RESTeasyJAXB；如何避免将命名空间添加到 any 标记中的元素 （JAXB 中的列表元素）

在使用RESTeasy/JAXB时，有时我们需要将XML数据转换为Java对象，或者将Java对象转换为XML数据。在这个过程中，我们可能会遇到一个问题，即在<any>标记中的元素上添加命名空间。这篇文章将介绍如何避免这个问题，并提供相应的代码示例。

xml
  
    value1
    value2
  

java
@XmlRootElement(name = "root")
public class Root {
  @XmlElement(name = "any")
  private List<Element> elements;
  
  // getter and setter methods
}
@XmlAccessorType(XmlAccessType.FIELD)
public class Element {
  @XmlAnyElement
  private List<Object> anyElement;
  
  // getter and setter methods
}

xml
  
    value1
    value2
  

java
import javax.xml.bind.annotation.adapters.XmlAdapter;
public class AnyElementAdapter extends XmlAdapter<List<ElementWrapper>, List<Element>> {
  @Override
  public List<Element> unmarshal(List<ElementWrapper> wrappers) {
    List<Element> elements = new ArrayList<>();
    for (ElementWrapper wrapper : wrappers) {
      elements.add(wrapper.getElement());
    }
    return elements;
  }
  @Override
  public List<ElementWrapper> marshal(List<Element> elements) {
    List<ElementWrapper> wrappers = new ArrayList<>();
    for (Element element : elements) {
      wrappers.add(new ElementWrapper(element));
    }
    return wrappers;
  }
}

java
@XmlAccessorType(XmlAccessType.FIELD)
public class Element {
  @XmlAnyElement
  @XmlJavaTypeAdapter(AnyElementAdapter.class)
  private List<Element> anyElement;
  
  // getter and setter methods
}

java
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAnyElement;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.adapters.XmlAdapter;
import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
import java.util.ArrayList;
import java.util.List;
@XmlRootElement(name = "root")
public class Root {
  @XmlElement(name = "any")
  private List<Element> elements;
  
  // getter and setter methods
}
@XmlAccessorType(XmlAccessType.FIELD)
public class Element {
  @XmlAnyElement
  @XmlJavaTypeAdapter(AnyElementAdapter.class)
  private List<Element> anyElement;
  
  // getter and setter methods
}
public class ElementWrapper {
  private Element element;
  
  public ElementWrapper() {
  }
  
  public ElementWrapper(Element element) {
    this.element = element;
  }
  
  public Element getElement() {
    return element;
  }
  
  public void setElement(Element element) {
    this.element = element;
  }
}
public class AnyElementAdapter extends XmlAdapter<List<ElementWrapper>, List<Element>> {
  @Override
  public List<Element> unmarshal(List<ElementWrapper> wrappers) {
    List<Element> elements = new ArrayList<>();
    for (ElementWrapper wrapper : wrappers) {
      elements.add(wrapper.getElement());
    }
    return elements;
  }
  @Override
  public List<ElementWrapper> marshal(List<Element> elements) {
    List<ElementWrapper> wrappers = new ArrayList<>();
    for (Element element : elements) {
      wrappers.add(new ElementWrapper(element));
    }
    return wrappers;
  }
}
public class Main {
  public static void main(String[] args) {
    Element element1 = new Element();
    element1.setAnyElement(new ArrayList<>());
    element1.getAnyElement().add(new Element());
    
    Element element2 = new Element();
    element2.setAnyElement(new ArrayList<>());
    element2.getAnyElement().add(new Element());
    element2.getAnyElement().add(new Element());
    
    Root root = new Root();
    root.setElements(new ArrayList<>());
    root.getElements().add(element1);
    root.getElements().add(element2);
    
    // Convert Java object to XML data
    JAXBContext jaxbContext;
    Marshaller marshaller;
    try {
      jaxbContext = JAXBContext.newInstance(Root.class);
      marshaller = jaxbContext.createMarshaller();
      marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
      marshaller.marshal(root, System.out);
    } catch (JAXBException e) {
      e.printStackTrace();
    }
  }
}

xml