JaxB继承编组抽象类 [英] JaxB inheritance marshalling abstract classes

问题描述

我一直在寻找使用JaxB执行以下操作的最佳方法，但我找不到一种有效的方法。我按照教程这里进行编组并且解组子类。

I've been searching for the best way to perform the following action using JaxB but I cannot find a way that works. I followed the tutorial here to allow for marshaling and unmarshaling of subclasses.

它实现了我正在寻找的所有东西，除了为了使子类被正确编组和解组，它们必须被包装在一个类中使用特定的 @XmlRootElement 。这不允许你自己将类本身表示为Xml。

It achieves all that I am looking for, except that in order for the subclasses to be properly marshaled and unmarshaled, they must be wrapped in a class with a specific @XmlRootElement. This doesn't allow you to represent the classes themselves as Xml on their own.

我希望有这样的类：

import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;   

@XmlJavaTypeAdapter(ContactMethodAdapter.class) 
public abstract class ContactMethod {   

}

public class Address extends ContactMethod {       

    protected String street;      
    protected String city;   

}

public class PhoneNumber extends ContactMethod {       

    protected String number;   

}

我希望能够执行以下操作：

and I want to be able to perform the following:

输入：

<contact-method>
   <street>Broadway</street>
   <city>Seattle</city>
</contact-method>

主要：

public class Demo {       
   public static void main(String[] args) throws Exception  {         
      ContactMethod meth = (ContactMethod ) unmarshaller.unmarshal(xml);

      if(ContactMethod instanceof Address){
         Address addr = (Address) meth;

         addr.getStreet();

         // etc.
      }

      Address marshalAddr = new Address("Broadway", "Seattle");       

      Marshaller marshaller = jc.createMarshaller();         
      marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);         
      marshaller.marshal((ContactMethod) marshalAddr, System.out);     
   }   
}

输出：

<contact-method>
   <street>Broadway</street>
   <city>Seattle</city>
</contact-method>

有谁知道如何实现这一目标？

does anyone know how this can be accomplished?

推荐答案

我最终使用一个类（AdaptedContactMethod）来为抽象类建模。然后我自己处理marshaling和unmarshalling到不同的子类，而不是通过 @XmlJavaTypeAdapter 。

I ended up using one class (AdaptedContactMethod) to model the abstract class. Then I handled the marshaling and unmarshalling to the different subclasses on my own rather than through an @XmlJavaTypeAdapter.

这个允许您在AdaptedContactMethod实现上放置 @XmlRootElement ，而不必将其包装在列表中。

This allows you to put @XmlRootElement on your AdaptedContactMethod implementation without having to wrap it in a list.

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