JAXB/Moxy Unmarshalling 将所有字段值分配给 Map<String,Object>;而不是为其提供的特定字段 [英] JAXB/Moxy Unmarshalling assigns all field values to Map&lt;String,Object&gt; rather than the specific field provided for it

问题描述

简而言之，我想执行解组 正如这里提到的，但与 Map 一起，我还有一个 @XmlElement.所以一个字段用 (Map field) @XmlPath(".") 注释，另一个字段用 (String field) @XmlElement 注释，然后我想执行解组.

In short, I would like to perform the unmarshalling as mentioned here but along with Map I will have one more @XmlElement. So one field is annotated with (Map field) @XmlPath(".") and another field with (String field) @XmlElement and then I would like to perform unmarshalling.

我的应用程序的主要目标是使用 JAXB/Moxy 和 Jackson 转换 XML->JSON 和 JSON->XML> 图书馆.我正在尝试 unmarshal XML 并将其映射到 Java POJO.我的 XML 可以有一些专用元素和一些用户定义的元素，它们可能随机出现，所以我想将它们存储在 Map 中.因此，我正在使用 XMLAdapter.我正在关注 博客文章这样做.我做的不是完全一样，而是有点不同.

My main goal of the application is to convert XML->JSON and JSON->XML using the JAXB/Moxy and Jackson library. I am trying to unmarshal the XML and map it to the Java POJO. My XML can have some dedicated elements and some user-defined elements which can appear random so I would like to store them in Map<String, Object>. Hence, I am making use of XMLAdapter. I am following the blog article to do so. I am not doing exactly the same but a bit different.

我面临的问题是在 unmarshalling 期间根本没有考虑专用字段.所有值都解组到Map.根据我的理解，这是由于注释 @XmlPath(".") 和 XMLAdapter 的使用而发生的，但是如果我删除此注释，它将无法正常工作预期的.有人可以帮我解决这个问题吗?marshaling 适用于 @XmlPath(".") 和 XMLAdapter.问题仅在解组期间出现.

The problem I am facing is during unmarshalling the dedicated fields are not taken into consideration at all. All the values are unmarshalled to Map<String.Object>. As per my understanding it's happening because of the annotation @XmlPath(".") and usage of XMLAdapter but If I remove this annotation then it won't work as expected. Can someone please help me with this issue? The marshaling works fine with both @XmlPath(".") and XMLAdapter. The problem is arising only during unmarshalling.

以下是我想转换为 JSON 的 XML:(注意:Name 和 Age是专用字段，others 是 user-defined 字段.)

Following is my XML that I would like to convert to JSON: (Note: Name and Age are dedicated fields and others is the user-defined field.)

<Customer xmlns:google="https://google.com">
  <name>BATMAN</name>
  <age>2008</age>
  <google:main>
    <google:sub>bye</google:sub>
  </google:main>
</Customer>

以下是我的 Customer 类，用于 marshaling、unmarshalling 由 Moxy 和 Jackson:(注意:Name 和 Age 是专用字段，others 是 user-defined 字段.我希望 others 仅存储不能直接映射到 POJO 的值，例如 google:main 及其上面 XML 的子项)

Following is my Customer class used for marshaling, unmarshalling by Moxy and Jackson: (Note: Name and Age are dedicated fields and others is the user-defined field. I want others to store only the values that cannot be mapped directly to POJO such as google:main and its children from above XML)

@XmlRootElement(name = "Customer")
@XmlType(name = "Customer", propOrder = {"name", "age", "others"})
@XmlAccessorType(XmlAccessType.FIELD)
public class Customer {
  private String name;
  private String age;

  @XmlPath(".")
  @XmlJavaTypeAdapter(TestAdapter.class)
  private Map<String, Object> others;
  //Getter, Setter and other constructors
}

以下是我的 TestAdapter 类，它将用于 Userdefined 字段:

Following is my TestAdapter class which will be used for the Userdefined fields:

class TestAdapter extends XmlAdapter<Wrapper, Map<String, Object>> {

  @Override
  public Map<String, Object> unmarshal(Wrapper value) throws Exception {
    System.out.println("INSIDE UNMARSHALLING METHOD TEST");
    final Map<String, Object> others = new HashMap<>();

    for (Object obj : value.getElements()) {
      final Element element = (Element) obj;
      final NodeList children = element.getChildNodes();

      //Check if its direct String value field or complex
      if (children.getLength() == 1) {
        others.put(element.getNodeName(), element.getTextContent());
      } else {
        List<Object> child = new ArrayList<>();
        for (int i = 0; i < children.getLength(); i++) {
          final Node n = children.item(i);
          if (n.getNodeType() == Node.ELEMENT_NODE) {
            Wrapper wrapper = new Wrapper();
            List childElements = new ArrayList();
            childElements.add(n);
            wrapper.elements = childElements;
            child.add(unmarshal(wrapper));
          }
        }
        others.put(element.getNodeName(), child);
      }
    }

    return others;
  }

  @Override
  public Wrapper marshal(Map<String, Object> v) throws Exception {
    Wrapper wrapper = new Wrapper();
    List elements = new ArrayList();
    for (Map.Entry<String, Object> property : v.entrySet()) {
      if (property.getValue() instanceof Map) {
        elements.add(new JAXBElement<Wrapper>(new QName(property.getKey()), Wrapper.class, marshal((Map) property.getValue())));
      } else {
        elements.add(new JAXBElement<String>(new QName(property.getKey()), String.class, property.getValue().toString()));
      }
    }
    wrapper.elements = elements;
    return wrapper;
  }
}

@Getter
class Wrapper {

  @XmlAnyElement
  List elements;
}

最后，我的 Main 类将用于 marshaling 和 unmarshalling.此外，转换为 JSON 和 XML.

