从XmlStreamReader解组JAXB会导致空对象
[英]JAXB unmarshalling from XmlStreamReader results in null object
问题描述
我创建了一个用于解组XML消息的Java过程，其中可以提供“ startTag”以在消息中的特定元素上开始解组。 我使用XMLStreamReader进行了选择。
下面是我遇到的问题的完整可复制复制的演示。 我需要使用“ xml”消息。 不幸的是，它会在结果中产生一个null汽车对象，而“ xmlStripped”消息会产生一个完全未编组的结果。
我将问题隔离到<response>元素中的xmlns="http://www.example.com/type"命名空间。 当我删除它时，“ xml”已正确解组。
我无法控制 XML。 我需要使用'xml'变量。 我对XSD / ObjectFactory 几乎没有控制权，所以我的第一步是在解组过程中寻找解决方案。
如果您知道失败的原因以及解决方案，请告诉我。 谢谢！
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBElement;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Unmarshaller;
import javax.xml.bind.annotation.*;
import javax.xml.namespace.QName;
import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import java.io.Reader;
import java.io.StringReader;
public class XmlStreamReaderUnmarshallingTest {
private static JAXBContext jaxbContext;
static {
try {
jaxbContext = JAXBContext.newInstance(ObjectFactory.class);
} catch (JAXBException e) {
e.printStackTrace();
}
}
private static String xml = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n" +
"<soapenv:Envelope xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" \n" +
"\txmlns:soapenv=\"http://schemas.xmlsoap.org/soap/envelope/\" \n" +
"\txmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\">\n" +
"\t<soapenv:Body>\n" +
"\t\t<response xmlns=\"http://www.example.com/type\">\n" +
"\t\t\t<type:serviceResponse xmlns:type=\"http://www.example.com/type\">\n" +
"\t\t\t\t<Body>\n" +
"\t\t\t\t\t<Car>\n" +
"\t\t\t\t\t\t<Brand>Mitsubishi</Brand>\n" +
"\t\t\t\t\t\t<Color>Red</Color>\n" +
"\t\t\t\t\t</Car>\n" +
"\t\t\t\t</Body>\n" +
"\t\t\t</type:serviceResponse>\n" +
"\t\t</response>\n" +
"\t</soapenv:Body>\n" +
"</soapenv:Envelope>";
private static String xmlStripped = "<type:serviceResponse xmlns:type=\"http://www.example.com/type\">\n" +
"\t\t\t\t<Body>\n" +
"\t\t\t\t\t<Car>\n" +
"\t\t\t\t\t\t<Brand>Mitsubishi</Brand>\n" +
"\t\t\t\t\t\t<Color>Red</Color>\n" +
"\t\t\t\t\t</Car>\n" +
"\t\t\t\t</Body>\n" +
"\t\t\t</type:serviceResponse>";
public static void main(String[] args) throws JAXBException, XMLStreamException {
readXml(xml, "serviceResponse");
readXml(xmlStripped, "serviceResponse");
}
private static void readXml(String inputXml, String startFromElement) throws JAXBException, XMLStreamException {
final XMLInputFactory xmlInputFactory = XMLInputFactory.newFactory();
final Reader reader = new StringReader(inputXml);
final XMLStreamReader xmlStreamReader = xmlInputFactory.createXMLStreamReader(reader);
final XMLStreamReader streamReader = skipToElement(xmlStreamReader, startFromElement);
final MyServiceResponse serviceResponse = (MyServiceResponse) unmarshal(streamReader);
if(serviceResponse.getBody().getCar() == null) {
System.out.println("It didn't work :-(");
} else {
System.out.println("It worked");
}
}
private static XMLStreamReader skipToElement(final XMLStreamReader xsr, final String startAtElement) throws XMLStreamException {
while (startAtElement != null && xsr.hasNext()) {
xsr.next();
if (xsr.hasName()) {
final String name = xsr.getName().getLocalPart();
if (name.equals(startAtElement)) {
return xsr;
}
}
}
throw new IllegalArgumentException(String.format("Could not find element %s in response", startAtElement));
}
private static Object unmarshal(final XMLStreamReader xsr) throws JAXBException {
final Object entity = unmarshaller(jaxbContext).unmarshal(xsr);
return (entity instanceof JAXBElement ? ((JAXBElement) entity).getValue() : entity);
}
// Create unmarshaller every time
private static Unmarshaller unmarshaller(JAXBContext context) throws JAXBException {
return context.createUnmarshaller();
}
}
@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "MyServiceResponse", propOrder = {
})
class MyServiceResponse {
@XmlElement(name = "Body")
protected MyServiceResponse.Body body;
/**
* Gets the value of the body property.
*
* @return
* possible object is
* {@link MyServiceResponse.Body }
*
*/
public MyServiceResponse.Body getBody() {
return body;
}
/**
* Sets the value of the body property.
*
* @param value
* allowed object is
* {@link MyServiceResponse.Body }
*
*/
public void setBody(MyServiceResponse.Body value) {
this.body = value;
}
/**
* <p>Java class for anonymous complex type.
