Spring Integration Marshalling with JAXB

The project I was working on used SOAP based Web Services. The .wsdl and .xsd files that described the services we needed to integrate with were provided by the vendor. Often times I needed to access information in the SOAP responses, or I needed to easily build a SOAP request object. While you can work directly with the XML, it is much easier to use marshalling/unmarshalling techniques. Being a proof of concept I chose JAXB to do the marshalling/unmarshalling. There may be better choices depending on your needs and most likely spring integration supports it.

While it is possible to create by hand JAXB Java classes, it seems to make more sense to use the xjc tool and generate the classes automatically. I will not go into great detail on using this tool as there are other resources that do that. xjc was on my class path, so I was able to navigate to the directory containing the .xsd and .wsdl files. I created a directory there called temp and ran the following command on each of the files that I needed classes generated for, which would create all the classes I needed in the appropriate directory structure under temp.

xjc -d temp myVendorFile.xsd

Now that the files had been generated it was a matter of configuring spring to use them. There are several ways to go about this. You can create a generic marshaller that handles all classes, or you can create more targeted marshallers. If you are creating a generic one you might just set the id to marshaller, if you want more targeted the id name will reflect something more specific.

    <bean id="marshaller" class="org.springframework.oxm.jaxb.Jaxb2Marshaller">
        <property name="classesToBeBound">
            <list>
                <value>com.vendor.JAXBClass1</value>>
                <value>com.vendor.JAXBClass2</value>
                <value>com.vendor.JAXBClass3</value>
            </list>
        </property>
    </bean>

    <bean id="myServiceClient" class="com.company.project.ws.MyServiceClient">
        <property name="marshaller" ref="marshaller"/>
        <property name="unmarshaller" ref="marshaller"/>
    </bean>

the class MyServiceClient extends the spring WebServiceGatewaySupport class. This is an easy way to send requests and receive responses. Inside your class you can create the request object that you want sent using the JAXB ObjectFactory methods.

MyRequest myRequest = new ObjectFactory().createMyRequest(); 

Then you can set individual elements on that object, whatever they are. The request is sent by using a method from the Spring class. The SoapAction is not set automatically, so it needs to be set manually.

MyResponse myResponse = getWebServiceTemplate().marshallSendAndReceive(serviceUri, myRequest, new WebServiceMessageCallback() { public void doWithMessage(WebServiceMessage message) {
((SoapMessage)message).setSoapAction("MySoapAction");}});

That's really all there is to it. As you can see the above method automatically marshalls the request to XML and unmarshalls the response to the JAXB Java object. Also it is good to surround that method call with a try catch so that if there is a problem on the other end, your software can react appropriately.