我正在使用JAXB的partial-unmarshalling示例,但我无法解组没有@XmlRootElement标签的不在根级别的XML元素。在我的示例中,我尝试读取shipTo元素而不是purchaseOrder元素。
通常我会使用JAXBElement unmarshal(Source source,Class declaredType),但由于示例使用UnmarshallerHandler和XMLFilterImpl,我不知道该告诉Jaxb使用哪个类。
我的错误信息是:javax.xml.bind.UnmarshalException:意外元素(uri:“”,local:“shipTo”)。预期元素是<{}comment>,<{}purchaseOrder>,<{}purchaseOrders> 我搜索了很多谷歌,但还没有找到有用的东西。
这是JaxB-Webpage上的示例代码:
Main.java
通常我会使用JAXBElement unmarshal(Source source,Class declaredType),但由于示例使用UnmarshallerHandler和XMLFilterImpl,我不知道该告诉Jaxb使用哪个类。
我的错误信息是:javax.xml.bind.UnmarshalException:意外元素(uri:“”,local:“shipTo”)。预期元素是<{}comment>,<{}purchaseOrder>,<{}purchaseOrders> 我搜索了很多谷歌,但还没有找到有用的东西。
这是JaxB-Webpage上的示例代码:
Main.java
public class Main {
public static void main( String[] args ) throws Exception {
// create JAXBContext for the primer.xsd
JAXBContext context = JAXBContext.newInstance("primer");
// create a new XML parser
SAXParserFactory factory = SAXParserFactory.newInstance();
factory.setNamespaceAware(true);
XMLReader reader = factory.newSAXParser().getXMLReader();
// prepare a Splitter
Splitter splitter = new Splitter(context);
// connect two components
reader.setContentHandler(splitter);
for( int i=0; i<args.length; i++ ) {
// parse all the documents specified via the command line.
// note that XMLReader expects an URL, not a file name.
// so we need conversion.
reader.parse(new File(args[i]).toURL().toExternalForm());
}
}
}
Splitter.java
public class Splitter extends XMLFilterImpl {
public Splitter( JAXBContext context ) {
this.context = context;
}
/**
* We will create unmarshallers from this context.
*/
private final JAXBContext context;
public void startElement(String namespaceURI, String localName, String qName, Attributes atts)
throws SAXException {
if( depth!= 0 ) {
// we are in the middle of forwarding events.
// continue to do so.
depth++;
super.startElement(namespaceURI, localName, qName, atts);
return;
}
if( namespaceURI.equals("") && localName.equals("purchaseOrder") ) {
// start a new unmarshaller
Unmarshaller unmarshaller;
try {
unmarshaller = context.createUnmarshaller();
} catch( JAXBException e ) {
// there's no way to recover from this error.
// we will abort the processing.
throw new SAXException(e);
}
unmarshallerHandler = unmarshaller.getUnmarshallerHandler();
// set it as the content handler so that it will receive
// SAX events from now on.
setContentHandler(unmarshallerHandler);
// fire SAX events to emulate the start of a new document.
unmarshallerHandler.startDocument();
unmarshallerHandler.setDocumentLocator(locator);
Enumeration e = namespaces.getPrefixes();
while( e.hasMoreElements() ) {
String prefix = (String)e.nextElement();
String uri = namespaces.getURI(prefix);
unmarshallerHandler.startPrefixMapping(prefix,uri);
}
String defaultURI = namespaces.getURI("");
if( defaultURI!=null )
unmarshallerHandler.startPrefixMapping("",defaultURI);
super.startElement(namespaceURI, localName, qName, atts);
// count the depth of elements and we will know when to stop.
depth=1;
}
}
public void endElement(String namespaceURI, String localName, String qName) throws SAXException {
// forward this event
super.endElement(namespaceURI, localName, qName);
if( depth!=0 ) {
depth--;
if( depth==0 ) {
// just finished sending one chunk.
// emulate the end of a document.
Enumeration e = namespaces.getPrefixes();
while( e.hasMoreElements() ) {
String prefix = (String)e.nextElement();
unmarshallerHandler.endPrefixMapping(prefix);
}
String defaultURI = namespaces.getURI("");
if( defaultURI!=null )
unmarshallerHandler.endPrefixMapping("");
unmarshallerHandler.endDocument();
// stop forwarding events by setting a dummy handler.
// XMLFilter doesn't accept null, so we have to give it something,
// hence a DefaultHandler, which does nothing.
setContentHandler(new DefaultHandler());
// then retrieve the fully unmarshalled object
try {
JAXBElement<PurchaseOrderType> result =
(JAXBElement<PurchaseOrderType>)unmarshallerHandler.getResult();
// process this new purchase order
process(result.getValue());
} catch( JAXBException je ) {
// error was found during the unmarshalling.
