Import/Export of XML data with a database

patrick_ibg · **Joined:** Sat Sep 17, 2005 10:41 am **Posts:** 49

I'm using Hibernate 3.1 with Annotations.

Anybody know of a quick, elegant solution for exporting database data to XML? I would prefer to use my existing POJO -> HBM mappings to transparently describe the XML entities. The inverse would be useful as well (importing XML data into a database).

I've heard of XMLDatabinder which AFAIK is for Hibernate 2 only. Is there anything similar in Hibernate 3.1?

Thanks in advance...

kochcp · **Posted:** Thu Sep 22, 2005 2:14 pm

I've never looked in hibernate for this kind of functionality, but the dbunit project on sourceforge exports and imports data to and from (in xml documents) the database.

It does not use your hbm files, but it has worked ok for me.

christian · **Posted:** Thu Sep 22, 2005 2:15 pm

You can switch Hibernate to EntityMode.DOM4J and export the resulting documents to a file.

patrick_ibg · **Joined:** Sat Sep 17, 2005 10:41 am **Posts:** 49

Trying this, and I'm getting a "No tuplizer found for entity-mode [DOM4J]" error.

I suspect I need to add XML-entity annotations to my annotated POJO???? I've tried searching but I can't find where the XML-entity annotation extensions are (if they in fact exist).

Here's the annotated POJO:

Code:

@Entity (access = AccessType.FIELD)
public class State
  implements java.io.Serializable
{
@Id (generate = GeneratorType.NONE)
@Column (length = 2)
protected String key ;

@Column (length = 64)
protected String name ;

public State (String key, String name)
{
  this.key = key ;
  this.name = name ;
}   
    
public String getKey () { return this.key ; }
public void setKey (String p) { this.key = p ; }
...
      
}   

Here's the data access code:

Code:

public static void main (String [] args)
{               
  Transaction tx      = null ;
  Session     session = null ;
                
  try {     
    Document document = DocumentHelper.createDocument();
    Element root = document.addElement ("root");
            
    Configuration  configuration = new AnnotationConfiguration() ;
    configuration.configure() ;
    SessionFactory factory = configuration.buildSessionFactory();
            
    session = factory.openSession();
    Session dom4jSession = session.getSession (EntityMode.DOM4J) ;
    tx = dom4jSession.beginTransaction () ;
                
    Element element = (Element) dom4jSession.get (State.class, "NY") ;
    root.add (element) ;
    
    document.write (new FileWriter ("test.xml")) ;
  }
  catch (Exception e) {
    e.printStackTrace () ;
  }
  finally {
    if (tx != null)
      tx.commit () ;

    if (session != null)
      session.close () ;
  }
}

christian · **Posted:** Thu Sep 22, 2005 4:01 pm

It's in the documentation...

patrick_ibg · **Joined:** Sat Sep 17, 2005 10:41 am **Posts:** 49

Hrm... maybe I'm looking in the wrong places?

So far, I've only seen examples of

Code:

session.getSession(EntityMode.DOM4J)

in the context of Hibernate 3.0.x using hbm.xml files. I haven't seen any documentation on XML import/export using Hibernate 3.1 and Annotations.

brian_of_fortent · **Joined:** Fri Aug 31, 2007 4:35 pm **Posts:** 4

Has anyone seen how to do this?

The only documentation I've seen is

http://www.hibernate.org/hib_docs/reference/en/html/xml.html

which uses a mapping file.

I'm about to the point of using JAXB instead... :-(

ashakarchi · **Joined:** Sat Jan 05, 2008 12:03 pm **Posts:** 1

Hey,

Anything new about this thread?

Thanks,

Asaf.

m.bergens · **Joined:** Wed Aug 08, 2007 11:22 pm **Posts:** 2

I've been struggling with this problem for a while but had to give up for the several reasons:

Memory. I could not figure out how to hook up SAX; DOM approach blows up memory really fast on large tables.
Formatting issues. Suppose you export your database on one server, import on another, with a different locale - then you get in trouble with date/time formats, number formats, encodings - all that information better be saved with the XML file and travel with it, or at least, with some accompanying file which isn't too good because you have to manage more than one piece.

It takes insane amount of time to find any relevant information in the hibernate documentation, even in those hibernate books many of which are misleading, and even at 800+ pages still very basic. In any case you are obliged to roll at least some of this infrastructure of your own, why not roll the whole thing out to be safe.