java - JAXB 将 1 个 XML 标记映射到 2 个变量

Question

我正在尝试使用一个类来映射我从 XML 请求中获得的响应。但 xml 响应不同，具体取决于自己的一些设置。例如，在响应中我得到标签“所有者”，其中填充了所有者对象的 ID。如果我在我的请求中添加设置，我将取回完整的所有者数据，例如名字和姓氏。现在我想根据响应将所有者标记映射到字符串变量或类。

示例:

@XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement(name = "domain")
public class Response {

    @XmlElement
    private String name;

    @XmlElement(name = "owner")
    private String ownerSimple;

    @XmlElement(name = "owner")
    private Owner ownerComplex;

}

@XmlRootElement(name = "ownerc")
public class OwnerC {

    @XmlElement
    int id;

    @XmlElement
    String fname;

    @XmlElement
    String lname;
}

要映射的 XML:

<response>
    <name>Foo</name>
    <owner>1234</owner>  <!-- in this case it's only a id -->
</response>

<response>
    <name>Foo</name>
    <owner>  <!-- in this case it's the owner class -->
        <id>1234</id>
        <fname>Jon</fname>
        <lname>Doe</lname>
    </owner>
</response>

Answer 1

您可以使用 @XmlAnyElement(lax=true) 来处理这个用例。此批注允许您将任何 XML 解码为 Java 对象(DOM Node)。在第二步中，可以将 Node 解码为所需的对象

响应

@XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement(name = "domain")
public class Response {

    @XmlElement
    private String name;

    @XmlAnyElement(lax=true)
    private Object owner;

    private String ownerSimple;

    @XmlTransient
    private Owner ownerComplex; 

所有者

@XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement(name = "owner")
public class Owner {

    @XmlElement
    int id;

    @XmlElement
    String fname;

    @XmlElement
    String lname;

解码器

//Unmarshaller. Step 1 - Decodes Response and set a DOM Node at Owner
//Important. Owner class must not be present in JAXB context, letting next step to decode the object properly. 
//Owner variable at Response class is annotated with @XmlTransient
JAXBContext jaxbContext = JAXBContext.newInstance(Response.class);
Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
Response response = (Response) jaxbUnmarshaller.unmarshal(reader);

//Unmarshaller. Step 2. Convert Node to the suitable Object
//Considering both cases, simple-> String complex -> Owner Object.      
String ownerSimple = ((Node)response.getOwner()).getFirstChild().getNodeValue();
if (ownerSimple != null){
    response.setOwnerSimple(ownerSimple);
} else {
    JAXBContext jaxbContextOwner = JAXBContext.newInstance(Owner.class);
    Unmarshaller  jaxbUnmarshallerOwner = jaxbContextOwner.createUnmarshaller();
    Owner ownerComplex = (Owner) jaxbUnmarshallerOwner.unmarshal((Node)response.getOwner());
    response.setOwnerComplex(ownerComplex);
}

 //Marshaller to system.out. Your object is well mapped in both cases
 Marshaller marshaller = jaxbContext.createMarshaller();
 marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
 marshaller.marshal(rx, System.out);