
Type |
Description |
| this |
Exchange |
the Exchange object |
| in |
Message |
the exchange.in message |
| out |
Message |
the exchange.out message |
Options
| Option |
Type |
Description |
| lenient |
boolean |
Camel 2.11/2.10.5: Allows to turn lenient on the JXPathContext. When turned on this allows the JXPath _expression_ to evaluate against expressions and message bodies which may be invalid / missing data. See more details at the JXPath Documentation This option is by default false. |
Using XML configuration
If you prefer to configure your routes in your Spring XML file then you can use JXPath expressions as follows
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://camel.apache.org/schema/spring http://camel.apache.org/schema/spring/camel-spring.xsd">
<camelContext id="camel" xmlns="http://activemq.apache.org/camel/schema/spring">
<route>
<from uri="activemq:MyQueue"/>
<filter>
<jxpath>in/body/name = 'James'</xpath>
<to uri="mqseries:SomeOtherQueue"/>
</filter>
</route>
</camelContext>
</beans>
Examples
Here is a simple example using a JXPath _expression_ as a predicate in a Message Filter
from("direct:start").
filter().jxpath("in/body/name='James'").
to("mock:result");
JXPath injection
You can use Bean Integration to invoke a method on a bean and use various languages such as JXPath to extract a value from the message and bind it to a method parameter.
For example
public class Foo {
@MessageDriven(uri = "activemq:my.queue")
public void doSomething(@JXPath("in/body/foo") String correlationID, @Body String body) {
}
}
Loading script from external resource
Available as of Camel 2.11
You can externalize the script and have Camel load it from a resource such as "classpath:", "file:", or "http:".
This is done using the following syntax: "resource:scheme:location", eg to refer to a file on the classpath you can do:
.setHeader("myHeader").jxpath("resource:classpath:myjxpath.txt")
Dependencies
To use JXpath in your camel routes you need to add the a dependency on camel-jxpath which implements the JXpath language.
If you use maven you could just add the following to your pom.xml, substituting the version number for the latest & greatest release (see the download page for the latest versions).
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-jxpath</artifactId>
<version>x.x.x</version>
</dependency>
Otherwise, you'll also need Commons JXPath.
