Question

我创建了包含以下侦听器方法的Jaxb类，但只有unmarshall方法正在运行：

void afterUnmarshal(Unmarshaller unmarshaller, Object parent) {
        System.out.println("afterUnmarshal  1");
    }

    void beforeMarshal(Marshaller marshaller, Object parent) {
        System.out.println("beforeMarshal  2");
    }

    void beforeUnmarshal(Unmarshaller unmarshaller, Object parent) {
        System.out.println("beforeUnmarshal  3");
    }

    void afterMarshal(Marshaller marshaller, Object parent) {
        System.out.println("afterMarshal  4");
    }

OutPut：

beforeUnmarshal  3
afterUnmarshal  1

执行编组代码时不会调用marshall方法。

更新了问题：问题： beforeMarshal Customer调用了两次。 OutPut：

afterUnmarshal  Address
afterUnmarshal  Customer
beforeMarshal  Customer
beforeMarshal  Customer
beforeMarshal  Address

计划：

 public class Demo {

        public static void main(String[] args) throws Exception {
            JAXBContext jc = JAXBContext.newInstance(Customer.class,ObjectFactory.class);

            Unmarshaller u = jc.createUnmarshaller();
            File xml = new File("src/testRJE/input.xml");
            Customer customer = (Customer) u.unmarshal(xml);

            Marshaller m = jc.createMarshaller();
            m.marshal(customer, xml);
        }

    }


    @XmlRootElement
    @XmlAccessorType(XmlAccessType.FIELD)
    public class Customer {

      @XmlElementRef(name = "billing-address")
      @XmlJavaTypeAdapter(AddressAdapter.class)
      private Address address;

        public Address getAddress() {
            return address;
        }


        void afterUnmarshal(Unmarshaller unmarshaller, Object parent) {//XML to Object
        System.out.println("afterUnmarshal  Customer");
    }

    void beforeMarshal(Marshaller marshaller ) {
        System.out.println("beforeMarshal  Customer");
    }

    }

    @XmlAccessorType(XmlAccessType.FIELD)
    public class Address {

        public Address() {
        }


        private String street;

        private String city;

      void afterUnmarshal(Unmarshaller unmarshaller, Object parent) {
        System.out.println("afterUnmarshal  Address");
    }

    void beforeMarshal(Marshaller marshaller ) {
        System.out.println("beforeMarshal  Address");
    }


    }

Answer 1

marshal事件方法不像unmarshal方法那样有Object参数。当您从方法签名中删除它们时，一切都应该按预期工作。

http://docs.oracle.com/javase/6/docs/api/javax/xml/bind/Marshaller.html#marshalEventCallback

Answer 2

显然，您已经扩展了只有方法afterUnmarshal和beforeUnmarshal的类Unmarshaller#Listener，这解释了为什么只调用这两个方法。

为了收听编组事件，你需要另一个监听器类扩展Marshaller#Listener，而这个类又有你需要的方法和你必须覆盖的方法。

另外，请注释使用注释@Override覆盖的方法。在课堂上完成此操作后，您应该会收到错误消息，指出课程Unmarshaller#Listener没有任何方法beforeMarshal或afterMarshal。

Jaxb API侦听器

2 个答案: