Extracting SOAP attachments with Axis

It was a little hard to find this information today, so I think it would be interesting to share it here. First, what I wanted was to get the attachment for a SOAP response. The response was empty, but the attachment had a png I needed to display in my Wicket application.

It turns out that it is very simple to extract SOAP attachments. All you have to do is to write a handler that will be called during the web service call. Any number of handlers can be set in the BindingProvider. For example, this is my code to set the handlers:

MyServicePort port = mws.getMyServicePort();
BindingProvider bp = (BindingProvider) port;
bp.getRequestContext().put(
           BindingProvider.ENDPOINT_ADDRESS_PROPERTY,
           DEFAULT_WS_URL);
Binding binding = bp.getBinding();
     
// Add the logging handler
List handlerList = binding.getHandlerChain();
if (handlerList == null) {
    handlerList = new ArrayList();
    binding.setHandlerChain(handlerList);
}
     
handlerList.add(handler);

With this code, we only need to write our handler which will handle the message and can do whatever it wants with it - including accessing attachments.

public class SOAPAttachmentHandler
    implements SOAPHandler<SOAPMessageContext> {
   private Collection<Attachment> attachments;
 
   @Override
   public boolean handleFault(SOAPMessageContext context) {
       context.getMessage();
       return true;
   }

   @Override
   public boolean handleMessage(SOAPMessageContext context) {
       attachments = ((SOAPMessageContextImpl)context).
                           getWrappedMessage().getAttachments();
       return true;
   }

   @Override
   public Set<QName> getHeaders() {
       return null;
   }

   @Override
   public void close(MessageContext context) {
       // blank
   }

   public Collection<Attachment> getAttachments() {
       return attachments;
   }

The class above extracts the attachments and store then in a class variable. After invoking the web service, I can access the attachments.