需要帮助解决 JAXB 解组问题

Question

I am having the typical 'unexpected element (uri:"", local:"stickynote")' JAXB error, although it only shows when I set the event handler on the unmarshaller object. When the event handler is not set code runs fine, but the specific data needed is not unmarshalled.

I have worked on the problem for a couple of days, including many Inte.net searches, and am not hitting on the right solution. I feel like I am missing something simple, but so far it is eluding me.

Notes:

1. I am using Java JDK 8 with Apache NetBeans 15.
2. The original code was generated with the xjc command from schemas we receive from multiple vendors. I cannot modify the schemas and have to figure out how to use them "as is".
3. I wrote the code below to duplicate the issue and simplify the posted code. Import statements have been removed for brevity. If they are needed please let me know.
4. Since inheritance is involved in one of the classes, I added the appropriate @XmlSeeAlso annotation. That did not help.
5. This is my first real foray into JAXB. It seems to be perfect for this project. I just have to figure out how to get it to work.

First, example XML:

<?xml version="1.0" encoding="UTF-8"?>
<documents>
    <document>
        <notes>
            <stickynote id="123">test note</stickynote>
        </notes>
    </document>
</documents>

Code to create the JAXB context and create the Unmarshaller object:

JAXBContext context = JAXBContext.newInstance( Documents.class );
Unmarshaller u = context.createUnmarshaller();
u.setEventHandler(new DefaultValidationEventHandler());

JAXBElement< Documents > root =
        u.unmarshal(
            new StreamSource( new File( FILENAME )),
            Documents.class );

The corresponding classes to handle each element:

Documents class

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "", propOrder = { "document" })
@XmlRootElement(name = "documents", namespace = "http://www.example.org/documents")
public class Documents {
    protected Document document;

    public Document getDocument() {
        return document;
    }

    public void setDocument(Document document) {
        this.document = document;
    }
}

Document class

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "", propOrder = { "notes" })
@XmlRootElement(name = "document", namespace = "http://www.example.org/documents")
public class Document {
    protected NotesType notes;

    public NotesType getNotes() {
        return notes;
    }

    public void setNotes(NotesType notes) {
        this.notes = notes;
    }
}

NotesType class

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "NotesType", propOrder = { "notes" })
public class NotesType {
    protected List<NoteType> notes;
    
    public List<NoteType> getNotes() {
        if ( isNull( notes )) {
            notes = new ArrayList<>();
        }

        return this.notes;
    }
}

NoteType class

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "NoteType", propOrder = { "note" })
@XmlSeeAlso({ StickyNote.class })
public class NoteType {
    @XmlAttribute(name = "id", required = true)
    protected String id;
    protected String note;

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getNote() {
        return note;
    }

    public void setNote(String note) {
        this.note = note;
    }
}

And finally, the StickyNote class, which extends the NoteType class:

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "", propOrder = { "subType" })
public class StickyNote extends NoteType {
    protected String subType = "sticky";

    public String getSubType() {
        return subType;
    }

    public void setSubType(String subType) {
        this.subType = subType;
    }
}

The exception is:

DefaultValidationEventHandler: [ERROR]: unexpected element (uri:"", local:"stickynote"). Expected elements are <{}notes> 
     Location: line 5 of file:/C:/Test/documents.xml
javax.xml.bind.UnmarshalException: unexpected element (uri:"", local:"stickynote"). Expected elements are <{}notes>
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext.handleEvent(UnmarshallingContext.java:726)

*and so on*

Thanks in advance for any and all suggestions and help!

john

Answer 1

My issue turned out to be how I was using xjc. I was building each schema we received individually, not realizing there was some overlap in the schemas due to the vendors using other vendors schemas. This caused issues when one vendor's schema was built early in the process and then another vendor's schema was built after it that used the earlier vendor's schema.

Building all the schemas as a group, instead of individually, allowed xjc to "see" everything it needed to see and the corresponding code worked as expected.