Jackson XML
Available as of Camel 2.16
Jackson XML is a Data Format which uses the Jackson library with the XMLMapper extension to unmarshal an XML payload into Java objects or to marshal Java objects into an XML payload.
Info |
---|
If you are familiar with Jackson, this XML data format behaves in the same way as its JSON counterpart, and thus can be used with classes annotated for JSON serialization/deserialization. This extension also mimics JAXB's "Code first" approach. This data format relies on Woodstox (especially for features like pretty printing), a fast and efficient XML processor. |
Code Block |
---|
from("activemq:My.Queue"). unmarshal().jacksonxml(). to("mqseries:Another.Queue"); |
...
When marshalling a POJO to JSON XML you might want to exclude certain fields from the JSON XML output. With Jackson you can use JSON views to accomplish this. First create one or more marker classes.
Wiki Markup |
---|
{snippet:id=marker|lang=java|url=camel/trunk/components/camel-jacksonxml/src/test/java/org/apache/camel/component/jacksonxml/Views.java} |
@JsonView
annotation to include/exclude certain fields. The annotation also works on getters.Wiki Markup |
---|
{snippet:id=jsonview|lang=java|url=camel/trunk/components/camel-jacksonxml/src/test/java/org/apache/camel/component/jacksonxml/TestPojoView.java} |
JacksonXMLDataFormat
to marshall the above POJO to XML.Wiki Markup |
---|
{snippet:id=format|lang=java|url=camel/trunk/components/camel-jacksonxml/src/test/java/org/apache/camel/component/jacksonxml/JacksonMarshalViewTest.java} |
Code Block |
---|
<pojo age="30" weight="70"/> |
Include/Exclude fields using the jsonView
attribute with JacksonXML
DataFormat
As an example of using this attribute you can instead of:
Code Block | ||
---|---|---|
| ||
JacksonXMLDataFormat ageViewFormat = new JacksonXMLDataFormat(TestPojoView.class, Views.Age.class);
from("direct:inPojoAgeView").
marshal(ageViewFormat);
|
Directly specify your JSON view inside the Java DSL as:
Code Block | ||
---|---|---|
| ||
from("direct:inPojoAgeView").
marshal().jacksonxml(TestPojoView.class, Views.Age.class);
|
And the same in XML DSL:
Code Block | ||
---|---|---|
| ||
<from uri="direct:inPojoAgeView"/>
<marshal>
<jacksonxml unmarshalTypeName="org.apache.camel.component.jacksonxml.TestPojoView" jsonView="org.apache.camel.component.jacksonxml.Views$Age"/>
</marshal>
|
Setting serialization include option
If you want to marshal a pojo to XML, and the pojo has some fields with null values. And you want to skip these null values, then you need to set either an annotation on the pojo,
Code Block |
---|
@JsonInclude(Include.NON_NULL) public class MyPojo {"age":30, "weight":70} ... } |
But this requires you to include that annotation in your pojo source code. You can also configure the Camel JacksonXMLDataFormat to set the include option, as shown below:
Code Block |
---|
JacksonXMLDataFormat format = new JacksonXMLDataFormat();
format.setInclude("NON_NULL"); |
Or from XML DSL you configure this as
Code Block |
---|
<dataFormats>
<jacksonxml id="jacksonxml" include="NOT_NULL"/>
</dataFormats> |
Unmarshalling from XML to POJO with dynamic class name
If you use jackson to unmarshal XML to POJO, then you can now specify a header in the message that indicate which class name to unmarshal to.
The header has key CamelJacksonUnmarshalType
if that header is present in the message, then Jackson will use that as FQN for the POJO class to unmarshal the XML payload as.
