JAXB

Since Camel 1.0

JAXB is a Data Format which uses the JAXB2 XML marshalling standard which is included in Java 6 to unmarshal an XML payload into Java objects or to marshal Java objects into an XML payload.

Options

The JAXB dataformat supports 18 options, which are listed below.

Name Default Java Type Description

contextPath

String

Package name where your JAXB classes are located.

schema

String

To validate against an existing schema. Your can use the prefix classpath:, file: or http: to specify how the resource should by resolved. You can separate multiple schema files by using the ',' character.

schemaSeverityLevel

0

Integer

Sets the schema severity level to use when validating against a schema. This level determines the minimum severity error that triggers JAXB to stop continue parsing. The default value of 0 (warning) means that any error (warning, error or fatal error) will trigger JAXB to stop. There are the following three levels: 0=warning, 1=error, 2=fatal error. The value can be one of: 0, 1, 2

prettyPrint

false

Boolean

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

objectFactory

false

Boolean

Whether to allow using ObjectFactory classes to create the POJO classes during marshalling. This only applies to POJO classes that has not been annotated with JAXB and providing jaxb.index descriptor files.

ignoreJAXBElement

false

Boolean

Whether to ignore JAXBElement elements - only needed to be set to false in very special use-cases.

mustBeJAXBElement

false

Boolean

Whether marhsalling must be java objects with JAXB annotations. And if not then it fails. This option can be set to false to relax that, such as when the data is already in XML format.

filterNonXmlChars

false

Boolean

To ignore non xml characheters and replace them with an empty space.

encoding

String

To overrule and use a specific encoding

fragment

false

Boolean

To turn on marshalling XML fragment trees. By default JAXB looks for XmlRootElement annotation on given class to operate on whole XML tree. This is useful but not always - sometimes generated code does not have XmlRootElement annotation, sometimes you need unmarshall only part of tree. In that case you can use partial unmarshalling. To enable this behaviours you need set property partClass. Camel will pass this class to JAXB’s unmarshaler.

partClass

String

Name of class used for fragment parsing. See more details at the fragment option.

partNamespace

String

XML namespace to use for fragment parsing. See more details at the fragment option.

namespacePrefixRef

String

When marshalling using JAXB or SOAP then the JAXB implementation will automatic assign namespace prefixes, such as ns2, ns3, ns4 etc. To control this mapping, Camel allows you to refer to a map which contains the desired mapping.

xmlStreamWriterWrapper

String

To use a custom xml stream writer.

schemaLocation

String

To define the location of the schema

noNamespaceSchemaLocation

String

To define the location of the namespaceless schema

jaxbProviderProperties

String

Refers to a custom java.util.Map to lookup in the registry containing custom JAXB provider properties to be used with the JAXB marshaller.

contentTypeHeader

false

Boolean

Whether the data format should set the Content-Type header with the type from the data format if the data format is capable of doing so. For example application/xml for data formats marshalling to XML, or application/json for data formats marshalling to JSon etc.

Using the Java DSL

For example the following uses a named DataFormat of jaxb which is configured with a number of Java package names to initialize the JAXBContext.

DataFormat jaxb = new JaxbDataFormat("com.acme.model");

from("activemq:My.Queue").
  unmarshal(jaxb).
  to("mqseries:Another.Queue");

You can if you prefer use a named reference to a data format which can then be defined in your Registry such as via your Spring XML file. e.g.

from("activemq:My.Queue").
  unmarshal("myJaxbDataType").
  to("mqseries:Another.Queue");

Using Spring XML

The following example shows how to use JAXB to unmarshal using Spring configuring the jaxb data type

This example shows how to configure the data type just once and reuse it on multiple routes.

Multiple context paths

It is possible to use this data format with more than one context path. You can specify context path using : as separator, for example com.mycompany:com.mycompany2. Note that this is handled by JAXB implementation and might change if you use different vendor than RI.

Partial marshalling/unmarshalling

 JAXB 2 supports marshalling and unmarshalling XML tree fragments. By
default JAXB looks for `@XmlRootElement` annotation on given class to
operate on whole XML tree. This is useful but not always - sometimes
generated code does not have @XmlRootElement annotation, sometimes you
need unmarshall only part of tree. +
 In that case you can use partial unmarshalling. To enable this
behaviours you need set property `partClass`. Camel will pass this class
to JAXB's unmarshaler. If `JaxbConstants.JAXB_PART_CLASS` is set as
one of headers, (even if partClass property is set on DataFormat), the property
on DataFormat is surpassed and the one set in the headers is used.

For marshalling you have to add partNamespace attribute with QName of destination namespace. Example of Spring DSL you can find above. If JaxbConstants.JAXB_PART_NAMESPACE is set as one of headers, (even if partNamespace property is set on DataFormat), the property on DataFormat is surpassed and the one set in the headers is used. While setting partNamespace through JaxbConstants.JAXB_PART_NAMESPACE, please note that you need to specify its value {[namespaceUri]}[localPart]

   ...
   .setHeader(JaxbConstants.JAXB_PART_NAMESPACE, simple("{http://www.camel.apache.org/jaxb/example/address/1}address"));
   ...

