JAXB 和枚举实现接口

Question

我是 JAXB 的新手（也是 Whosebug 的新手！），我运行在尝试编组和取消编组包含实现接口的枚举列表的对象时遇到了问题。我看了看 here 并尝试了一个类似的例子：

public class testXML {
    private static interface Animal {
        public String getName();
    }

    @XmlRootElement
    private static class Lion implements Animal {
        @XmlElement
        private String name;
        public Lion() { name = "Lion"; }
        @Override public String getName() {
            return name;
        }
    }

    @XmlRootElement
    private static class Dog implements Animal {
        @XmlElement
        private String name;
        public Dog() { name = "Dog"; }
        @Override public String getName() {
            return name;
        }
    }

    @XmlRootElement
    private static class Zoo {
      @XmlElementRefs({
          @XmlElementRef(name = "lion", type = Lion.class, required = true),
          @XmlElementRef(name = "dog", type = Dog.class, required = true)
      })
      public List<Animal> animals;
      public Zoo(Animal ... animals) {
          this.animals = Arrays.asList(animals);
      }
      public Zoo() {
          animals = null;
      }
      public Animal getAnimal(int i) {
          return animals.get(i);
      }
    }

    public static void main(String[] args) throws JAXBException {
        File file = new File("testXML.xml");
        JAXBContext context = JAXBContext.newInstance(
                Zoo.class,
                Lion.class,
                Dog.class);
        //SerializableParameter<ChannelParamEnum> result = new SerializableParameter(ChannelParamEnum.PARAM_CH_FGAIN, 1.0);
        Zoo result = new Zoo(new Lion(), new Dog());
        Marshaller marshaller = context.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
        marshaller.marshal(result, file);

        Zoo unmar = (Zoo)context.createUnmarshaller().unmarshal(file);
        Animal anim = unmar.getAnimal(0);
        System.out.println(anim);
    }
}

这没有问题。然后我尝试将 Lion 和 Dog 类切换为枚举并尝试了以下操作：

public class testXML {
    private static interface Animal {
        public String getName();
    }

    @XmlRootElement
    private static enum Lion implements Animal {
        SIMBA("Simba"),
        MUFASA("Mufasa"),
        SCAR("Scar");

        private String name;
        Lion(String name) { this.name = name; }
        @Override public String getName() {
            return name;
        }
    }

    @XmlRootElement
    private static enum Dog implements Animal {
        PONGO("Pongo"),
        PEGGY("Peggy");

        private String name;
        Dog(String name) { this.name = name; }
        @Override public String getName() {
            return name;
        }
    }

    @XmlRootElement
    private static class Zoo {
      @XmlElementRefs({
          @XmlElementRef(name = "lion", type = Lion.class),
          @XmlElementRef(name = "dog", type = Dog.class)
      })
      public List<Animal> animals;
      public Zoo(Animal ... animals) {
          this.animals = Arrays.asList(animals);
      }
      public Zoo() {
          animals = null;
      }
      public Animal getAnimal(int i) {
          return animals.get(i);
      }
    }

    public static void main(String[] args) throws JAXBException {
        File file = new File("testXML.xml");
        JAXBContext context = JAXBContext.newInstance(
                Lion.class,
                Dog.class,
                Zoo.class);
        Zoo result = new Zoo(Lion.SIMBA, Lion.SCAR, Dog.PONGO);
        Marshaller marshaller = context.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
        marshaller.marshal(result, file);

        Zoo unmar = (Zoo)context.createUnmarshaller().unmarshal(file);
        Animal anim = unmar.getAnimal(0);
        System.out.println(anim);
    }
}

此代码在 JAXBContext.newInstance 中运行时失败

Exception in thread "main" com.sun.xml.internal.bind.v2.runtime.IllegalAnnotationsException: 1 counts of IllegalAnnotationExceptions
Invalid @XmlElementRef : Type "package.testXML$Lion" or any of its subclasses are not known to this context.

显然这不是我的用例，我必须使用枚举而不是类。我环顾四周，但没有找到答案，因此非常感谢您的帮助。

谢谢！

Answer 1

我终于找到了解决办法。足以改变

  @XmlElementRefs({
      @XmlElementRef(name = "lion", type = Lion.class),
      @XmlElementRef(name = "dog", type = Dog.class)
  })

和

  @XmlElements({
      @XmlElement(name="lion", type=Lion.class),
      @XmlElement(name="dog", type=Dog.class)
  })

无论如何，我仍然觉得我在 JAXB 的利用方面有很多不足。

希望对您有所帮助！

JAXB 和枚举实现接口

JAXB and enum implementing interface

java

jaxb2