Chapter 44. JAXB Since Camel 1.0 JAXB is a Data Format which uses the JAXB XML marshalling standard to unmarshal an XML payload into Java objects or to marshal Java objects into an XML payload. 44.1. Dependencies When using jaxb with Red Hat build of Camel 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> </dependency> 44.2. Options The JAXB dataformat supports 20 options, which are listed below. Name Default Java Type Description contextPath String Required Package name where your JAXB classes are located. contextPathIsClassName false Boolean This can be set to true to mark that the contextPath is referring to a classname and not a package name. schema String To validate against an existing schema. Your can use the prefix classpath:, file: or http: to specify how the resource should be resolved. You can separate multiple schema files by using the ',' character. schemaSeverityLevel 0 Enum 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. Enum values: 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 true 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. accessExternalSchemaProtocols false String Only in use if schema validation has been enabled. Restrict access to the protocols specified for external reference set by the schemaLocation attribute, Import and Include element. Examples of protocols are file, http, jar:file. false or none to deny all access to external references; a specific protocol, such as file, to give permission to only the protocol; the keyword all to grant permission to all protocols. 44.3. Using the Java DSL The following example uses a named DataFormat of jaxb which is configured with a Java package name to initialize the JAXBContext . DataFormat jaxb = new JaxbDataFormat("com.acme.model"); from("activemq:My.Queue"). unmarshal(jaxb). to("mqseries:Another.Queue"); You can use a named reference to a data format which can then be defined in your Registry such as via your Spring XML file. from("activemq:My.Queue"). unmarshal("myJaxbDataType"). to("mqseries:Another.Queue"); 44.4. Using Spring XML The following example shows how to configure the JaxbDataFormat and use it in multiple routes. <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"> <bean id="myJaxb" class="org.apache.camel.converter.jaxb.JaxbDataFormat"> <property name="contextPath" value="org.apache.camel.example"/> </bean> <camelContext xmlns="http://camel.apache.org/schema/spring"> <route> <from uri="direct:start"/> <marshal><custom ref="myJaxb"/></marshal> <to uri="direct:marshalled"/> </route> <route> <from uri="direct:marshalled"/> <unmarshal><custom ref="myJaxb"/></unmarshal> <to uri="mock:result"/> </route> </camelContext> </beans> 44.5. Multiple context paths It is possible to use this data format with more than one context path. You can specify multiple context paths using : as a separator, for example com.mycompany:com.mycompany2 . 44.6. Partial marshalling / unmarshalling JAXB 2 supports marshalling and unmarshalling XML tree fragments. By default JAXB looks for the @XmlRootElement annotation on a given class to operate on whole XML tree. Sometimes the generated code does not have the @XmlRootElement annotation and sometimes you need to unmarshall only part of the tree. In that case you can use partial unmarshalling. To enable this behaviour you need set property partClass on the JaxbDataFormat . Camel will pass this class to the JAXB unmarshaller. If JaxbConstants.JAXB_PART_CLASS is set as one of the exchange headers, its value is used to override the partClass property on the JaxbDataFormat . For marshalling you have to add the partNamespace attribute with the QName of the destination namespace. If JaxbConstants.JAXB_PART_NAMESPACE is set as one of the exchange headers, its value is used to override the partNamespace property on the JaxbDataFormat . While setting partNamespace through JaxbConstants.JAXB_PART_NAMESPACE , please note that you need to specify its value in the format {namespaceUri}localPart , as per the example below. .setHeader(JaxbConstants.JAXB_PART_NAMESPACE, constant("{http://www.camel.apache.org/jaxb/example/address/1}address")); 44.7. Fragment JaxbDataFormat has a property named fragment which can set the Marshaller.JAXB_FRAGMENT 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 . 44.8. Ignoring Non-XML Characters JaxbDataFormat supports ignoring Non-XML Characters . Set the filterNonXmlChars property to true . The JaxbDataFormat will replace any non-XML character with a space character ( " " ) during message marshalling or unmarshalling. You can also set 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 non-XML filtering: <bean id="testXmlStreamWriterWrapper" class="org.apache.camel.jaxb.TestXmlStreamWriter"/> <jaxb filterNonXmlChars="true" contextPath="org.apache.camel.foo.bar" xmlStreamWriterWrapper="#testXmlStreamWriterWrapper" /> 44.9. Working with the ObjectFactory If you use XJC to create the java class from the schema, you will get an ObjectFactory for your JAXB context. Since the ObjectFactory uses the 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 from the unmarshaled message body. If you want to get the JAXBElement object form the unmarshaled message body, you need to set the JaxbDataFormat ignoreJAXBElement property to be false . 