// you can either abort the processing by throwing a SAXException,
// or you can continue processing by returning from this method.
System.err.println("unable to process an order at line "+
locator.getLineNumber() );
return;
}
unmarshallerHandler = null;
}
}
}
public void process( PurchaseOrderType order ) {
System.out.println("this order will be shipped to "
+ order.getShipTo().getName() );
}
/**
* Remembers the depth of the elements as we forward
* SAX events to a JAXB unmarshaller.
*/
private int depth;
/**
* Reference to the unmarshaller which is unmarshalling
* an object.
*/
private UnmarshallerHandler unmarshallerHandler;
/**
* Keeps a reference to the locator object so that we can later
* pass it to a JAXB unmarshaller.
*/
private Locator locator;
public void setDocumentLocator(Locator locator) {
super.setDocumentLocator(locator);
this.locator = locator;
}
/**
* Used to keep track of in-scope namespace bindings.
*
* For JAXB unmarshaller to correctly unmarshal documents, it needs
* to know all the effective namespace declarations.
*/
private NamespaceSupport namespaces = new NamespaceSupport();
public void startPrefixMapping(String prefix, String uri) throws SAXException {
namespaces.pushContext();
namespaces.declarePrefix(prefix,uri);
super.startPrefixMapping(prefix, uri);
}
public void endPrefixMapping(String prefix) throws SAXException {
namespaces.popContext();
super.endPrefixMapping(prefix);
}
}
Primer.xsd
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<xsd:annotation>
<xsd:documentation xml:lang="en">
Purchase order schema for Example.com.
Copyright 2000 Example.com. All rights reserved.
</xsd:documentation>
</xsd:annotation>
<xsd:element name="purchaseOrders">
<xsd:complexType>
<xsd:sequence>
<xsd:element ref="purchaseOrder" minOccurs="0" maxOccurs="unbounded"/>
</xsd:sequence>
</xsd:complexType>
</xsd:element>
<xsd:element name="purchaseOrder" type="PurchaseOrderType"/>
<xsd:element name="comment" type="xsd:string"/>
<xsd:complexType name="PurchaseOrderType">
<xsd:sequence>
<xsd:element name="shipTo" type="USAddress"/>
<xsd:element name="billTo" type="USAddress"/>
<xsd:element ref="comment" minOccurs="0"/>
<xsd:element name="items" type="Items"/>
</xsd:sequence>
<xsd:attribute name="orderDate" type="xsd:date"/>
</xsd:complexType>
<xsd:complexType name="USAddress">
<xsd:sequence>
<xsd:element name="name" type="xsd:string"/>
<xsd:element name="street" type="xsd:string"/>
<xsd:element name="city" type="xsd:string"/>
<xsd:element name="state" type="xsd:string"/>
<xsd:element name="zip" type="xsd:decimal"/>
</xsd:sequence>
<xsd:attribute name="country" type="xsd:NMTOKEN"
fixed="US"/>
</xsd:complexType>
<xsd:complexType name="Items">
<xsd:sequence>
<xsd:element name="item" minOccurs="0" maxOccurs="unbounded">
<xsd:complexType>
<xsd:sequence>
<xsd:element name="productName" type="xsd:string"/>
<xsd:element name="quantity">
<xsd:simpleType>
<xsd:restriction base="xsd:positiveInteger">
<xsd:maxExclusive value="100"/>
</xsd:restriction>
</xsd:simpleType>
</xsd:element>
<xsd:element name="USPrice" type="xsd:decimal"/>
<xsd:element ref="comment" minOccurs="0"/>
<xsd:element name="shipDate" type="xsd:date" minOccurs="0"/>
</xsd:sequence>
<xsd:attribute name="partNum" type="SKU" use="required"/>
</xsd:complexType>
</xsd:element>
</xsd:sequence>
</xsd:complexType>
<!-- Stock Keeping Unit, a code for identifying products -->
<xsd:simpleType name="SKU">
<xsd:restriction base="xsd:string">
<xsd:pattern value="\d{3}-[A-Z]{2}"/>
</xsd:restriction>
</xsd:simpleType>
</xsd:schema>
test.xml
<purchaseOrders>
<!-- 1st -->
<purchaseOrder orderDate="1999-10-20">
<shipTo country="US">
<name>Alice Smith</name>
<street>123 Maple Street</street>
<city>Cambridge</city>
<state>MA</state>
<zip>12345</zip>
</shipTo>
<billTo country="US">
<name>Robert Smith</name>
<street>8 Oak Avenue</street>
<city>Cambridge</city>
<state>MA</state>
<zip>12345</zip>
</billTo>
<items/>
</purchaseOrder>
</purchaseOrders>