And finally, my Main class will be used for marshaling and unmarshalling. Also, to convert to JSON and XML.

class Main {

  public static void main(String[] args) throws JAXBException, XMLStreamException, JsonProcessingException {

    //XML to JSON
    JAXBContext jaxbContext = JAXBContext.newInstance(Customer.class);
    Unmarshaller unmarshaller = jaxbContext.createUnmarshaller();
    InputStream inputStream = Main.class.getClassLoader().getResourceAsStream("Customer.xml");
    final XMLInputFactory xmlInputFactory = XMLInputFactory.newInstance();
    final XMLStreamReader streamReader = xmlInputFactory.createXMLStreamReader(inputStream);
    final Customer customer = unmarshaller.unmarshal(streamReader, Customer.class).getValue();
    final ObjectMapper objectMapper = new ObjectMapper();
    final String jsonEvent = objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(customer);
    System.out.println(jsonEvent);

    //JSON to XML
    Marshaller marshaller = jaxbContext.createMarshaller();
    marshaller.setProperty(Marshaller.JAXB_FRAGMENT, Boolean.TRUE);
    marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
    marshaller.marshal(customer, System.out);
  }
}

当我转换 XML->JSON 时，我得到以下输出:(如果您观察字段 name 和 age不作为来自 Customer 类的专用字段，而是作为随机字段并写入 others)

When I convert the XML->JSON then I get the following output: (If you observe the fields name and age are not taken as the dedicated fields from Customer class rather its taken as random fields and written within the others)

{
  "name" : "",
  "age" : "",
  "others" : {
    "google:main" : [ {
      "google:sub" : "bye"
    } ],
    "name" : "BATMAN",
    "age" : "2008"
  }
}

我希望我的输出是这样的:(我希望首先映射我的专用字段，然后如果有任何未知字段，则稍后在 others MAP 中映射它们).请注意，我不想在我的 JSON 中获得 others 标签.我只想获取专用字段的字段名称.

I want my output to be something like this: (I want my dedicated fields to be mapped first then if there are any unknown fields then map them later within others MAP). Please note that I do not want to get others tag within my JSON. I want to get the names of the fields only for the dedicated fields.

{
  "name": "BATMAN",
  "age": 2008,
  "google:main": {
    "google:sub": "bye"
  }
}

以下是我希望在 marshaling 期间获得的 XML.另外，请注意我正在使用 @XmlPath(".") 这样我就不会在我的 XML 中获得 others 节点编组.

Following is the XML that I would like to get during the marshaling. Also, please note I am using @XmlPath(".") so that I do not get the others node within my XML during marshaling.

<Customer>
    <name>BATMAN</name>
    <age>2008</age>
    <google:main>>
        <google:sub>bye</google:sub>
    </google:main>
</Customer>

编组 工作正常.问题发生在 .unmarshaling 根据我的理解，这是由于 @XmlPath(".") 和 XMLAdapter 的注释而发生的，但是如果我删除此注释，则它将无法按预期工作.有人可以帮我解决这个问题吗?

The marshaling is working fine. The problem is happening during .unmarshaling As per my understanding it's happening because of the annotation @XmlPath(".") with XMLAdapter but If I remove this annotation then it won't work as expected. Can someone please help me with this issue?

** 已编辑 **

我想到了一些解决方法，但似乎对我不起作用.由于 @XmlPath(".")，它们变得一团糟.仍在寻找一些想法或解决方法.任何帮助将不胜感激.

I thought of a few workarounds but nothing seems to work for me. They are getting messed up due to @XmlPath("."). Still looking for some idea or workarounds. Any help would be really appreciated.

推荐答案

啊，终于松了口气.这个问题让我很头疼，但我终于找到了解决方法.尝试了很多事情并联系了很多人，但似乎没有任何效果，我认为这是 JAXB/Moxy 库的问题.我找到了解决方法.希望它对未来的人有所帮助，不要像我一样感到沮丧:)

ah, finally some relief. This issue ate my head a lot but I was finally able to find a workaround. Tried a lot of things and reached out to many people but nothing seems to work and I thought it's an issue from the JAXB/Moxy library. I was able to find a workaround. Hope it helps someone in the future and do not get frustrated like me :)

我使用了 2 个字段，一个带有 @XmlAnyElement(lax=true) List