Simple Java Xml to POJO mapping/binding?

问题:

I'm trying to figure out the simplest way to map an xml file to to a plain old java object.

Note: That in my example the xml doesn't quite match up with my intended POJO.

///////// THE XML
<?xml version="1.0" encoding="UTF-8"?>
<Animal>
  <standardName>
    <Name>Cat</Name>
  </standardName>
  <standardVersion>
    <VersionIdentifier>V02.00</VersionIdentifier>
  </standardVersion>
</Animal>


////// THE INTENDED POJO
class Animal
{
 private String name;
 private String versionIdentifier;
}

Regular JAXB (with annotations) won't work as the JAXM Element name annotations don't allow me to specifiy nested elements. (i.e. standardName/Name).

I've looked at Jibx but it seems overly complicated, and no full examples are provided for what I want to do.

Castro seems like it would be able to do what I want (using mapping files), but I wonder if there are any other possible solutions. (Possibly that would allow me to skip mapping files, and just allow me to specify everything in annotations).

Thanks

回答1:

This article may help you... it only requires you to know xpath http://onjava.com/onjava/2007/09/07/schema-less-java-xml-data-binding-with-vtd-xml.html

回答2:

EclipseLink JAXB (MOXy) allows you to do the path based mapping that you are looking for:

@XmlRootElement 
class Animal 
{ 
 @XmlPath("standardName/Name/text()")
 private String name; 

 @XmlPath("standardVersion/VersionIdentifier/text()");
 private String versionIdentifier; 
} 

For more information see:

• http://bdoughan.blogspot.com/2010/09/xpath-based-mapping-geocode-example.html
• http://bdoughan.blogspot.com/2010/07/xpath-based-mapping.html
• http://wiki.eclipse.org/EclipseLink/Examples/MOXy/GettingStarted/MOXyExtensions

EclipseLink also allows the metadata to be specified using an external configuration file:

• http://wiki.eclipse.org/EclipseLink/Examples/MOXy/GettingStarted/ExternalizedMetadata

回答3:

Jakarta Commons Digester should do what you want.

Alternatively, I would recommend writing a transformation class that uses XPath to retrieve elements from the XML.

回答4:

I consider JiBX the best of the bunch (JAXB, Castor, XMLBeans, etc.), particularly because I favor mapping files over annotations. Admittedly it has a decent learning curve, but the website has a lot of good examples. You must have missed the tutorial.

If you are only going one way (XML --> POJO) you could use Digester.

Side comment: I prefer mapping files over annotations because annotations:

• clutter the code (especially when using annotations from several products)
• mix concerns (XML, database, etc. in domain layer)
• can only bind to a single XML (or database, or web service, etc.) representation