我从3个不同的客户端获得3个不同的xml输入：
客户端1的输入1（（命名空间前缀：ns2，名称空间URL：url1）
<ns2:myroot xmlns:ns2="url1">
<ns2:mydata>
<ns2:myrate>
GBP 800.55
</ns2:myrate>
</ns2:mydata>
</ns2:myroot>
客户端2的输入2（（命名空间前缀：
ns5，名称空间URL：url2）<ns5:myroot xmlns:ns5="url2">
<ns5:mydata>
<ns5:myrate>
THB 1000.70
</ns5:myrate>
</ns5:mydata>
</ns5:myroot>
客户端3的输入3（（命名空间前缀：
<empty>，名称空间URL：url3）<myroot xmlns="url3">
<mydata>
<myrate>
USD 955.25
</myrate>
</mydata>
</myroot>
它们全部3个具有相同的元素名称，但名称空间不同。因此，我写下了1个名为
MyRoot.java和MyData.java的类文件包：@XmlRootElement(name="myroot")
@XmlAccessorType(XmlAccessType.FIELD)
public class MyRoot
{ @XmlElement(name="mydata")
protected MyData mydata;
public MyData getMyData()
{ return mydata;
}
}
@XmlAccessorType(XmlAccessType.FIELD)
public class MyData
{ @XmlElement(name="myrate")
protected String myRate;
public String getMyRate()
{ return myRate;
}
}
这是我测试的方式：
public class Test {
public static void main(String[]ar){
for(String inputFileName:new String[]{"input3.xml","input2.xml","input1.xml"}){
try{
MyRoot myRoot = (MyRoot) JAXBContext.newInstance(MyRoot.class).createUnmarshaller().unmarshal(Test.class.getClassLoader().getResourceAsStream("data/xml/jaxb/varns/"+inputFileName));
System.out.println(myRoot.getMyData());
}catch (Exception e) {
e.printStackTrace();
}
}
}
}
我的问题是：
如果将
namespace="url3"添加到@XmlRootElement / @XmlElement，则得到：javax.xml.bind.UnmarshalException: unexpected element (uri:"url1", local:"myroot"). Expected elements are <{url3}myroot>和javax.xml.bind.UnmarshalException: unexpected element (uri:"url2", local:"myroot"). Expected elements are <{url3}myroot>如果将
namespace="url2"添加到@XmlRootElement / @XmlElement，则得到：javax.xml.bind.UnmarshalException: unexpected element (uri:"url1", local:"myroot"). Expected elements are <{url2}myroot>和javax.xml.bind.UnmarshalException: unexpected element (uri:"url3", local:"myroot"). Expected elements are <{url2}myroot>如果将
namespace="url1"添加到@XmlRootElement / @XmlElement，则得到：javax.xml.bind.UnmarshalException: unexpected element (uri:"url2", local:"myroot"). Expected elements are <{url1}myroot>和javax.xml.bind.UnmarshalException: unexpected element (uri:"url3", local:"myroot"). Expected elements are <{url1}myroot>我的问题是：
有什么办法可以使此代码适合于各种名称空间？
-------------------------------------------------
在Blaise Doughan的答案之后编辑：
-------------------------------------------------
由于我需要代码为每个输入使用不同的名称空间，因此我在代码中进行了以下更改：
使
NAMESPACE中的变量NamespaceFilter为非静态。将
Demo.java代码更改为具有名为MyRootUtils.java的方法的getMyRoot使用
JaxbContext.newInstance("url1")时，我发现没有这样的newInstance()以namespace-url作为参数。所以我将其更改为：newInstance(Myroot.class)。更改了
Test.java以适应新的类。MyRootUtils.java
package data.xml.jaxb.varns1;
import java.io.InputStream;
import javax.xml.bind.*;
import javax.xml.parsers.SAXParserFactory;
import org.xml.sax.*;
public class MyRootUtils {
public static MyRoot getMyRoot(String prefix,String url,InputStream xml) throws Exception {
// Create the JAXBContext
JAXBContext jc = JAXBContext.newInstance(MyRoot.class);//(MyRoot.class);
// Create the XMLFilter
XMLFilter filter = new NamespaceFilter(prefix,url);
// Set the parent XMLReader on the XMLFilter
filter.setParent(SAXParserFactory.newInstance().newSAXParser().getXMLReader());
// Set UnmarshallerHandler as ContentHandler on XMLFilter
Unmarshaller unmarshaller = jc.createUnmarshaller();
UnmarshallerHandler unmarshallerHandler = unmarshaller.getUnmarshallerHandler();
filter.setContentHandler(unmarshallerHandler);
// Parse the XML
filter.parse(new InputSource(xml));
return (MyRoot) unmarshallerHandler.getResult();
}
}
NamespaceFilter.java
package data.xml.jaxb.varns1;
import org.xml.sax.*;
import org.xml.sax.helpers.XMLFilterImpl;
public class NamespaceFilter extends XMLFilterImpl {
private final String NAMESPACE,PREFIX;
public NamespaceFilter(String prefix,String url) {
PREFIX=prefix;
NAMESPACE=url;
}
@Override
public void endElement(String uri, String localName, String qName)
throws SAXException {
System.out.println("::Into endElement(uri,localName,qName):: [uri: "+uri+"],[localName: "+localName+"],[qName: "+qName+"];");
super.endElement(NAMESPACE, localName, qName);
}
@Override