44.10. Setting the encoding You can set the encoding option on the JaxbDataFormat to configure the Marshaller.JAXB_ENCODING encoding property on the JAXB Marshaller. You can setup which encoding to use when you declare the JaxbDataFormat . You can also provide the encoding in the Exchange property Exchange.CHARSET_NAME . This property will override the encoding set on the JaxbDataFormat . 44.11. Controlling namespace prefix mapping 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. 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 as a 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 don't want any prefix for our namespace --> <entry key="http://www.mycompany.com/foo/2" value=""/> </util:map> To use this in JAXB or SOAP data formats 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> <soap version="1.2" contextPath="com.mycompany.foo" namespacePrefixRef="myMap"/> </marshal> 44.12. Schema validation The JaxbDataFormat supports validation by marshalling and unmarshalling from / to XML. You can use the prefix classpath: , file: or http: to specify how the resource should be resolved. You can separate multiple schema files by using the , character. Note If the XSD schema files import/access other files, then you need to enable file protocol (or others to allow access). 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"); jaxbDataFormat.setAccessExternalSchemaProtocols("file"); You can do the same using the XML DSL: <marshal> <jaxb id="jaxb" schema="classpath:person.xsd,classpath:address.xsd" accessExternalSchemaProtocols="file"/> </marshal> 44.13. Schema Location The JaxbDataFormat supports to specify the SchemaLocation when marshalling 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> 44.14. Marshal data that is already XML The JAXB marshaller requires that the message body is JAXB compatible, e.g it is a JAXBElement , a java instance that has JAXB annotations, or extends JAXBElement . There can be situations where the message body is already in XML, e.g from a String type. JaxbDataFormat has an option named mustBeJAXBElement which you can set to false to relax this check and have the JAXB marshaller only attempt marshalling on JAXBElement ( javax.xml.bind.JAXBIntrospector#isElement returns true ). In those situations the marshaller will fallback to marshal the message body as-is. 44.15. Spring Boot Auto-Configuration The component supports 21 options, which are listed below. Name Description Default Type camel.dataformat.jaxb.access-external-schema-protocols Only in use if schema validation has been enabled. Restrict access to the protocols specified for external reference set by the schemaLocation attribute, Import and Include element. Examples of protocols are file, http, jar:file. false or none to deny all access to external references; a specific protocol, such as file, to give permission to only the protocol; the keyword all to grant permission to all protocols. false String camel.dataformat.jaxb.content-type-header 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. true 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 be 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

Commands:
<dependency> <groupId>org.apache.camel.springboot</groupId> <artifactId>camel-jaxb-starter</artifactId> </dependency>
DataFormat jaxb = new JaxbDataFormat("com.acme.model"); from("activemq:My.Queue"). unmarshal(jaxb). to("mqseries:Another.Queue");
from("activemq:My.Queue"). unmarshal("myJaxbDataType"). to("mqseries:Another.Queue");
<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"> <bean id="myJaxb" class="org.apache.camel.converter.jaxb.JaxbDataFormat"> <property name="contextPath" value="org.apache.camel.example"/> </bean> <camelContext xmlns="http://camel.apache.org/schema/spring"> <route> <from uri="direct:start"/> <marshal><custom ref="myJaxb"/></marshal> <to uri="direct:marshalled"/> </route> <route> <from uri="direct:marshalled"/> <unmarshal><custom ref="myJaxb"/></unmarshal> <to uri="mock:result"/> </route> </camelContext> </beans>
.setHeader(JaxbConstants.JAXB_PART_NAMESPACE, constant("{http://www.camel.apache.org/jaxb/example/address/1}address"));
JaxbDataFormat customWriterFormat = new JaxbDataFormat("org.apache.camel.foo.bar"); customWriterFormat.setXmlStreamWriterWrapper(new TestXmlStreamWriter());
<bean id="testXmlStreamWriterWrapper" class="org.apache.camel.jaxb.TestXmlStreamWriter"/> <jaxb filterNonXmlChars="true" contextPath="org.apache.camel.foo.bar" xmlStreamWriterWrapper="#testXmlStreamWriterWrapper" />
<util:map id="myMap"> <entry key="http://www.w3.org/2003/05/soap-envelope" value="soap"/> <!-- we don't want any prefix for our namespace --> <entry key="http://www.mycompany.com/foo/2" value=""/> </util:map>
<marshal> <soap version="1.2" contextPath="com.mycompany.foo" namespacePrefixRef="myMap"/> </marshal>
JaxbDataFormat jaxbDataFormat = new JaxbDataFormat(); jaxbDataFormat.setContextPath(Person.class.getPackage().getName()); jaxbDataFormat.setSchema("classpath:person.xsd,classpath:address.xsd"); jaxbDataFormat.setAccessExternalSchemaProtocols("file");
<marshal> <jaxb id="jaxb" schema="classpath:person.xsd,classpath:address.xsd" accessExternalSchemaProtocols="file"/> </marshal>
JaxbDataFormat jaxbDataFormat = new JaxbDataFormat(); jaxbDataFormat.setContextPath(Person.class.getPackage().getName()); jaxbDataFormat.setSchemaLocation("schema/person.xsd");
<marshal> <jaxb id="jaxb" schemaLocation="schema/person.xsd"/> </marshal>