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<h4><A NAME="wsmigj2ee"></A>Migrate Apache SOAP Web services to Web services for J2EE</h4>
<p>If you have used the Apache SOAP support to create Web
services client applications in WebSphere Application Server - Express Version 5.0 and want use Web
services for J2EE, also known as JSR 109, you need
to migrate your Version 5.0 client applications.</p>
<p>To migrate these client applications to the JSR 109 Web services
standards:</p>
<ol>
<li>Plan your migration strategy.
<p>There are two ways you can port an Apache SOAP client to Java API for
XML-based RPC (JAX-RPC) Web services client:</p>
<ul><li>If you have, or can create, a Web Services Description Language
(WSDL) document for the service, consider using the <strong>WSDL2Java</strong> command
tool to generate bindings for the Web service. It is more work to adapt an
Apache SOAP client to use the generated JAX-RPC bindings, but the resulting
client code is more robust and easier to maintain. To follow this path, see <a
href="../webserv/wsdevclient.htm">Develop a Web services client</a> in the <em>Web services</em> topic.</li>
<li>If you do not have a WSDL document for the service, do not expect
the service to change, and you want to port the Apache SOAP client with a
minimal work, you can convert the code to use the JAX-RPC dynamic invocation
interface (DII), which is similar to the Apache SOAP APIs. The DII APIs do
not use WSDL or generated bindings.</li></ul>
<p>You should be aware that since JAX-RPC does not specify a framework
for user-written serializers, the JAX-RPC does not support the use of custom
serializers. If your application cannot conform to the default mapping between
Java, WSDL, and XML supported by WebSphere Application Server - Express, you should
not attempt to migrate the application. </p>
<p>The remainder of this topic assumes that you have decided to use the
JAX-RPC DII APIs. </p>
</li>
<li>Convert the client application from Apache SOAP to JAX-RPC DII
<p>The Apache SOAP API and JAX-RPC DII API structures are similar. You
can instantiate and configure a call object, set up the parameters, invoke
the operation, and process the result in both. </p>
<p>You can create a generic instance of a Service object with</p>
<pre>javax.xml.rpc.Service service =
ServiceFactory.newInstance().createService(new QName(&quot;&quot;));</pre> in JAX-RPC.
<ol type="a">
<li>Create the call object.
<p>An instance of the call object is created by </p>
<pre>org.apache.soap.rpc.Call call = new org.apache.soap.rpc.Call ()</pre> in
Apache SOAP.
<p>An instance of the call object is created by </p>
<pre>java.xml.rpc.Call call = service.createCall();</pre> in
JAX-RPC.
</li>
<li>Set the endpoint URI.
<p>The target URI for the operation is passed as a parameter to</p>
<pre>call.invoke: call.invoke(&quot;http://...&quot;, &quot;&quot;);</pre> in
Apache SOAP.
<p>The setTargetEndpointAddress method is used as a parameter to</p>
<pre>parametcall.setTargetEndpointAddress(&quot;http://...&quot;);</pre>in JAX-RPC.
<p>Apache SOAP has a setTargetObjectURI method on the call object that contains routing
information for the request. JAX-RPC has no equivalent method. The information
in the targetObjectURI is included in the targetEndpoint URI for JAX-RPC. </p>
</li>
<li>Set the operation name.
<p>The operation name is configured on the call object by</p>
<pre>call.setMethodName(&quot;opName&quot;);</pre> in
Apache SOAP.
<p>The setOperationName method, which accepts a <tt>QName</tt> instead
of a <tt>String</tt> parameter, is used in JAX-RPC as follows:</p>
<pre>call.setOperationName(new javax.xml.namespace.Qname(&quot;namespace&quot;,
&quot;opName&quot;));</pre>
</li>
<li>Set the encoding style.
<p>The encoding style is configured on the call object by</p>
<pre>call.setEncodingStyleURI(org.apache.soap.Constants.NS_URI_SOAP_ENC);</pre> in
Apache SOAP.
<p>The encoding style is set by a property of the call object</p>
<pre>call.setProperty(javax.xml.rpc.Call.ENCODINGSTYLE_URI_PROPERTY,
&quot;http://schemas.xmlsoap.org/soap/encoding/&quot;);</pre>in
JAX-RPC.
</li>
<li>Declare the parameters and set the parameter values.
<p>Apache SOAP parameter types and values are described by parameter instances,
which are collected into a Vector and set on the call object before the call,
for example: </p>
<pre>Vector params = new Vector ();
params.addElement (new org.apache.soap.rpc.Parameter(name,
type, value, encodingURI));
// repeat for additional parameters... call.setParams (params);</pre>
<p>For
JAX-RPC, the call object is configured with parameter names and types without
providing their values, for example: </p>
<pre>call.addParameter(<em>name</em>, <em>xmlType</em>, <em>mode</em>);
// repeat for additional parameters call.setReturnType(<em>type</em>);</pre> Where<ul>
<li><em>name</em> (type <tt>java.lang.String</tt>) is the name of the parameter</li>
<li><em>xmlType</em> (type <tt>javax.xml.namespace.QName</tt>) is the XML type
of the parameter</li>
<li><em>mode</em> (type <tt>javax.xml.rpc.ParameterMod</tt>e) the mode of the
parameter, for example, IN, OUT, or INOUT</li>
</ul>
</li>
<li>Make the call.
<p>The operation is invoked on the call object by </p>
<pre>org.apache.soap.Response resp = call.invoke(endpointURI, &quot;&quot;);</pre> in
Apache SOAP.
<p>The parameter values are collected into an array and passed
to <tt>call.invoke</tt> as follows: </p>
<pre>Object resp = call.invoke(new Object[] {parm1, parm2,...});</pre> in
JAX-RPC.
</li>
<li>Check for faults.
<p>You can check for a SOAP fault on the invocation by checking the Response:</p>
<pre>if resp.generatedFault then {
org.apache.soap.Fault f = resp.getFault;
f.getFaultCode();
f.getFaultString(); }</pre>in Apache SOAP.
<p>A <tt>java.rmi.RemoteException</tt> is
thrown in JAX-RPC if a SOAP fault occurs on the invocation.</p>
<pre>try
... call.invoke(...)
catch (java.rmi.RemoteException) ...</pre>
</li>
<li>Retrieve the result.
<p>In Apache SOAP, if the invocation was successful and returns a result,
it can be retrieved from the Response object: </p>
<pre>Parameter result = resp.getReturnValue(); return result.getValue();</pre>
<p>In
JAX-RPC, the result of invoke is the returned object when no exception is
thrown: </p>
<pre>Object result = call.invoke(...);
...
return result;</pre>
</li>
</ol>
</li>
</ol>
<p><strong>Note: </strong>Examples might be wrapped for display purposes.</p>
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