public void startElement(String uri, String localName, String qName,Attributes atts)
throws SAXException {
System.out.println("::Into startElement(uri,localName,qName,atts):: [uri: "+uri+"],[localName: "+localName+"],[qName: "+qName+"];");
super.startElement(NAMESPACE, localName, qName, atts);
}
@Override
public void startPrefixMapping(String prefix, String uri)
throws SAXException {
System.out.println(prefix+"="+uri);
super.startPrefixMapping(PREFIX, NAMESPACE);
}
@Override
public void endPrefixMapping(String prefix) throws SAXException {
super.endPrefixMapping(PREFIX);
}
}
Test.java
package data.xml.jaxb.varns1;
import java.io.InputStream;
public class Test {
public static void main(String[]ar){
String[] files={"input3.xml","input2.xml","input1.xml"};
String[] urls ={"url3","url2","url1"};
String[] prfs ={"","ns5","ns2"};
for(int i = 0 ; i < 3 ; ++i){
try{
String prefix=prfs[i];
String url = urls[i];
InputStream xml = Test.class.getClassLoader().getResourceAsStream("data/xml/jaxb/varns1/"+files[i]);
MyRoot myRoot = MyRootUtils.getMyRoot(prefix,url, xml);
System.out.println(myRoot.getMyData().getMyRate());
}catch (Exception e) {
System.err.println(e.getCause());
}
}
}
}
但是我仍然得到以下输出：
::Into startElement(uri,localName,qName,atts):: [uri: ],[localName: ],[qName: myroot];
javax.xml.bind.UnmarshalException: unexpected element (uri:"url3", local:"myroot"). Expected elements are <{}myroot>
::Into startElement(uri,localName,qName,atts):: [uri: ],[localName: ],[qName: ns5:myroot];
javax.xml.bind.UnmarshalException: unexpected element (uri:"url2", local:"ns5:myroot"). Expected elements are <{}myroot>
::Into startElement(uri,localName,qName,atts):: [uri: ],[localName: ],[qName: ns2:myroot];
javax.xml.bind.UnmarshalException: unexpected element (uri:"url1", local:"ns2:myroot"). Expected elements are <{}myroot>
这意味着缺少了一些东西。
这是其中一种异常（没有前缀的命名空间）的完整堆栈跟踪：
javax.xml.bind.UnmarshalException: unexpected element (uri:"url3", local:"myroot"). Expected elements are <{}myroot>
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext.handleEvent(UnmarshallingContext.java:648)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.Loader.reportError(Loader.java:236)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.Loader.reportError(Loader.java:231)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.Loader.reportUnexpectedChildElement(Loader.java:105)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext$DefaultRootLoader.childElement(UnmarshallingContext.java:1051)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext._startElement(UnmarshallingContext.java:484)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext.startElement(UnmarshallingContext.java:465)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.InterningXmlVisitor.startElement(InterningXmlVisitor.java:60)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.SAXConnector.startElement(SAXConnector.java:135)
at org.xml.sax.helpers.XMLFilterImpl.startElement(XMLFilterImpl.java:527)
at data.xml.jaxb.varns1.NamespaceFilter.startElement(NamespaceFilter.java:20)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.startElement(AbstractSAXParser.java:501)
at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.startElement(XMLDTDValidator.java:767)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanStartElement(XMLDocumentFragmentScannerImpl.java:1363)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$ContentDriver.scanRootElementHook(XMLDocumentScannerImpl.java:1315)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:3104)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDriver.next(XMLDocumentScannerImpl.java:921)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:647)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:511)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:808)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:737)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:119)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1205)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:522)
at org.xml.sax.helpers.XMLFilterImpl.parse(XMLFilterImpl.java:333)
