MOXy反序列化异常：在项目中找不到具有默认根元素的描述符

Here are my classes:

这是我的课程：

@XmlRootElement(name="Zoo")
class Zoo {
    //@XmlElementRef
    public Collection<? extends Animal> animals;
}

@XmlAccessorType(XmlAccessType.FIELD)
@XmlSeeAlso({Bird.class, Cat.class, Dog.class})
@XmlDiscriminatorNode("@type")
abstract class Animal {
    @XmlElement
    public String name; 
}

@XmlDiscriminatorValue("Bird")
@XmlRootElement(name="Bird")
class Bird extends Animal {
    @XmlElement
    public String wingSpan;
    @XmlElement
    public String preferredFood;
}

@XmlDiscriminatorValue("Cat")
@XmlRootElement(name="Cat")
class Cat extends Animal {
    @XmlElement
    public String favoriteToy;
}

@XmlDiscriminatorValue("Dog")
@XmlRootElement(name="Dog")
class Dog extends Animal {
    @XmlElement
    public String breed;
    @XmlElement
    public String leashColor;
}
@XmlRootElemen