The usual way to construct a web service client is to include the Java interface for the service (the SEI) and any classes that are used for inputs and output in the client application. This is not always desirable or practical.
CXF supports several alternatives to allow an application to communicate with a service without the SEI and data classes. JAX-WS specified the Dispatch API, as well as the Provider interface for reading and writing XML. This page, however, describes the dynamic client facility of CXF. With dynamic clients, CXF generates SEI and bean classes at runtime, and allows you to invoke operations via APIs that take Objects, or by using reflection to call into full proxies.
Note that, in general, CXF only supports WSI-BP services. If you attempt to create a dynamic client for a WSDL that uses features outside of WSI-BP, CXF may throw an exception.
CXF provides two factory classes for dynamic classes. If your service is defined in terms of JAX-WS concepts, you should use the JaxWsDynamicClientFactory. If you do not want or need JAX-WS semantics, use the DynamicClientFactory. The remainder of this page uses the JaxWs version.
Let's pretend for a moment that you have a WSDL which defines a single operation "echo" which takes an input of a string and outputs a String. You could use the JaxWsDynamicClientFactory for it like this:
JaxWsDynamicClientFactory dcf = JaxWsDynamicClientFactory.newInstance(); Client client = dcf.createClient("echo.wsdl"); Object res = client.invoke("echo", "test echo"); System.out.println("Echo response: " + res);
Many WSDLs will have more complex types though. In this case the JaxWsDynamicClientFactory takes care of generating Java classes for these types. For example, we may have a People service which keeps track of people in an organization. In the sample below we create a Person object that was generated for us dynamically and send it to the server using the addPerson operation:
JaxWsDynamicClientFactory dcf = JaxWsDynamicClientFactory.newInstance(); Client client = dcf.createClient("people.wsdl", classLoader); Object person = Thread.currentThread().getContextClassLoader(). loadClass("com.acme.Person").newInstance(); Method m = person.getClass().getMethod("setName", String.class); m.invoke(person, "Joe Schmoe"); client.invoke("addPerson", person);
You may be asking yourself the following question: "Where did the class name 'com.acme.Person' come from?"
One way to get the class names is to run wsdl2java and examine the results. The dynamic client factory uses the same code generator as that tool. Another way is to walk the CXF service model. This has the advantage that it delivers Class<?> objects directly, so you don't need to obtain the correct class loader reference and run loadClass.
The wsdl_first_dynamic_client sample uses this approach. Read the file 'ComplexClient.java' to see the process, which uses some of the java.bean classes to simplify the code slightly.
The JaxWsDynamicClientFactory sets the Thread context ClassLoader to a new ClassLoader that contains the classes for the generated types. If you need the original ClassLoader, make sure you save it prior to calling createClient.