Question

I am expecting a XML generated by JAXB which has the following pattern:

<payload>
   <parameters>
      <paramName>clientAssocIds</paramName>
      <paramVal>0207</paramVal>
      <paramName>quoteType</paramName>
      <paramVal>NTB</paramVal>
      <paramName>quoteDateLimitDays</paramName>
      <paramVal>365</paramVal>
      <paramName>externalIndicator</paramName> 
      <paramVal>1</paramVal>
   </parameters>
</payload>

The <paramName> and <paramVal> are name and value pairs, which means <paramVal> has to follow <paramName>.

I wrote a XML Schema and use JAXB to generate the java class based on this schema, then I set all the values and marshalled the class, it didn’t generate the xml pattern I expected above.

Here is my schema:

<xsd:complexType name="sgrpCommonMessage">
  <xsd:sequence>
    <xsd:element name="payload" type="payload" />
  </xsd:sequence>
</xsd:complexType>



<xsd:complexType name="payload">
  <xsd:sequence>
    <xsd:choice minOccurs="0" maxOccurs="1">
        <xsd:element name="parameters" type="parameter" />
    </xsd:choice>
  </xsd:sequence>
</xsd:complexType>

<xsd:complexType name="parameter">
  <xsd:sequence>
    <xsd:element minOccurs="0" name="paramName" type="xsd:string" />
    <xsd:element minOccurs="0" name="paramVal" type="xsd:string" />
  </xsd:sequence>
</xsd:complexType>

And the generated xml has a few <parameters>, which is not what I expect. I want to wrap all the <paramName> and <paramVal> pairs in one <parameters>:

<payload>
  <parameters>
    <paramName>quoteDateLimitDays</paramName>
    <paramVal>NTB</paramVal>
  </parameters>
  <parameters>
    <paramName>clientAssocIds</paramName>
    <paramVal>0207</paramVal>
  </parameters>
  <parameters>
    <paramName>quoteType</paramName>
    <paramVal>NTB</paramVal>
  </parameters>
  <parameters>
    <paramName>externalIndicator</paramName>
    <paramVal>NTB</paramVal>
  </parameters>
</payload>

I am wondering if JAXB is capable of realizing such XML structure, if not, what API should I use, if yes, how?

Answer 1

You could have an XML schema like the following:

<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">

    <xsd:element name="parameters" type="parameters" />

    <xsd:complexType name="parameters">
        <xsd:sequence minOccurs="0" maxOccurs="unbounded">
            <xsd:element name="paramName" type="xsd:string" />
            <xsd:element name="paramValue" type="xsd:string" />
        </xsd:sequence>
    </xsd:complexType>

</xsd:schema>

Then with the generated model you could do:

import javax.xml.bind.*;

public class Demo {

    public static void main(String[] args) throws Exception {
        JAXBContext jc = JAXBContext.newInstance("forum14571803");

        ObjectFactory objectFactory = new ObjectFactory();

        Parameters parameters = objectFactory.createParameters();
        parameters.getParamNameAndParamValue().add(objectFactory.createParametersParamName("A"));
        parameters.getParamNameAndParamValue().add(objectFactory.createParametersParamValue("a"));
        parameters.getParamNameAndParamValue().add(objectFactory.createParametersParamName("B"));
        parameters.getParamNameAndParamValue().add(objectFactory.createParametersParamValue("b"));

        JAXBElement<Parameters> root = objectFactory.createParameters(parameters);

        Marshaller marshaller = jc.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        marshaller.marshal(root, System.out);
    }

}

Which would give you the following output:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<parameters>
    <paramName>A</paramName>
    <paramValue>a</paramValue>
    <paramName>B</paramName>
    <paramValue>b</paramValue>
</parameters>