jaxb with existing classes and schema

Question

Is it possible to map existing xml schema to existing java classes?

I have several xml schemas and I need to map them all to one java class. Xml files differs a bit in way of storing data. E.g.

public class DataStorage {
   public String data1;
   public String data2;
   public String data3;
}

and set of different xml files

<?xml ...?>
<dataCase1>
<data1>...</data1>
<data2>...</data2>
<data3>...</data3>
</dataCase1>

<?xml ...?>
<dataCase2>
<data data1="..." data2="..." data3="..." />
</dataCase2>

<?xml ...?>
<dataCase3>
<data>
<innerData>
<data1>...</data1>
</innerData>
<otherData data2="...">
<data3>...</data3>
</otherData>
</data>
</dataCase3>

There could be many other variants of xml files.

Is it possible to bind all that files to java class using jaxb?

Yes, you can. Build packages for each xml-schema and bind them to your class. — umbr, Sep 05 '11 at 19:55

score 2 · Accepted Answer · answered Sep 05 '11 at 20:49

You could use the EclipseLink MOXy implementation of JAXB to achieve this. As far as I understand, you will still have to create different classes for different types of schema but you can reuse your domain objects.

To continue with your example:

DataStorage class with 3 domain objects(data1, data2, data3), simplistically represented as Strings, can be really any JAXB mapped domain object.

Schema type 1

@XmlRootElement(name = "dataCase")
@XmlAccessorType(XmlAccessType.FIELD)
public class DataStorage {
    private String data1;
    private String data2;
    private String data3;

    /**
     * No-arg ctor needed by jaxb.
     */
    private DataStorage() {}

    public DataStorage(String data1, String data2, String data3) {
        this.data1 = data1;
        this.data2 = data2;
        this.data3 = data3;
    }

}

Schema type 2. Note the use of the @XmlPath annotation.

 @XmlRootElement(name = "dataCase")
 @XmlAccessorType(XmlAccessType.FIELD)
 public class DataStorage {
     @XmlPath("data/@data1")
     private String data1;
     @XmlPath("data/@data2")
     private String data2;
     @XmlPath("data/@data3")
     private String data3;
 ....

Schema type 3. Again leveraging @XmlPath.

@XmlRootElement(name = "dataCase")
@XmlAccessorType(XmlAccessType.FIELD)
public class DataStorage {
    @XmlPath("data/innerData/data1/text()")
    private String data1;
    @XmlPath("data/otherData/@data2")
    private String data2;
    @XmlPath("data/otherData/data3/text()")
    private String data3;
....

Marshalling

JAXBContext jc = JAXBContext.newInstance(DataStorage.class);
Marshaller marshaller = jc.createMarshaller();
DataStorage dataStorage = new DataStorage("data 1", "data 2", "data 3");
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
marshaller.marshal(dataStorage, System.out);

See this post from the MOXy team lead's blog for me information.

+1 - You can also use MOXy's XML metadata file to apply multiple mappings to your domain model. For an example see: http://stackoverflow.com/questions/6838882/jaxb-annotations-extract-xml-value-from-xml-element — bdoughan, Sep 06 '11 at 14:09
@Blaise That looks great. This will come in handy some time :) — Sahil Muthoo, Sep 06 '11 at 16:25
Here is a more detailed example I put together demonstrating multiple mappings on a single object model: http://blog.bdoughan.com/2011/09/mapping-objects-to-multiple-xml-schemas.html — bdoughan, Sep 08 '11 at 19:25

score 1 · Answer 2 · answered Feb 16 '12 at 06:34

1

You could use XSLT to translate your different XML formats into a single unified one.

answered Feb 16 '12 at 06:34

Jules

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jaxb with existing classes and schema

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