9
IM在一個Java項目，我需要從一個XML文件中讀取一些對象，做一些處理，這將改變object's atributes然後寫對象到另一個XML文件的工作。爲此，我使用JAXB以其編組和解組的能力，他們每個人的方法，像這樣：JAXB XML對象沒有命名空間前綴編組
private MyObject unmarshallXMLFile(String file) {
MyObject t=null;
try {
jc = JAXBContext.newInstance("foo.bar");
Unmarshaller unmarshaller = jc.createUnmarshaller();
SchemaFactory sf = SchemaFactory.newInstance(javax.xml.XMLConstants.W3C_XML_SCHEMA_NS_URI);
unmarshaller.setSchema(sf.newSchema(new File("MySchema.xsd")));
t = (Task) unmarshaller.unmarshal(new File(file));
} catch (JAXBException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
}
return t;
}
private void marshallXMLFile(String file) {
task.setReplay(Boolean.TRUE);
Marshaller marshaller;
try {
marshaller = jc.createMarshaller();
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, new Boolean(true));
marshaller.marshal(task, new FileOutputStream(file));
} catch (JAXBException e) {
e.printStackTrace();
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
的問題是自動生成的命名空間前綴，如NS2或NS3不斷出現在輸出文件，然後當我想重用與unmarshallXMLFile方法這個文件（我會再次使用該輸出文件作爲輸入以後）就不會得到有效的對抗模式，並拋出一個org.xml.sax.SAXParseException。下面是我寫的文件：
XML模式：MySchema.xsd
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<schema xmlns="http://www.w3.org/2001/XMLSchema" targetNamespace="http://www.example.org/MySchema"
xmlns:spm="http://www.example.org/MySchema"
elementFormDefault="qualified"
attributeFormDefault="qualified">
<element name="task" >
<complexType>
<sequence>
<element name="replay" type="boolean" default="false"/>
<element name="threads" type="spm:spThread" maxOccurs="unbounded" minOccurs="1" />
</sequence>
</complexType>
</element>
<complexType name="spThread">
<sequence>
<element name="SPThreadID" type="int" />
<element name="durtime" minOccurs="0" default="0">
<simpleType>
<restriction base="int">
<minInclusive value="0" />
</restriction>
</simpleType>
</element>
<element name="minexecutions" minOccurs="0" default="0">
<simpleType>
<restriction base="int">
<minInclusive value="0" />
</restriction>
</simpleType>
</element>
<element name="numThreads" type="int" />
<element name="procedures" type="spm:procedure" minOccurs="1"
maxOccurs="unbounded" />
</sequence>
</complexType>
<complexType name="procedure">
<sequence>
<element name="id" type="int" minOccurs="1" />
<element name="name" type="string" minOccurs="1" />
<element name="weight" minOccurs="1">
<simpleType>
<restriction base="int">
<minInclusive value="0" />
<maxInclusive value="100" />
</restriction>
</simpleType>
</element>
<element name="parameterPool" type="spm:parameter" nillable="true"
minOccurs="0" maxOccurs="unbounded" />
</sequence>
</complexType>
<complexType name="parameter">
<sequence>
<element name="name" type="string" minOccurs="1" />
<element name="dataType" type="spm:parameterDataType" default="integer"/>
<element name="parmType" type="spm:parameterType" default="in"
minOccurs="0" />
<element name="minValue" type="string"/>
<element name="maxValue" type="string"/>
<element name="value" type="string"/>
</sequence>
</complexType>
<simpleType name="parameterDataType">
<restriction base="string">
<enumeration value="integer" />
<enumeration value="varchar" />
<enumeration value="char" />
</restriction>
</simpleType>
<simpleType name="parameterType">
<restriction base="string">
<enumeration value="in" />
<enumeration value="out" />
<enumeration value="in_out" />
</restriction>
</simpleType>
</schema>
輸入文件：
<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<task xmlns="http://www.example.org/MySchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.example.org/MySchema MySchema.xsd ">
<replay>true</replay>
<threads>
<SPThreadID>0</SPThreadID>
<durtime>10</durtime>
<minexecutions>2</minexecutions>
<numThreads>3</numThreads>
<procedures>
<id>1</id>
<name>run</name>
<weight>15</weight>
<parameterPool>
<name>energy</name>
<dataType>integer</dataType>
<parmType>in</parmType>
<minValue>10</minValue>
<maxValue>50</maxValue>
<value>11</value>
</parameterPool>
<parameterPool>
<name>speed</name>
<dataType>integer</dataType>
<parmType>in</parmType>
<minValue>12</minValue>
<maxValue>80</maxValue>
<value>13</value>
</parameterPool>
</procedures>
</threads>
</task>
輸出文件（不加任何處理責任：剛剛解組，並與方法編組回前面提到）
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ns2:task xmlns="http://www.example.org/MySchema" xmlns:ns2="http://www.example.org/MySchema.xsd">
<replay>true</replay>
<threads>
<SPThreadID>0</SPThreadID>
<durtime>10</durtime>
<minexecutions>2</minexecutions>
<numThreads>3</numThreads>
<procedures>
<id>1</id>
<name>run</name>
<weight>15</weight>
<parameterPool>
<name>energy</name>
<dataType>integer</dataType>
<parmType>in</parmType>
<minValue>10</minValue>
<maxValue>50</maxValue>
<value>11</value>
</parameterPool>
<parameterPool>
<name>speed</name>
<dataType>integer</dataType>
<parmType>in</parmType>
<minValue>12</minValue>
<maxValue>80</maxValue>
<value>13</value>
</parameterPool>
</procedures>
</threads>
</ns2:task>
異常（當再次使用輸出文件時S上輸入）：
javax.xml.bind.UnmarshalException
- with linked exception:
[org.xml.sax.SAXParseException: cvc-elt.1: The declaration of the element'ns3:task' could not be found.]
