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By default Camel uses the XStream library.

Using

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Json data format with the XStream library

// lets turn Object messages into json then send to MQSeries
from("activemq:My.Queue").
  marshal().json().
  to("mqseries:Another.Queue");

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       <route>
            <from uri="direct:back"/>
            <unmarshal ref="jack"/>
            <to uri="mock:reverse"/>
        </route>

Excluding POJO fields from marshalling

When marshalling a POJO to JSON you might want to exclude certain fields from the JSON output. With Jackson you can use JSON views to accomplish this. First create one or more marker classes.

{snippet:id=marker|lang=java|url=camel/trunk/components/camel-jackson/src/test/java/org/apache/camel/component/jackson/Views.java}

Use the marker classes with the @JsonView annotation to include/exclude certain fields. The annotation also works on getters.

{snippet:id=jsonview|lang=java|url=camel/trunk/components/camel-jackson/src/test/java/org/apache/camel/component/jackson/TestPojoView.java}

Finally use the Camel JacksonDataFormat to marshall the above POJO to JSON.

{snippet:id=format|lang=java|url=camel/trunk/components/camel-jackson/src/test/java/org/apache/camel/component/jackson/JacksonMarshalViewTest.java}

Note that the weight field in missing in the resulting JSON:

{"age":30, "height":190}

The GSON library supports a similar feature through the notion of ExclusionStrategies:

{snippet:id=strategy|lang=java|url=camel/trunk/components/camel-gson/src/test/java/org/apache/camel/component/gson/GsonMarshalExclusionTest.java}

The GsonDataFormat accepts an ExclusionStrategy in its constructor:

{snippet:id=format|lang=java|url=camel/trunk/components/camel-gson/src/test/java/org/apache/camel/component/gson/GsonMarshalExclusionTest.java}

The line above will exclude fields annotated with @ExcludeAge during JSON marshalling.

Dependencies for XStream

To use JSON in your camel routes you need to add the a dependency on camel-xstream which implements this data format.

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