converting xml to java objects

[Christopher Au]

I would like to know whether it is possible to take a xml file and then get an java object equivalent. I have been able to use castor to generate classes from a schema generated from an xml file, however from what I can gather we cannot use those generated classes until they are compiled and placed into the classpath. If what I am asking is not possible I would like to know is how what alternatives do I have.

Thanks

Chris

[dennis zined]

you may want to take a look at xmlbeans.

[Rahul Bhattacharjee]

If you are saying that you need something that would give you objects straight away from xml , then its not possible.
You have to have class first before creating objects out of it.After all class is the blueprint from which you create object.

However you might automate the process to make java class using castor and then compiling those into classes and then jar those classes and using that in your application.

[Ugender Rekulampally]

Chris,

Here is some link which explains how to generate java objects from an XSD.
http://www.onjava.com/pub/a/onjava/2004/12/15/jaxb.html

This sample actually shows how to write data elements into the generated java objects and then producing XML document from those objects. So this part is called Marshalling. and I know you are asking about 'unmarshalling' and I couldnt find a better sample example on the web to give you a link but I did work on this part and I may be able to help you with that...

first get familiarize with the xjc stuff from above link (generating java objects from the schema) and see the above example (marshalling) and unmarshalling will be very simple. just other way around to marshalling example.


here is some sample code I wrote ..

try
      {

        JAXBContext jc = 
JAXBContext.newInstance( "generatedLogResultInputValues" );
        Unmarshaller u = jc.createUnmarshaller();
            
ByteArrayInputStream inputStream = new ByteArrayInputStream (logXMLstr.getBytes());
 
LogResultCodeInput logInput = 
                (LogResultCodeInput)u.unmarshal( inputStream );
 
generatedLogResultInputValues.ResultCode resultCode = logInput.getResultCode();

bigInt = resultCode.getRefObjectId();
if(bigInt != null)
refObjectId = bigInt.intValue();
 
refObjectType = resultCode.getRefObjectType();
if(refObjectType == null)
refObjectType = "";
 
source = resultCode.getSource();
if(source == null)
source = "";
}
 catch(JAXBException e)
    {
 log.error("In the logEvent JAXBException ", e);
    }

in the above code, "generatedLogResultInputValues" is the directory of the java classes which are generated by XSD.

and "logXMLstr" is the XML string that I am trying to convert into the Java objects...

Hope that helps. And let me know if I can help further.


Thanks,
Ugender
[ September 18, 2007: Message edited by: Ugender Rekulampally ]

[Rahul Bhattacharjee]

Originally posted by Ugender Rekulampally:
Chris,

Here is some link which explains how to generate java objects from an XSD.
http://www.onjava.com/pub/a/onjava/2004/12/15/jaxb.html

This sample actually shows how to write data elements into the generated java objects and then producing XML document from those objects. So this part is called Marshalling. and I know you are asking about 'unmarshalling' and I couldnt find a better sample example on the web to give you a link but I did work on this part and I may be able to help you with that...

first get familiarize with the xjc stuff from above link (generating java objects from the schema) and see the above example (marshalling) and unmarshalling will be very simple. just other way around to marshalling example.


here is some sample code I wrote ..

try
      {

        JAXBContext jc = 
JAXBContext.newInstance( "generatedLogResultInputValues" );
        Unmarshaller u = jc.createUnmarshaller();
            
ByteArrayInputStream inputStream = new ByteArrayInputStream (logXMLstr.getBytes());
 
LogResultCodeInput logInput = 
                (LogResultCodeInput)u.unmarshal( inputStream );
 
generatedLogResultInputValues.ResultCode resultCode = logInput.getResultCode();

bigInt = resultCode.getRefObjectId();
if(bigInt != null)
refObjectId = bigInt.intValue();
 
refObjectType = resultCode.getRefObjectType();
if(refObjectType == null)
refObjectType = "";
 
source = resultCode.getSource();
if(source == null)
source = "";
}
 catch(JAXBException e)
    {
 log.error("In the logEvent JAXBException ", e);
    }

in the above code, "generatedLogResultInputValues" is the directory of the java classes which are generated by XSD.

and "logXMLstr" is the XML string that I am trying to convert into the Java objects...

Hope that helps. And let me know if I can help further.


Thanks,
Ugender

[ September 18, 2007: Message edited by: Ugender Rekulampally ]

I guess Christopher is able to do all this and has asked for something else.

[Ugender Rekulampally]

OK. I thought he was looking for some alternatives..

If what I am asking is not possible I would like to know is how what alternatives do I have.

I actually did all that work what Chris was doing using just plain JAXB instead of Castor...anyways, it might be helpful to some one else who will just look for unmarshalling in Jaxb then.


Thanks,
Ugender

[Rahul Bhattacharjee]

May be you are correct.But reading the post made me feel that the original poster is aware of the marshalling stuff and wants to map an XML to objects without taking the pain to create objects out of classes and thats not possible.
Let the original poster clarify this. ;)