at javax.xml.bind.helpers.AbstractUnmarshallerImpl.createUnmarshalException(AbstractUnmarshallerImpl.java:326)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.createUnmarshalException(UnmarshallerImpl.java:500)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(UnmarshallerImpl.java:206)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal(UnmarshallerImpl.java:175)
at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:148)
at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:153)
at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:162)
at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:180)
at Test.main(Test.java:48)
Caused by: org.xml.sax.SAXParseException: cvc-elt.1: The declaration of the element'ns3:task' could not be found.
at org.apache.xerces.util.ErrorHandlerWrapper.createSAXParseException(Unknown Source)
at org.apache.xerces.util.ErrorHandlerWrapper.error(Unknown Source)
at org.apache.xerces.impl.XMLErrorReporter.reportError(Unknown Source)
at org.apache.xerces.impl.XMLErrorReporter.reportError(Unknown Source)
at org.apache.xerces.impl.xs.XMLSchemaValidator.handleStartElement(Unknown Source)
at org.apache.xerces.impl.xs.XMLSchemaValidator.startElement(Unknown Source)
at org.apache.xerces.jaxp.validation.XMLSchemaValidatorHandler.startElement(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.ValidatingUnmarshaller.startElement(ValidatingUnmarshaller.java:85)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.SAXConnector.startElement(SAXConnector.java:113)
at org.apache.xerces.parsers.AbstractSAXParser.startElement(Unknown Source)
at org.apache.xerces.impl.XMLNSDocumentScannerImpl.scanStartElement(Unknown Source)
at org.apache.xerces.impl.XMLNSDocumentScannerImpl$NSContentDispatcher.scanRootElementHook(Unknown Source)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(Unknown Source)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(UnmarshallerImpl.java:202)
... 6 more
從來就一直唸叨的主題，並試圖解答相關的負荷，但他們都不似乎去掉前綴。我走到低谷這個guide但JAXB我使用不支持NamespacePrefixMapper的版本。我嘗試使用註釋here來配置前綴，但不起作用。
也許有一種擺脫這個命名空間前綴的方法：我找到的所有論壇，答案和討論都是關於自定義這個前綴的，我只是想擺脫它們。但不知怎的，它讓我覺得我在輸入文件和模式中都缺少一些東西。他們寫得好嗎？我要說的是那裏的問題，因爲這是我第一次在這個深度與XML和XSD工作，什麼從來就做了只基於什麼從來就在網上找到。有關改進xml和xsd設計的任何提示將不勝感激
我應該在輸入文件中還是在架構中使用某種前綴，以便JAXB框架在編組時不會生成隨機前綴？
在此先感謝，我希望你們能幫助我。
-
非常感謝您的回答。這樣我就可以使用NamespacePrefixMapper。然而，當我使用它，我的代碼不斷拋出異常，當我運行它：
Exception in thread "main" java.util.MissingResourceException: Can't find bundle for base name javax.xml.bind.Messages, locale de_DE
at java.util.ResourceBundle.throwMissingResourceException(ResourceBundle.java:863)
at java.util.ResourceBundle.getBundleImpl(ResourceBundle.java:832)
at java.util.ResourceBundle.getBundle(ResourceBundle.java:576)
at javax.xml.bind.Messages.format(Messages.java:47)
at javax.xml.bind.Messages.format(Messages.java:36)
at javax.xml.bind.PropertyException.<init>(PropertyException.java:99)
at javax.xml.bind.helpers.AbstractMarshallerImpl.setProperty(AbstractMarshallerImpl.java:349)
at com.sun.xml.internal.bind.v2.runtime.MarshallerImpl.setProperty(MarshallerImpl.java:527)
at Test.main(Test.java:95)
我發現它有做一些與屬性文件：我不使用這樣的事情，我還沒有改變任何東西。
相似主題/可能重複：http://stackoverflow.com/questions/1982977/is-it-possible-to-custo mize-the-namespace-prefix-that-jaxb -chain-marshalling –