Question

When trying to parse the method return type, method name, and parameters from the following WSDL (xml document), I get null each time I try to retrieve something from the DOM document:

<?xml version="1.0" encoding="UTF-8"?>
<wsdl:definitions targetNamespace="http://math" xmlns:apachesoap="http://xml.apache.org/xml-soap" xmlns:impl="http://math" xmlns:intf="http://math" xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/" xmlns:wsdlsoap="http://schemas.xmlsoap.org/wsdl/soap/" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<!--WSDL created by Apache Axis version: 1.4
Built on Apr 22, 2006 (06:55:48 PDT)-->
 <wsdl:types>
  <schema elementFormDefault="qualified" targetNamespace="http://math" xmlns="http://www.w3.org/2001/XMLSchema">
   <element name="addTwoInts">
    <complexType>
     <sequence>
      <element name="int1" type="xsd:int"/>
      <element name="int2" type="xsd:int"/>
     </sequence>
    </complexType>
   </element>
   <element name="addTwoIntsResponse">
    <complexType>
     <sequence>
      <element name="addTwoIntsReturn" type="xsd:int"/>
     </sequence>
    </complexType>
   </element>
   <element name="multiplyTwoFloats">
    <complexType>
     <sequence>
      <element name="float1" type="xsd:float"/>
      <element name="float2" type="xsd:float"/>
     </sequence>
    </complexType>
   </element>
   <element name="multiplyTwoFloatsResponse">
    <complexType>
     <sequence>
      <element name="multiplyTwoFloatsReturn" type="xsd:float"/>
     </sequence>
    </complexType>
   </element>
  </schema>
 </wsdl:types>

   <wsdl:message name="addTwoIntsResponse">

      <wsdl:part element="impl:addTwoIntsResponse" name="parameters">

      </wsdl:part>

   </wsdl:message>

   <wsdl:message name="addTwoIntsRequest">

      <wsdl:part element="impl:addTwoInts" name="parameters">

      </wsdl:part>

   </wsdl:message>

   <wsdl:message name="multiplyTwoFloatsRequest">

      <wsdl:part element="impl:multiplyTwoFloats" name="parameters">

      </wsdl:part>

   </wsdl:message>

   <wsdl:message name="multiplyTwoFloatsResponse">

      <wsdl:part element="impl:multiplyTwoFloatsResponse" name="parameters">

      </wsdl:part>

   </wsdl:message>

   <wsdl:portType name="MathServices">

      <wsdl:operation name="addTwoInts">

         <wsdl:input message="impl:addTwoIntsRequest" name="addTwoIntsRequest">

       </wsdl:input>

         <wsdl:output message="impl:addTwoIntsResponse" name="addTwoIntsResponse">

       </wsdl:output>

      </wsdl:operation>

      <wsdl:operation name="multiplyTwoFloats">

         <wsdl:input message="impl:multiplyTwoFloatsRequest" name="multiplyTwoFloatsRequest">

       </wsdl:input>

         <wsdl:output message="impl:multiplyTwoFloatsResponse" name="multiplyTwoFloatsResponse">

       </wsdl:output>

      </wsdl:operation>

   </wsdl:portType>

   <wsdl:binding name="MathServicesSoapBinding" type="impl:MathServices">

      <wsdlsoap:binding style="document" transport="http://schemas.xmlsoap.org/soap/http"/>

      <wsdl:operation name="addTwoInts">

         <wsdlsoap:operation soapAction=""/>

         <wsdl:input name="addTwoIntsRequest">

            <wsdlsoap:body use="literal"/>

         </wsdl:input>

         <wsdl:output name="addTwoIntsResponse">

            <wsdlsoap:body use="literal"/>

         </wsdl:output>

      </wsdl:operation>

      <wsdl:operation name="multiplyTwoFloats">

         <wsdlsoap:operation soapAction=""/>

         <wsdl:input name="multiplyTwoFloatsRequest">

            <wsdlsoap:body use="literal"/>

         </wsdl:input>

         <wsdl:output name="multiplyTwoFloatsResponse">

            <wsdlsoap:body use="literal"/>

         </wsdl:output>

      </wsdl:operation>

   </wsdl:binding>

   <wsdl:service name="MathServicesService">

      <wsdl:port binding="impl:MathServicesSoapBinding" name="MathServices">

         <wsdlsoap:address location="http://localhost:8080/WSDLServer"/>

      </wsdl:port>

   </wsdl:service>

</wsdl:definitions>

Here’s what I’ve tried to do programmatically:

DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

        try {
            DocumentBuilder db = dbf.newDocumentBuilder();

            //parse using builder to get DOM representation of the XML file
            Document doc = db.parse("MathServices.xml");

            Node firstChild = doc.getFirstChild();
            System.out.println(firstChild.getNodeValue());


        }catch(ParserConfigurationException pce) {
            pce.printStackTrace();
        }catch(SAXException se) {
            se.printStackTrace();
        }catch(IOException ioe) {
            ioe.printStackTrace();
        }

As I mentioned, firstNode.getNodeValue() is returning null. I also get null values when trying to get other things such as the root node, etc. What am I doing wrong here?

Answer 1

The node firstChild seems to be a valid object (unequal to zero), otherwise you would get a null pointer exception when calling firstChild.getNodeValue().

If you want to access the node name, use “doc.getNodeName()” rather than “doc.getNodeValue()”. The latter one gives you the content of the tag (without any content of child tags) that is listed between opening and closing tag, but not the tagname or any attributes.
Moreover as the root tag “wsdl:definition” (in the example file) defines child tags, there cannot be any text content for it at the same time.