java - JAXB 编码子类继承

Question

我有一个对象(部门)，它将成为根元素。它有一个聚合对象(Employee)，它有两个特化(Manager 和 FactoryWorker)。如果我将 Employee 设置为专用对象之一，则仅编码 Employee 对象属性。我将不胜感激任何提示。

例如

@XmlRootElement(name="department")
class Department {
   public Department() {}
   private Employee employee;
   public void setEmployee(final Employee val) {
       this.employee = val;
   }
}

class Employee {
   private Long id;
   public Employee() {}
   //getters and setters
}

class Manager extends Employee {
   public Manager() {}
   private Integer numberOfProjects;
   //getters and setters
}
class FactoryWorker extends Employee {
   public FactoryWorker() {}
   private Boolean worksNights;
   //getters and setters
}

代码片段仅用于显示编码

Deparment department = new Department();
FactoryWorker factoryWorker = new FactoryWorker();
factoryWorker.setId(999);
factoryWorker.setWorksNights(true);

JAXBContext jaxBContext = JAXBContext.newInstance(Department.class);
Marshaller jaxbMarshaller = jaxBContext.createMarshaller();
jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
jaxbMarshaller.marshal(department, System.out);

JAXB 输出:工厂 worker 的特殊属性不存在。只是父 Employee 中的值。

<department>
   <employee>
      <id>999</id>
    </employee>
</department>

Answer 1

你需要这样做:

@XmlRootElement(name="Department")
class Department {
    public Department() {}
    @XmlElements({
        @XmlElement(name="Manager", type=Manager.class),
        @XmlElement(name="FactoryWorker", type=FactoryWorker.class)
    })
    private Employee employee;
    public void setEmployee(Employee val) {this.employee = val;}
}

将输出:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Department>
    <FactoryWorker>
        <id>999</id>
        <worksNights>true</worksNights>
    </FactoryWorker>
</Department>

演示:http://ideone.com/Gw07mI