无法使用生成的JAXB类解析XML文件

Question

I am trying to generate JAXB bindings from this xsd file according to this tutorial . Firstly I noticed that there are some dependencies, but I managed to get them off the same address. After I downloaded them I ran

xjc net_file.xsd

This did generate some java code, however unlike in the tutorial the files look like "...Type.java". I find this inconvenient, but I could live with it. After that I tried to parse the given example file:

File file = new File("quickstart.net.xml");
JAXBContext jaxbContext = JAXBContext.newInstance(NetType.class);
Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
NetType net = (NetType) jaxbUnmarshaller.unmarshal(file);

However, I get the following exception:

Exception in thread "main" javax.xml.bind.UnmarshalException: unexpected element (uri:"", local:"net"). Expected elements are (none)

Does anyone know what I am doing wrong?

Answer 1

I think your XML file is defined by two XSDs. See here:

xsi:noNamespaceSchemaLocation="http://sumo.dlr.de/xsd/netconvertConfiguration.xsd" and xsi:noNamespaceSchemaLocation="http://sumo.dlr.de/xsd/net_file.xsd

You will either miss net or configuration element.

I don't know how JAXB can support partial XSDs. Are you sure you follow the tutorial correctly? You should be able to merge these two xsd files into one (?).

Answer 2

Well, I found the problem. It seems that you actually need to use the generated ObjectFactory . I modified the code like this:

    File file = new File("quickstart.net.xml");
    JAXBContext jaxbContext = JAXBContext.newInstance(ObjectFactory.class);
    Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
    JAXBElement<NetType> netElement = (JAXBElement<NetType>) jaxbUnmarshaller.unmarshal(file);

Now everything works. I guess the reason is that the ObjectFactory has an annotated builder method:

/**
 * Create an instance of {@link JAXBElement }{@code <}{@link NetType }{@code >}}
 * 
 */
@XmlElementDecl(namespace = "", name = "net")
public JAXBElement<NetType> createNet(NetType value) {
    return new JAXBElement<NetType>(_Net_QNAME, NetType.class, null, value);
}

Imho this is really over-engineered but whatever :)