at data.xml.jaxb.varns1.MyRootUtils.getMyRoot(MyRootUtils.java:31)
at data.xml.jaxb.varns1.Test.main(Test.java:15)
Caused by: javax.xml.bind.UnmarshalException: unexpected element (uri:"url3", local:"myroot"). Expected elements are <{}myroot>
... 27 more
这是另一个堆栈跟踪（带前缀的命名空间）：
javax.xml.bind.UnmarshalException: unexpected element (uri:"url2", local:"ns5:myroot"). Expected elements are <{}myroot>
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext.handleEvent(UnmarshallingContext.java:648)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.Loader.reportError(Loader.java:236)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.Loader.reportError(Loader.java:231)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.Loader.reportUnexpectedChildElement(Loader.java:105)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext$DefaultRootLoader.childElement(UnmarshallingContext.java:1051)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext._startElement(UnmarshallingContext.java:484)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext.startElement(UnmarshallingContext.java:465)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.InterningXmlVisitor.startElement(InterningXmlVisitor.java:60)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.SAXConnector.startElement(SAXConnector.java:135)
at org.xml.sax.helpers.XMLFilterImpl.startElement(XMLFilterImpl.java:527)
at data.xml.jaxb.varns1.NamespaceFilter.startElement(NamespaceFilter.java:20)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.startElement(AbstractSAXParser.java:501)
at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.startElement(XMLDTDValidator.java:767)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanStartElement(XMLDocumentFragmentScannerImpl.java:1363)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$ContentDriver.scanRootElementHook(XMLDocumentScannerImpl.java:1315)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:3104)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDriver.next(XMLDocumentScannerImpl.java:921)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:647)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:511)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:808)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:737)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:119)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1205)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:522)
at org.xml.sax.helpers.XMLFilterImpl.parse(XMLFilterImpl.java:333)
at data.xml.jaxb.varns1.MyRootUtils.getMyRoot(MyRootUtils.java:31)
at data.xml.jaxb.varns1.Test.main(Test.java:15)
Caused by: javax.xml.bind.UnmarshalException: unexpected element (uri:"url2", local:"ns5:myroot"). Expected elements are <{}myroot>
... 27 more
添加
namespace="url1"也没有用，因为我仍然有相同的异常堆栈。输出：（无
namespace="url1"）::Into startElement(uri,localName,qName,atts):: [uri: ],[localName: ],[qName: ns5:myroot];
javax.xml.bind.UnmarshalException: unexpected element (uri:"url2", local:"ns5:myroot"). Expected elements are <{}myroot>
输出：（带
namespace="url1"）::Into startElement(uri,localName,qName,atts):: [uri: ],[localName: ],[qName: ns2:myroot];
javax.xml.bind.UnmarshalException: unexpected element (uri:"url1", local:"ns2:myroot"). Expected elements are <{url1}myroot>
显示名称空间解析尚未完成。
最后，我进行了2项更改：
我在
.replace("old-string","new-string")中使用了String类的NamespaceFilter.java方法来减少qName（完全限定的元素名称），如下所示：super.endElement(NAMESPACE, localName, qName);变成：
super.endElement("", localName, qName.replace(PREFIX+":", ""));super.startElement(NAMESPACE, localName, qName, atts);变成：
super.startElement("", localName, qName.replace(PREFIX+":", ""), atts);NamespaceFilter.java的代码：package data.xml.jaxb.varns1;
import org.xml.sax.*;
import org.xml.sax.helpers.XMLFilterImpl;
public class NamespaceFilter extends XMLFilterImpl {
private final String NAMESPACE,PREFIX;
public NamespaceFilter(String prefix,String url) {
PREFIX=prefix;
NAMESPACE=url;
}
@Override
public void endElement(String uri, String localName, String qName)
throws SAXException {
