CODEWITHSUNDEEP
javaxmljaxb
T Soares
T Soares

Reputation: 81

JAXB - unmarshal XML exception

I've tried to read a big xml file (something like 500MB). First of all, I used xjc with the XSD file of my XML. All classes were generated as expected. Trying to read the file I've got this error: javax.xml.bind.UnmarshalException: unexpected element.

Here is my code:

(...)

JAXBContext context = JAXBContext.newInstance("br.com.mypackage");
Unmarshaller unmarshaller = context.createUnmarshaller();
File f = new File("src/files/MyHuge.CNX");
XMLInputFactory inputFactory = XMLInputFactory.newInstance();
InputStream in = new FileInputStream(f);
XMLEventReader eventReader = inputFactory.createXMLEventReader(in);
Person p = null;
int count = 0;
while (eventReader.hasNext()) {
   XMLEvent event = eventReader.nextEvent();
   if (event.isStartElement()) {
      StartElement startElement = event.asStartElement();
      if (startElement.getName().getLocalPart() == ("person")) {
         p = (Person) unmarshaller.unmarshal(eventReader);
      }
   }
}

The problem is in the unmarshal operation. 

Caused by: javax.xml.bind.UnmarshalException: unexpected element (uri:"", local:"identification"). Expected elements are <{}messageAll>

I used this link as example to make my own code: JAXB - unmarshal OutOfMemory: Java Heap Space

Someone has a clue to do it? All that I want now is to read a huge XML file without unmarshal the external object of XML (java heap space problem) and without reading tag by tag getting the respective value, a slow and monkey code (not the monkeys of Rise of the Planet of the Apes). :P

Many thanks.

Upvotes: 2

Views: 4273

Answers (2)

T Soares
T Soares

Reputation: 81

I solved the problem with this code bellow:

public List<Person> testeUnmarshal() {
  List<Person> people = new ArrayList<Person>();
  Person p = null;
  try {
    JAXBContext context = JAXBContext.newInstance(Person.class);
    Unmarshaller unmarshaller = context.createUnmarshaller();
    File f = new File(FILE_PATH);
    XMLInputFactory inputFactory = XMLInputFactory.newInstance();
    XMLEventReader eventReader = inputFactory.createXMLEventReader(new FileInputStream(f));
    while (eventReader.hasNext()) {
      XMLEvent event = eventReader.peek();
      if (event.isStartElement()) {
        StartElement start = event.asStartElement();
    if (start.getName().getLocalPart() == "person")) {
          JAXBElement<Person> jax_b = unmarshaller.unmarshal(eventReader, Person.class);
      p = jax_b.getValue();
    }
      }
      eventReader.next();
    }
  } catch (Exception e) {
  }
  return persons;
}

I can control the amount of objects in memory using counts inside a loop (for 1000 Persons commit in database).

Upvotes: 2

Donal Fellows
Donal Fellows

Reputation: 137567

I'm guessing that the problem is you've already consumed the <person> from the event stream so JAXB doesn't know what it is doing; it needs that element to be there so it can build the object. Thus, I suspect you need to peek the stream to decide whether to consume (and discard) or to unmarshal:

while (eventReader.hasNext()) {
   XMLEvent event = eventReader.peek();
   if (event.isStartElement()) {
      StartElement startElement = event.asStartElement();
      if (startElement.getName().getLocalPart() == ("person")) {
         p = (Person) unmarshaller.unmarshal(eventReader);
         continue; // Assume you've done something with p; go round loop again
      }
   }
   eventReader.nextElement(); // Discard...
}

Upvotes: 2

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