How to trigger a handler class when consuming web-service in java

Question

Using Axis 1.4 I built client application that will consume external server services.

The server application response with soap message that include header tag along with body tag.

My problem with the header tag, I am trying to find away to get the header element.

What is done so far:

I found that I need to use a handler that extends BasicHandler using this class I can get the header tag. source: Dealing with SOAP Headers in Axis

But how to make this handler work when consuming web-service? I mean how to invoke this handler when ever I am receiving response from server to get its header.

Some blogs suggest I need to use .wsdd file. I am using Jdeveloper 11g with weblogic 10.3.6 environment where I am only aware of web.xml file for configuration.

Question: How to link those information(handler class, .wsdd file and web.xml) to gather and make the handler works to get the header tags?

Answer 1

The best start was to check Axis guide on: Apache-Axis Reference Guide where you will have an overview of the work flow.

To configure handlers to be trigger from the client side you need to do the following:

1- Create handler class basically something similar to the following:

package mypackge;

import javax.xml.soap.SOAPException;
import org.apache.axis.AxisFault;
import org.apache.axis.MessageContext;
import org.apache.axis.handlers.BasicHandler;
import org.apache.axis.message.SOAPHeader;
import org.apache.axis.message.SOAPHeaderElement;

public class SoapHeaderConsumerHandler
  extends BasicHandler
{
  public void invoke(MessageContext messageContext)
    throws AxisFault
  {
    // Your logic for request or response handling goes here. 
    // Basically you need to make use of the parameter
   // messageContext where you can access the soap header and body tags.
  }
}

2- Create the client-config.wsdd file. it will look like the following:

<deployment
    xmlns="http://xml.apache.org/axis/wsdd/"
    xmlns:java="http://xml.apache.org/axis/wsdd/providers/java">
    <globalConfiguration>
        <responseFlow>
            <handler name="log" type="java:mypackge.SoapHeaderConsumerHandler"/>
        </responseFlow>
    </globalConfiguration>
    <transport name="http" pivot="java:org.apache.axis.transport.http.HTTPSender"/>
</deployment>

You can see that I am using only handlers for the incoming response from the server side. So when ever the client application receive a response from the server the handler class SoapHeaderConsumerHandler will be triggered and the method invoke will be called by default.

Note: if you want to access the outgoing request before send it to the server you need to add extra tag for <requestFlow> to add request handler.

Check Deployment(WSDD) Reference from Axis guide:

3- Where to place the client-config.wsdd file ?

You should place the .wsdd file in the working directory. You can easily find out the working directory location using :

System.out.println("Working Directory = " + System.getProperty("user.dir"));

Source: Getting the Current Working Directory in Java

UPDATE:

I found out that it is not necessary to put the client-config.wsdd file in the working directory. You can specify the path of this file in your code as follow:

System.setProperty("axis.ClientConfigFile", "[Path goes here]\\client-config.wsdd");

You just need to place the .wsdd file there.

Extra Useful Links:

Where to place the client-config.wsdd file in Railo

V Axis handler This is an example for the server side handlers.

Dealing with SOAP Headers in Axis

Answer 2

To avoid file location problems you can programatically configure axis :

    ConsultationServiceLocator stub = new ConsultationServiceLocator();
    SimpleProvider clientConfig = new SimpleProvider();
    SoapHeaderConsumerHandler logHandler = new SoapHeaderConsumerHandler();
    SimpleChain reqHandler = new SimpleChain();
    SimpleChain respHandler = new SimpleChain();
    reqHandler.addHandler(logHandler);
    respHandler.addHandler(logHandler);
    Handler pivot = new HTTPSender();
    Handler transport = new SimpleTargetedChain(reqHandler, pivot, respHandler);
    clientConfig.deployTransport(HTTPTransport.DEFAULT_TRANSPORT_NAME, transport);