*
* <p>The following schema fragment specifies the expected content contained within this class.
*
* <pre>
* <complexType>
* <complexContent>
* <restriction base="{http://www.w3.org/2001/XMLSchema}anyType">
* <all>
* <element name="Car" minOccurs="0">
* <complexType>
* <complexContent>
* <restriction base="{http://www.w3.org/2001/XMLSchema}anyType">
* <all>
* <element name="Brand" type="{http://www.w3.org/2001/XMLSchema}string" minOccurs="0"/>
* <element name="Color" type="{http://www.w3.org/2001/XMLSchema}string" minOccurs="0"/>
* </all>
* </restriction>
* </complexContent>
* </complexType>
* </element>
* </all>
* </restriction>
* </complexContent>
* </complexType>
* </pre>
*
*
*/
@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "", propOrder = {
})
public static class Body {
@XmlElement(name = "Car")
protected MyServiceResponse.Body.Car car;
/**
* Gets the value of the car property.
*
* @return
* possible object is
* {@link MyServiceResponse.Body.Car }
*
*/
public MyServiceResponse.Body.Car getCar() {
return car;
}
/**
* Sets the value of the car property.
*
* @param value
* allowed object is
* {@link MyServiceResponse.Body.Car }
*
*/
public void setCar(MyServiceResponse.Body.Car value) {
this.car = value;
}
/**
* <p>Java class for anonymous complex type.
*
* <p>The following schema fragment specifies the expected content contained within this class.
*
* <pre>
* <complexType>
* <complexContent>
* <restriction base="{http://www.w3.org/2001/XMLSchema}anyType">
* <all>
* <element name="Brand" type="{http://www.w3.org/2001/XMLSchema}string" minOccurs="0"/>
* <element name="Color" type="{http://www.w3.org/2001/XMLSchema}string" minOccurs="0"/>
* </all>
* </restriction>
* </complexContent>
* </complexType>
* </pre>
*
*
*/
@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "", propOrder = {
})
public static class Car {
@XmlElement(name = "Brand")
protected String brand;
@XmlElement(name = "Color")
protected String color;
/**
* Gets the value of the brand property.
*
* @return
* possible object is
* {@link String }
*
*/
public String getBrand() {
return brand;
}
/**
* Sets the value of the brand property.
*
* @param value
* allowed object is
* {@link String }
*
*/
public void setBrand(String value) {
this.brand = value;
}
/**
* Gets the value of the color property.
*
* @return
* possible object is
* {@link String }
*
*/
public String getColor() {
return color;
}
/**
* Sets the value of the color property.
*
* @param value
* allowed object is
* {@link String }
*
*/
public void setColor(String value) {
this.color = value;
}
}
}
}
@XmlRegistry
class ObjectFactory {
private final static QName _ServiceResponse_QNAME = new QName("http://www.example.com/type", "serviceResponse");
/**
* Create a new ObjectFactory that can be used to create new instances of schema derived classes for package: com.example.type
*
*/
public ObjectFactory() {
}
/**
* Create an instance of {@link MyServiceResponse }
*
*/
public MyServiceResponse createMyServiceResponse() {
return new MyServiceResponse();
}
/**
* Create an instance of {@link MyServiceResponse.Body }
*
*/
public MyServiceResponse.Body createMyServiceResponseBody() {
return new MyServiceResponse.Body();
}
/**
* Create an instance of {@link MyServiceResponse.Body.Car }
*
*/
public MyServiceResponse.Body.Car createMyServiceResponseBodyCar() {
return new MyServiceResponse.Body.Car();
}
/**
* Create an instance of {@link JAXBElement }{@code <}{@link MyServiceResponse }{@code >}}
*
*/
@XmlElementDecl(namespace = "http://www.example.com/type", name = "serviceResponse")
public JAXBElement<MyServiceResponse> createServiceResponse(MyServiceResponse value) {
return new JAXBElement<MyServiceResponse>(_ServiceResponse_QNAME, MyServiceResponse.class, null, value);
}
}
2 个解决方案
解决方案1
1 已采纳 2017-03-28 14:56:45
您可以通过创建package-info.java并添加以下内容来为模型设置elementFormDefault =“ qualified” ：
package-info.java
@XmlSchema(namespace="http://www.example.com/type", elementFormDefault=XmlNsForm.QUALIFIED)
package mypkg;
import javax.xml.bind.annotation.*;
这将允许您的常规XML，而不是“剥离的” XML，可以工作。 除了外部包装元素的“剥离”之外，两者之间的区别在于原始XML具有默认名称空间集，而剥离的XML没有。
解决方案2
1 2017-03-28 15:08:05
在@XmlType批注上设置name属性：
@XmlType(name = "Body", propOrder = {
})
public static class Body { ... }
和
@XmlType(name = "Car", propOrder = {
})
public static class Car { ... }
xmlns 属性使 object null 与 JAXB 解组
[英]xmlns attribute makes the object null while unmarshalling with JAXB
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