JAXB解组问题

Question

我想在下面的线程运行相同的例子：

JAXB Annotations - Mapping interfaces and @XmlElementWrapper

，但我收到以下异常：

意想不到的元素（URI： “”，当地：“狗”）。预计元素< {奇怪的问号}>包罗万象>

...

任何想法，为什么我得到这个例外？

Answer 1

我设法运行的例子，但使用XmlElements标签与java.uill.List 这里之后是代码：

@XmlRootElement class Zoo {

@XmlElements({ 
     @XmlElement(name = "Dog" , type = Dog.class), 
     @XmlElement(name = "Cat" , type = Cat.class) 
}) 
private List<Animal> animals; 

public static void main(String[] args) throws Exception { 
    Zoo zoo = new Zoo(); 
    zoo.animals = new ArrayList<Animal>(); 

    Dog doggy = new Dog(); 
    doggy.setDogProp("Doggy"); 

    Cat catty = new Cat(); 
    catty.setCatProp("Catty"); 

    zoo.animals.add(doggy); 
    zoo.animals.add(catty); 

    JAXBContext jc = JAXBContext.newInstance(Zoo.class, Dog.class, Cat.class); 
    Marshaller marshaller = jc.createMarshaller(); 

    ByteArrayOutputStream os = new ByteArrayOutputStream(); 
    marshaller.marshal(zoo, os); 

    System.out.println(os.toString()); 

    Unmarshaller unmarshaller = jc.createUnmarshaller(); 

    unmarshaller.setEventHandler(new javax.xml.bind.helpers.DefaultValidationEventHandler()); 

    Zoo unmarshalledZoo = (Zoo) unmarshaller.unmarshal(new ByteArrayInputStream(os.toByteArray())); 

    if (unmarshalledZoo.animals == null) { 
     System.out.println("animals was null"); 
    } else if (unmarshalledZoo.animals.size() == 2) { 
     System.out.println("it worked"); 
    } else { 
     System.out.println("failed!"); 
    } 
} 

public interface Animal { 
} 

@XmlRootElement 
public static class Dog implements Animal { 

    private String dogProp; 

    public String getDogProp() { 
     return dogProp; 
    } 

    public void setDogProp(String dogProp) { 
     this.dogProp = dogProp; 
    } 
} 

@XmlRootElement 
public static class Cat implements Animal { 

    private String catProp; 

    public String getCatProp() { 
     return catProp; 
    } 

    public void setCatProp(String catProp) { 
     this.catProp = catProp; 
    } 
} 

}