Fragment

 JaxbDataFormat has new property fragment which can set the the
`Marshaller.JAXB_FRAGMENT` encoding property on the JAXB Marshaller. If
you don't want the JAXB Marshaller to generate the XML declaration, you
can set this option to be true. The default value of this property is
false.

Ignoring the NonXML Character

 JaxbDataFormat supports to ignore the
http://www.w3.org/TR/2004/REC-xml-20040204/#NT-Char[NonXML Character],
you just need to set the filterNonXmlChars property to be true,
JaxbDataFormat will replace the NonXML character with " " when it is
marshaling or unmarshaling the message. You can also do it by setting
the Exchange property
`Exchange.FILTER_NON_XML_CHARS`.
JDK 1.5 JDK 1.6+

Filtering in use

StAX API and implementation

No

Filtering not in use

StAX API only

No

This feature has been tested with Woodstox 3.2.9 and Sun JDK 1.6 StAX implementation.

 JaxbDataFormat now allows you to customize the XMLStreamWriter used to
marshal the stream to XML. Using this configuration, you can add your
own stream writer to completely remove, escape, or replace non-xml
characters.
   JaxbDataFormat customWriterFormat = new JaxbDataFormat("org.apache.camel.foo.bar");
  customWriterFormat.setXmlStreamWriterWrapper(new TestXmlStreamWriter());

The following example shows using the Spring DSL and also enabling Camel’s NonXML filtering:

<bean id="testXmlStreamWriterWrapper" class="org.apache.camel.jaxb.TestXmlStreamWriter"/>
<jaxb filterNonXmlChars="true"  contextPath="org.apache.camel.foo.bar" xmlStreamWriterWrapper="#testXmlStreamWriterWrapper" />

Working with the ObjectFactory

If you use XJC to create the java class from the schema, you will get an ObjectFactory for you JAXB context. Since the ObjectFactory uses JAXBElement to hold the reference of the schema and element instance value, jaxbDataformat will ignore the JAXBElement by default and you will get the element instance value instead of the JAXBElement object form the unmarshaled message body.
If you want to get the JAXBElement object form the unmarshaled message body, you need to set the JaxbDataFormat object’s ignoreJAXBElement property to be false.

Setting encoding

You can set the encoding option to use when marshalling. Its the Marshaller.JAXB_ENCODING encoding property on the JAXB Marshaller.
You can setup which encoding to use when you declare the JAXB data format. You can also provide the encoding in the Exchange property Exchange.CHARSET_NAME. This property will overrule the encoding set on the JAXB data format.

In this Spring DSL we have defined to use iso-8859-1 as the encoding:

Controlling namespace prefix mapping

Since Camel 2.11

When marshalling using JAXB or SOAP then the JAXB implementation will automatic assign namespace prefixes, such as ns2, ns3, ns4 etc. To control this mapping, Camel allows you to refer to a map which contains the desired mapping.

Notice this requires having JAXB-RI 2.1 or better (from SUN) on the classpath, as the mapping functionality is dependent on the implementation of JAXB, whether its supported.

For example in Spring XML we can define a Map with the mapping. In the mapping file below, we map SOAP to use soap as prefix. While our custom namespace "http://www.mycompany.com/foo/2" is not using any prefix.

  <util:map id="myMap">
    <entry key="http://www.w3.org/2003/05/soap-envelope" value="soap"/>
    <!-- we dont want any prefix for our namespace -->
    <entry key="http://www.mycompany.com/foo/2" value=""/>
  </util:map>

To use this in JAXB or SOAP you refer to this map, using the namespacePrefixRef attribute as shown below. Then Camel will lookup in the Registry a java.util.Map with the id "myMap", which was what we defined above.

  <marshal>
    <soapjaxb version="1.2" contextPath="com.mycompany.foo" namespacePrefixRef="myMap"/>
  </marshal>

Schema validation

Since Camel 2.11

The JAXB Data Format supports validation by marshalling and unmarshalling from/to XML. Your can use the prefix classpath:, file: or http: to specify how the resource should by resolved. You can separate multiple schema files by using the ',' character.

Using the Java DSL, you can configure it in the following way:

JaxbDataFormat jaxbDataFormat = new JaxbDataFormat();
jaxbDataFormat.setContextPath(Person.class.getPackage().getName());
jaxbDataFormat.setSchema("classpath:person.xsd,classpath:address.xsd");

You can do the same using the XML DSL:

<marshal>
    <jaxb id="jaxb" schema="classpath:person.xsd,classpath:address.xsd"/>
</marshal>

Camel will create and pool the underling SchemaFactory instances on the fly, because the SchemaFactory shipped with the JDK is not thread safe.
However, if you have a SchemaFactory implementation which is thread safe, you can configure the JAXB data format to use this one:

JaxbDataFormat jaxbDataFormat = new JaxbDataFormat();
jaxbDataFormat.setSchemaFactory(thradSafeSchemaFactory);

Schema Location

Since Camel 2.14

The JAXB Data Format supports to specify the SchemaLocation when marshaling the XML.

