SAXParseException: Parsing large XML files with JAXB and StAX

[Sverre Moe]

I have build my own XML schema for invoice events and are using JAXB2 to parse an XML document based upon this XML schema.

The following piece of code works fine, but does not handle very large files:

        Path path = Paths.get("invoiceEvents.xml");
        try {
            Path schemaFile = Paths.get("src/main/resources/invoice-invoiceevents-1.0.xsd");
            SchemaFactory sf = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
            Schema faktSchema = sf.newSchema(schemaFile.toFile());
            
            JAXBContext jaxbContext = JAXBContext.newInstance(InvoiceEvents.class);
            Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
            jaxbUnmarshaller.setSchema(faktSchema);
            
            InvoiceEvents events = (InvoiceEvents) jaxbUnmarshaller.unmarshal(path.toFile());
            List<InvoiceEvent> eventsList = events.getFakthendelse();
        } catch (UnmarshalException e2) {
            e2.printStackTrace();
        } catch (JAXBException e) {
            e.printStackTrace();
        }

Then I tried using StAX with JAXB in order to stream read the XML file.

Soluton1:

        Path path = Paths.get("invoiceEvents.xml");
        try {
            Path schemaFile = Paths.get("src/main/resources/invoice-invoiceevents-1.0.xsd");
            SchemaFactory sf = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
            Schema faktSchema = sf.newSchema(schemaFile.toFile());
            
            JAXBContext jaxbContext = JAXBContext.newInstance(InvoiceEvent.class);
            Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
            jaxbUnmarshaller.setSchema(faktSchema);
            
            XMLInputFactory xif = XMLInputFactory.newInstance();
            FileReader fileReader = new FileReader(path.toFile());
            XMLStreamReader xsr = xif.createXMLStreamReader(fileReader);
            xsr.nextTag();
            
            while (xsr.nextTag() == XMLStreamConstants.START_ELEMENT) {
                InvoiceEvent event = (InvoiceEvent) jaxbUnmarshaller.unmarshal(xsr);
            }
        } catch (UnmarshalException e2) {
            e2.printStackTrace();
        } catch (JAXBException e) {
            e.printStackTrace();
        }

Solution2:

        Path path = Paths.get("invoiceEvents.xml");
        try {
            Path schemaFile = Paths.get("src/main/resources/invoice-invoiceevents-1.0.xsd");
            SchemaFactory sf = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
            Schema faktSchema = sf.newSchema(schemaFile.toFile());
            
            JAXBContext jaxbContext = JAXBContext.newInstance(InvoiceEvent.class);
            Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
            jaxbUnmarshaller.setSchema(faktSchema);
            
            XMLInputFactory xif = XMLInputFactory.newInstance();
            FileReader fileReader = new FileReader(path.toFile());
            XMLEventReader xer = xif.createXMLEventReader(fileReader);
            EventFilter filter = new EventFilter() {
                public boolean accept(XMLEvent event) {
                    return event.isStartElement();
                }
            };
            XMLEventReader xfer = xif.createFilteredReader(xer, filter);
            
            StartElement e = (StartElement) xfer.nextEvent();
            while (xfer.peek() != null) {
                 Object o = jaxbUnmarshaller.unmarshal(xer);
                 if (o instanceof Fakthendelse) {
                     InvoiceEvent event = (InvoiceEvent) o;
                 }
            }
        } catch (UnmarshalException e2) {
            e2.printStackTrace();
        } catch (JAXBException e) {
            e.printStackTrace();
        }

Both solutions with StAX gives me the following error:

javax.xml.bind.UnmarshalException
- with linked exception:
[org.xml.sax.SAXParseException; lineNumber: 3; columnNumber: 15; cvc-elt.1: Cannot find the declaration of element 'invoiceEvent'.]
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.handleStreamException(UnmarshallerImpl.java:419)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(UnmarshallerImpl.java:356)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal(UnmarshallerImpl.java:326)
at Invoice.main(Invoice.java:90)
Caused by: org.xml.sax.SAXParseException; lineNumber: 3; columnNumber: 15; cvc-elt.1: Cannot find the declaration of element 'invoiceEvent'.

My XML Schema file:
<?xml version="1.0"?> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"> <xs:element name="invoiceEvents"> <xs:complexType> <xs:sequence> <xs:element name="invoiceEvent" type="InvoiceEvent" maxOccurs="unbounded" /> </xs:sequence> </xs:complexType> </xs:element> <xs:complexType name="InvoiceEvent"> <xs:sequence> <xs:element .... /> </xs:sequence> </xs:complexType>

The first few lines of my XML file:
<?xml version="1.0" encoding="UTF-8"?> <invoiceEvents xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://myURL.com/schema/invoice http://myURL.com/schema/invoice/invoice-invoiceevent-1.0.xsd"> <invoiceEvent> ....

[g tsuji]

Haven't digested the message at all. But a quick browse over see this.

xsi:noNamespaceSchemaLocation="http://myURL.com/schema/invoice http://myURL.com/schema/invoice/invoice-invoiceevent-1.0.xsd"

It is an incorrect xsi:noNamespaceSchemaLocation attribute. It should look more like this.
xsi:noNamespaceSchemaLocation="http://myURL.com/schema/invoice/invoice-invoiceevent-1.0.xsd"

[Sverre Moe]

g tsuji wrote:Haven't digested the message at all. But a quick browse over see this.

xsi:noNamespaceSchemaLocation="http://myURL.com/schema/invoice http://myURL.com/schema/invoice/invoice-invoiceevent-1.0.xsd"

It is an incorrect xsi:noNamespaceSchemaLocation attribute. It should look more like this.
xsi:noNamespaceSchemaLocation="http://myURL.com/schema/invoice/invoice-invoiceevent-1.0.xsd"

I have updated my XML file accordingly.

Found the problem: When using StAX I needed to make a change to my XML Schema.
<?xml version="1.0"?> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"> <xs:element name="invoiceEvents"> <xs:complexType> <xs:sequence> <xs:element ref="invoiceEvent" maxOccurs="unbounded" /> </xs:sequence> </xs:complexType> </xs:element> <xs:element name="invoiceEvent"> <xs:complexType> <xs:sequence> <xs:element .... /> </xs:sequence> </xs:complexType> </xs:element>
Then I could use my XML Schema with both JAXB collecting the entire InvoiceEvents, and StAX and streaming single InvoiceEvent.

Though, solution1 and 2 worked I would like to know whats the difference in using XMLEventReader and XMLStreamReader.