[CONF] Apache CXF 2.0 Documentation: MTOM Attachments (page created)

Tue, 17 Apr 2007 15:58:45 -0700

Page Created : CXF20DOC : MTOM Attachments

MTOM Attachments has been created by Dan Diephouse (Apr 17, 2007).

Content:

MTOM is a standard which allows your services to transfer binary data efficiently and conveniently. Many frameworks have support for MTOM - Axis2, JAX-WS RI, JBoss WS, XFire, and more.

If the binary is part of the XML document, it needs to be base64 encoded - taking CPU time and increasing the payload size. When MTOM is enabled on a service, it takes binary data which might normally be part of the XML document, and creates an attachment for it.

Enabling MTOM is a rather simple process. First, you must annotate your schema type or POJO to let JAXB know that a particular field could be a candidate for MTOM optimization. Second, you just tell CXF that you wish to enable MTOM.

1a) Modifying your schema for MTOM

Lets say we have a Picture schema type like this:

<schema targetNamespace="http://pictures.com"
  xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <element name="Picture">
    <complexType>
      <sequence>
        <element name="Title" type="xsd:string"/>
        <element name="ImageData" type="xsd:base64Binary"/>
      </sequence>
    </complexType>
  </element>
</schema>

In this case the ImageData element is something we would like to have transferred as an attachment. To do this we just need to add an xmime:expectedContentTypes annotation:

<schema targetNamespace="http://pictures.com" 
  xmlns:xsd="http://www.w3.org/2001/XMLSchema"
  xmlns:xmime="http://www.w3.org/2005/05/xmlmime">
  <element name="Picture">
    <complexType>
      <sequence>
        <element name="Title" type="xsd:string"/>
        <element name="ImageData" type="xsd:base64Binary"
           xmime:expectedContentTypes="application/octet-stream"/>
      </sequence>
    </complexType>
  </element>
</schema>

This tells JAXB (which WSDL2Java uses to generate POJOs for your service) that this field could be of any content type. Instead of creating a byte[] array for the base64Binary element, it will not create a DataHandler instead which can be used to stream the data.



1b) Annotation your JAXB beans to enable MTOM


If you're doing code first, you need to add an annotation to your POJO to tell JAXB that the field is a candidate for MTOM optimization. Lets say we have a Picture class with has Title and ImageData fields, then it might look like this:




@XmlType
public class Picture {
  private String title;

  @XmlMimeType("application/octet-stream")
  private DataHandler imageData;

  public String getTitle() { return title; }
  public void setTitle(String title) { this.title = title; }

  public DataHandler getImageData() { return imageData; }
  public void setImageData(DataHandler imageData) { this.imageData = imageData; }
}





Enable MTOM on your service


If you've used JAX-WS to publish your endpoint you can enable MTOM like so:




import javax.xml.ws.Endpoint;
import javax.xml.ws.soap.SOAPBinding;

Endpoint ep = Endpoint.publish("http://localhost/myService", new MyService());
SOAPBinding binding = (SOAPBinding) ep.getBinding();
binding.setMTOMEnabled(true);





Or, if you used XML to publish your endpoint:




<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:jaxws="http://cxf.apache.org/jaxws"
	xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
http://cxf.apache.org/jaxws http://cxf.apache.org/schema/jaxws.xsd">

  <jaxws:endpoint 
    id="helloWorld" 
    implementor="demo.spring.HelloWorldImpl" 
    address="http://localhost/HelloWorld">
    <jaxws:properties>
      <entry key="mtom-enabled" value="true"/>
    </jaxws:properties>
  </jaxws:endpoint>

</beans>
{code{


h3. Using DataHandlers
Once you've got the above done, its time to start writing your logic. DataHandlers are easy to use and create. To consume a DataHandler:
{code:java}
Picture picture = ...;
DataHandler handler = picture.getImageData();
InputStream is = handler.getInputStream();





There are many ways to create DataHandlers. You can use a FileDataSource, ByteArrayDataSource, or write your own DataSource:




DataSource source = new ByteArrayDataSource(new byte[] {...}, "content/type");
DataSource source = new FileDataSource(new File("my/file"));

Picture picture = new Picture();
picture.setImageData(new DataHandler(source));

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