Using the Java DSL, you can configure it in the following way:

JaxbDataFormat jaxbDataFormat = new JaxbDataFormat();
jaxbDataFormat.setContextPath(Person.class.getPackage().getName());
jaxbDataFormat.setSchemaLocation("schema/person.xsd");

You can do the same using the XML DSL:

<marshal>
    <jaxb id="jaxb" schemaLocation="schema/person.xsd"/>
</marshal>

Marshal data that is already XML

Since Camel 2.14.1

The JAXB marshaller requires that the message body is JAXB compatible, eg its a JAXBElement, eg a java instance that has JAXB annotations, or extend JAXBElement. There can be situations where the message body is already in XML, eg from a String type. There is a new option mustBeJAXBElement you can set to false, to relax this check, so the JAXB marshaller only attempts to marshal JAXBElements (javax.xml.bind.JAXBIntrospector#isElement returns true). And in those situations the marshaller fallbacks to marshal the message body as-is.

Dependencies

To use JAXB in your camel routes you need to add the a dependency on camel-jaxb 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-jaxb</artifactId>
  <version>x.x.x</version>
</dependency>

Spring Boot Auto-Configuration

When using jaxb with Spring Boot make sure to use the following Maven dependency to have support for auto configuration:

<dependency>
  <groupId>org.apache.camel.springboot</groupId>
  <artifactId>camel-jaxb-starter</artifactId>
  <version>x.x.x</version>
  <!-- use the same version as your Camel core version -->
</dependency>

The component supports 20 options, which are listed below.

Name Description Default Type

camel.dataformat.jaxb.content-type-header

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

false

Boolean

camel.dataformat.jaxb.context-path

Package name where your JAXB classes are located.

String

camel.dataformat.jaxb.context-path-is-class-name

This can be set to true to mark that the contextPath is referring to a classname and not a package name.

false

Boolean

camel.dataformat.jaxb.enabled

Whether to enable auto configuration of the jaxb data format. This is enabled by default.

Boolean

camel.dataformat.jaxb.encoding

To overrule and use a specific encoding

String

camel.dataformat.jaxb.filter-non-xml-chars

To ignore non xml characheters and replace them with an empty space.

false

Boolean

camel.dataformat.jaxb.fragment

To turn on marshalling XML fragment trees. By default JAXB looks for XmlRootElement annotation on given class to operate on whole XML tree. This is useful but not always - sometimes generated code does not have XmlRootElement annotation, sometimes you need unmarshall only part of tree. In that case you can use partial unmarshalling. To enable this behaviours you need set property partClass. Camel will pass this class to JAXB’s unmarshaler.

false

Boolean

camel.dataformat.jaxb.ignore-j-a-x-b-element

Whether to ignore JAXBElement elements - only needed to be set to false in very special use-cases.

false

Boolean

camel.dataformat.jaxb.jaxb-provider-properties

Refers to a custom java.util.Map to lookup in the registry containing custom JAXB provider properties to be used with the JAXB marshaller.

String

camel.dataformat.jaxb.must-be-j-a-x-b-element

Whether marhsalling must be java objects with JAXB annotations. And if not then it fails. This option can be set to false to relax that, such as when the data is already in XML format.

false

Boolean

camel.dataformat.jaxb.namespace-prefix-ref

When marshalling using JAXB or SOAP then the JAXB implementation will automatic assign namespace prefixes, such as ns2, ns3, ns4 etc. To control this mapping, Camel allows you to refer to a map which contains the desired mapping.

String

camel.dataformat.jaxb.no-namespace-schema-location

To define the location of the namespaceless schema

String

camel.dataformat.jaxb.object-factory

Whether to allow using ObjectFactory classes to create the POJO classes during marshalling. This only applies to POJO classes that has not been annotated with JAXB and providing jaxb.index descriptor files.

false

Boolean

camel.dataformat.jaxb.part-class

Name of class used for fragment parsing. See more details at the fragment option.

String

camel.dataformat.jaxb.part-namespace

XML namespace to use for fragment parsing. See more details at the fragment option.

String

camel.dataformat.jaxb.pretty-print

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

false

Boolean

camel.dataformat.jaxb.schema

To validate against an existing schema. Your can use the prefix classpath:, file: or http: to specify how the resource should by resolved. You can separate multiple schema files by using the ',' character.

String

camel.dataformat.jaxb.schema-location

To define the location of the schema

String

camel.dataformat.jaxb.schema-severity-level

Sets the schema severity level to use when validating against a schema. This level determines the minimum severity error that triggers JAXB to stop continue parsing. The default value of 0 (warning) means that any error (warning, error or fatal error) will trigger JAXB to stop. There are the following three levels: 0=warning, 1=error, 2=fatal error.

0

Integer

camel.dataformat.jaxb.xml-stream-writer-wrapper

To use a custom xml stream writer.

String