For JMS end users there is the JMSType header from the JMS spec that indicates that also. To enable support for JMSType you would need to turn that on, on the jackson data format as shown:
Code Block |
---|
JacksonDataFormat format = new JacksonDataFormat();
format.setAllowJmsType(true); |
Or from XML DSL you configure this as
Code Block |
---|
<dataFormats>
<jacksonxml id="jacksonxml" allowJmsType="true"/>
</dataFormats> |
Unmarshalling from XML to List<Map> or List<pojo>
If you are using Jackson to unmarshal XML to a list of map/pojo, you can now specify this by setting useList="true"
or use the org.apache.camel.component.jacksonxml.ListJacksonXMLDataFormat
. For example with Java you can do as shown below:
Code Block |
---|
JacksonXMLDataFormat format = new ListJacksonXMLDataFormat();
// or
JacksonXMLDataFormat format = new JacksonXMLDataFormat();
format.useList();
// and you can specify the pojo class type also
format.setUnmarshalType(MyPojo.class); |
And if you use XML DSL then you configure to use list using useList
attribute as shown below:
Code Block |
---|
<dataFormats>
<jacksonxml id="jack" useList="true"/>
</dataFormats> |
And you can specify the pojo type also
Code Block |
---|
<dataFormats>
<jacksonxml id="jack" useList="true" unmarshalTypeName="com.foo.MyPojo"/>
</dataFormats> |
Using custom Jackson modules
You can use custom Jackson modules by specifying the class names of those using the moduleClassNames option as shown below.
Code Block |
---|
<dataFormats>
<jacksonxml id="jack" useList="true" unmarshalTypeName="com.foo.MyPojo" moduleClassNames="com.foo.MyModule,com.foo.MyOtherModule"/>
</dataFormats> |
When using moduleClassNames then the custom jackson modules are not configured, by created using default constructor and used as-is. If a custom module needs any custom configuration, then an instance of the module can be created and configured, and then use modulesRefs to refer to the module as shown below:
Code Block |
---|
<bean id="myJacksonModule" class="com.foo.MyModule">
... // configure the module as you want
</bean>
<dataFormats>
<jacksonxml id="jacksonxml" useList="true" unmarshalTypeName="com.foo.MyPojo" moduleRefs="myJacksonModule"/>
</dataFormats> |
Multiple modules can be specified separated by comma, such as moduleRefs="myJacksonModule,myOtherModule"
Enabling or disable features using Jackson
Jackson has a number of features you can enable or disable, which its ObjectMapper uses. For example to disable failing on unknown properties when marshalling, you can configure this using the disableFeatures:
Code Block |
---|
<dataFormats>
<jacksonxml id="jacksonxml" unmarshalTypeName="com.foo.MyPojo" disableFeatures="FAIL_ON_UNKNOWN_PROPERTIES"/>
</dataFormats> |
You can disable multiple features by separating the values using comma. The values for the features must be the name of the enums from Jackson from the following enum classes
- com.fasterxml.jackson.databind.SerializationFeature
- com.fasterxml.jackson.databind.DeserializationFeature
- com.fasterxml.jackson.databind.MapperFeature
To enable a feature use the enableFeatures options instead.
From Java code you can use the type safe methods from camel-jackson module:
Code Block | ||
---|---|---|
| ||
JacksonDataFormat df = new JacksonDataFormat(MyPojo.class);
df.disableFeature(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
df.disableFeature(DeserializationFeature.FAIL_ON_NULL_FOR_PRIMITIVES); |
Converting Maps to POJO using Jackson
Jackson ObjectMapper
can be used to convert maps to POJO objects. Jackson component comes with the data converter that can be used to convert java.util.Map
instance to non-String, non-primitive and non-Number objects.
Code Block | ||
---|---|---|
| ||
Map<String, Object> invoiceData = new HashMap<String, Object>();
invoiceData.put("netValue", 500);
producerTemplate.sendBody("direct:mapToInvoice", invoiceData);
...
// Later in the processor
Invoice invoice = exchange.getIn().getBody(Invoice.class); |
If there is a single ObjectMapper
instance available in the Camel registry, it will used by the converter to perform the conversion. Otherwise the default mapper will be used.
Formatted XML marshalling (pretty-printing)
Using the prettyPrint
option one can output a well formatted XML while marshalling:
Code Block |
---|
<dataFormats>
<jacksonxml id="jack" prettyPrint="true"/>
</dataFormats> |
And in Java DSL:
Code Block |
---|
from("direct:inPretty").marshal().jacksonxml(true); |
Please note that there are 5 different overloaded jacksonxml()
DSL methods which support the prettyPrint
option in combination with other settings for unmarshalType
, jsonView
etc.
Dependencies
To use Jackson XML in your camel routes you need to add the dependency on camel-jacksonxml which implements this data format.
...