Axis2 - Adding custom SOAP Headers to a request using ServiceClient

The Axis2 ServiceClient API provides three main ways of adding SOAP Headers to a request. Lets take a look at how this could be done,

• Add a simple header which contains a String to the request

serviceClient.addStringHeader(new QName("http://wso2.org", "ThirdHeader"), "This is a sample Header");

This is the simplest method of adding a header. But this method restricts you to simple String headers.

• Creating a header as a OMElement and adding it to the request

OMElement firstHeader = AXIOMUtil.stringToOM(
        "This is a sample Header");
serviceClient.addHeader(firstHeader);

Users are expected to create the complete header themselves using Axiom's OMElement APIs.

• Creating a header as a SOAPHeaderBlock and adding it to the request

OMNamespace omNamespace =
        OMAbstractFactory.getOMFactory().createOMNamespace("http://wso2.com", "ws");
SOAPHeaderBlock secondHeader = OMAbstractFactory.getSOAP12Factory().createSOAPHeaderBlock("SecondHeader", omNamespace);
secondHeader.addChild(AXIOMUtil.stringToOM("This is a sample Header"));
//secondHeader.setMustUnderstand(true);
serviceClient.addHeader(secondHeader);

Users are expected to create the header using Axiom's SOAP APIs. Users could use the API to set various options on the header such as the MustUnderstand Attribute.

Axiom - How to create a OMElement from a String

If someone is using Axis2's ServiceClient to send a request to a service they will have to deal with OMElements. That is because ServiceClient accepts the payload as a OMElement. Using Axiom API's to create this OMElement could be time consuming and may take several lines of code. Alternatively users could create this OMElement from a String as follows,

OMElement payload = AXIOMUtil.stringToOM("Hi! This is a sample Request.");

This utility method that comes with Axiom takes in a String as the argument and returns an OMElement.