jaxb无法创建抽象类的实例
[英]jaxb unable to create an instance of abstract class
问题描述
@XmlSeeAlso({ Dog.class, Cat.class })
public abstract class Animal {}
@XmlRootElement(name="dog")
public class Dog extends Animal {}
@XmlRootElement(name="cat")
public class Cat extends Animal {}
@WebService(name = "WebServiceDemo", serviceName = "WebServiceDemo")
@SOAPBinding(style = SOAPBinding.Style.DOCUMENT, use = SOAPBinding.Use.LITERAL,
parameterStyle = SOAPBinding.ParameterStyle.WRAPPED)
public class WebServiceDemo {
@WebMethod
public String service(@WebParam(name = "animal") Animal animal) {
System.out.println("animal service calling.....");
return animal;
}
}
Now when i am calling this service method from client with Animal calss as a parameter that time i am getting error- 
现在，当我从客户端调用此服务方法时，将Animal calss作为参数，当时我收到错误 -
Caused by: javax.xml.bind.UnmarshalException: Unable to create an instance of Animal - with linked exception: [java.lang.InstantiationException] at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallingContext.handleEvent(UnmarshallingContext.java:616) at com.sun.xml.bind.v2.runtime.unmarshaller.Loader.reportError(Loader.java:244) at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallingContext.createInstance(UnmarshallingContext.java:583) at com.sun.xml.bind.v2.runtime.unmarshaller.StructureLoader.startElement(StructureLoader.java:181) at com.sun.xml.bind.v2.runtime.unmarshaller.XsiTypeLoader.startElement(XsiTypeLoader.java:73) at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallingContext._startElement(UnmarshallingContext.java:455) at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallingContext.startElement(UnmarshallingContext.java:433) at com.sun.xml.bind.v2.runtime.unmarshaller.InterningXmlVisitor.startElement(InterningXmlVisitor.java:71) at com.sun.xml.bind.v2.runtime.unmarsh
1 个解决方案
解决方案1
3 2013-07-18 05:22:55
Abstract classes cannot be instantiated, that is the basic rule for them in Java. 抽象类无法实例化，这是Java中的基本规则。 From the javadocs : 来自javadocs ：
An abstract class is a class that is declared abstract—it may or may not include abstract methods.
Jaxb internally will try to unmarshall your xml to the java object. Jaxb内部将尝试将您的xml解组为java对象。 But if it is not able to create an object of Animal, how will it work. 但如果它无法创建Animal的对象，它将如何工作。 Hence it throws the exception. 因此它抛出异常。 You need to provide a non-abstract class to JaxB to work. 您需要为JaxB提供非抽象类才能工作。
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