System.out.println("::Into endElement(uri,localName,qName):: [uri: "+uri+"],[localName: "+localName+"],[qName: "+qName+"];");
super.endElement("", localName, qName.replace(PREFIX+":", ""));
}
@Override
public void startElement(String uri, String localName, String qName,Attributes atts)
throws SAXException {
System.out.println("::Into startElement(uri,localName,qName,atts):: [uri: "+uri+"],[localName: "+localName+"],[qName: "+qName+"];");
super.startElement("", localName, qName.replace(PREFIX+":", ""), atts);
}
@Override
public void startPrefixMapping(String prefix, String uri)
throws SAXException {
System.out.println(prefix+"="+uri);
super.startPrefixMapping(PREFIX, NAMESPACE);
}
@Override
public void endPrefixMapping(String prefix) throws SAXException {
super.endPrefixMapping(PREFIX);
}
}
现在的输出是：
::Into startElement(uri,localName,qName,atts):: [uri: ],[localName: ],[qName: myroot];
::Into startElement(uri,localName,qName,atts):: [uri: ],[localName: ],[qName: mydata];
::Into startElement(uri,localName,qName,atts):: [uri: ],[localName: ],[qName: myrate];
::Into endElement(uri,localName,qName):: [uri: ],[localName: ],[qName: myrate];
::Into endElement(uri,localName,qName):: [uri: ],[localName: ],[qName: mydata];
::Into endElement(uri,localName,qName):: [uri: ],[localName: ],[qName: myroot];
USD 955.25
::Into startElement(uri,localName,qName,atts):: [uri: ],[localName: ],[qName: ns5:myroot];
::Into startElement(uri,localName,qName,atts):: [uri: ],[localName: ],[qName: ns5:mydata];
::Into startElement(uri,localName,qName,atts):: [uri: ],[localName: ],[qName: ns5:myrate];
::Into endElement(uri,localName,qName):: [uri: ],[localName: ],[qName: ns5:myrate];
::Into endElement(uri,localName,qName):: [uri: ],[localName: ],[qName: ns5:mydata];
::Into endElement(uri,localName,qName):: [uri: ],[localName: ],[qName: ns5:myroot];
THB 1000.70
::Into startElement(uri,localName,qName,atts):: [uri: ],[localName: ],[qName: ns2:myroot];
::Into startElement(uri,localName,qName,atts):: [uri: ],[localName: ],[qName: ns2:mydata];
::Into startElement(uri,localName,qName,atts):: [uri: ],[localName: ],[qName: ns2:myrate];
::Into endElement(uri,localName,qName):: [uri: ],[localName: ],[qName: ns2:myrate];
::Into endElement(uri,localName,qName):: [uri: ],[localName: ],[qName: ns2:mydata];
::Into endElement(uri,localName,qName):: [uri: ],[localName: ],[qName: ns2:myroot];
GBP 800.55
但是，这引起了一些担忧：
完全忽略命名空间。
每次有
String.replace()和startElement()时都调用endElement()这让我想想，这种用于变量命名空间的方法是否应该可以接受。
如果可以采取任何措施来改进此代码，那么我请社区在答案/评论中提及它，并帮助消除这种可能有缺陷的方法。
最佳答案
从主命名空间处理XML
对于直接与您在Java模型中映射到的名称空间相对应的任何XML，可以正常将其编组/取消编组。
从辅助命名空间处理XML
解组
您可以在解组时应用SAX XMLFilter，当您处理与名称空间为url2的模式相对应的XML文档时，它看起来好像与名称空间为url1的模式相对应。
import org.xml.sax.*;
import org.xml.sax.helpers.XMLFilterImpl;
public class NamespaceFilter extends XMLFilterImpl {
private static final String NAMESPACE = "url1";
@Override
public void endElement(String uri, String localName, String qName)
throws SAXException {
super.endElement(NAMESPACE, localName, qName);
}
@Override
public void startElement(String uri, String localName, String qName,
Attributes atts) throws SAXException {
super.startElement(NAMESPACE, localName, qName, atts);
}
}
示范代码
这是一些示例代码，演示如何应用
XMLFilter。import javax.xml.bind.*;
import javax.xml.parsers.*;
import org.xml.sax.*;
public class Demo {
public static void main(String[] args) throws Exception {
// Create the JAXBContext
JAXBContext jc = JAXBContext.newInstance("url1");
// Create the XMLFilter
XMLFilter filter = new NamespaceFilter();
// Set the parent XMLReader on the XMLFilter
SAXParserFactory spf = SAXParserFactory.newInstance();
SAXParser sp = spf.newSAXParser();
XMLReader xr = sp.getXMLReader();
filter.setParent(xr);
// Set UnmarshallerHandler as ContentHandler on XMLFilter
Unmarshaller unmarshaller = jc.createUnmarshaller();
UnmarshallerHandler unmarshallerHandler = unmarshaller
.getUnmarshallerHandler();
filter.setContentHandler(unmarshallerHandler);
// Parse the XML
InputSource xml = new InputSource("input.xml");
filter.parse(xml);
Object result = unmarshallerHandler.getResult();
}
}