JSON Jackson

Since Camel 2.0

Jackson is a Data Format which uses the Jackson Library

from("activemq:My.Queue").
  marshal().json(JsonLibrary.Jackson).
  to("mqseries:Another.Queue");

Jackson Options

The JSON Jackson dataformat supports 20 options, which are listed below.

Name Default Java Type Description

objectMapper

String

Lookup and use the existing ObjectMapper with the given id when using Jackson.

useDefaultObjectMapper

Boolean

Whether to lookup and use default Jackson ObjectMapper from the registry.

autoDiscoverObjectMapper

Boolean

If set to true then Jackson will look for an objectMapper to use from the registry.

prettyPrint

Boolean

To enable pretty printing output nicely formatted. Is by default false.

unmarshalType

String

Class name of the java type to use when unmarshalling.

jsonView

String

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. This option is to refer to the class which has JsonView annotations.

include

String

If you want to marshal a pojo to JSON, and the pojo has some fields with null values. And you want to skip these null values, you can set this option to NON_NULL.

allowJmsType

Boolean

Used for JMS users to allow the JMSType header from the JMS spec to specify a FQN classname to use to unmarshal to.

collectionType

String

Refers to a custom collection type to lookup in the registry to use. This option should rarely be used, but allows using different collection types than java.util.Collection based as default.

useList

Boolean

To unmarshal to a List of Map or a List of Pojo.

moduleClassNames

String

To use custom Jackson modules com.fasterxml.jackson.databind.Module specified as a String with FQN class names. Multiple classes can be separated by comma.

moduleRefs

String

To use custom Jackson modules referred from the Camel registry. Multiple modules can be separated by comma.

enableFeatures

String

Set of features to enable on the Jackson com.fasterxml.jackson.databind.ObjectMapper. The features should be a name that matches a enum from com.fasterxml.jackson.databind.SerializationFeature, com.fasterxml.jackson.databind.DeserializationFeature, or com.fasterxml.jackson.databind.MapperFeature Multiple features can be separated by comma.

disableFeatures

String

Set of features to disable on the Jackson com.fasterxml.jackson.databind.ObjectMapper. The features should be a name that matches a enum from com.fasterxml.jackson.databind.SerializationFeature, com.fasterxml.jackson.databind.DeserializationFeature, or com.fasterxml.jackson.databind.MapperFeature Multiple features can be separated by comma.

allowUnmarshallType

Boolean

If enabled then Jackson is allowed to attempt to use the CamelJacksonUnmarshalType header during the unmarshalling. This should only be enabled when desired to be used.

timezone

String

If set then Jackson will use the Timezone when marshalling/unmarshalling. This option will have no effect on the others Json DataFormat, like gson, fastjson and xstream.

schemaResolver

String

Optional schema resolver used to lookup schemas for the data in transit.

autoDiscoverSchemaResolver

Boolean

When not disabled, the SchemaResolver will be looked up into the registry.

namingStrategy

String

If set then Jackson will use the the defined Property Naming Strategy.Possible values are: LOWER_CAMEL_CASE, LOWER_DOT_CASE, LOWER_CASE, KEBAB_CASE, SNAKE_CASE and UPPER_CAMEL_CASE.

contentTypeHeader

Boolean

Whether the data format should set the Content-Type header with the type from the data format. For example application/xml for data formats marshalling to XML, or application/json for data formats marshalling to JSON.

Using custom ObjectMapper

You can configure JacksonDataFormat to use a custom ObjectMapper in case you need more control of the mapping configuration.

If you setup a single ObjectMapper in the registry, then Camel will automatic lookup and use this ObjectMapper. For example if you use Spring Boot, then Spring Boot can provide a default ObjectMapper for you if you have Spring MVC enabled. And this would allow Camel to detect that there is one bean of ObjectMapper class type in the Spring Boot bean registry and then use it. When this happens you should set a INFO logging from Camel.

Using Jackson for automatic type conversion

The camel-jackson module allows integrating Jackson as a Type Converter.

This gives a set of out of the box converters to/from the Jackson type JSonNode, such as converting from JSonNode to String or vice-versa.

Enabling more type converters and support for POJOs

To enable POJO conversion support for camel-jackson then this must be enabled, which is done by setting the following options on the CamelContext global options, as shown:

// Enable Jackson JSON type converter for more types.
camelContext.getGlobalOptions().put("CamelJacksonEnableTypeConverter", "true");
// Allow Jackson JSON to convert to pojo types also
// (by default Jackson only converts to String and other simple types)
getContext().getGlobalOptions().put("CamelJacksonTypeConverterToPojo", "true");

The camel-jackson type converter integrates with JAXB which means you can annotate POJO class with JAXB annotations that Jackson can use. You can also use Jacksons own annotations on your POJO classes.

Dependencies

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

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-jackson</artifactId>
  <version>x.x.x</version>
  <!-- use the same version as your Camel core version -->
</dependency>