有没有一种方法可以将Class作为参数传递给JAXB XMLAdapter或从另一个类访问Getter方法 [英] Is there a way to pass Class as a Parameter to the JAXB XMLAdapter or access Getter method from another class

问题描述

我正在尝试为我的一个对象创建一个 XMLAdapter 类.我需要从另一个类访问 Getters ，以便可以从该类的Getters中填充某些对象，但我无法这样做.

I am trying to create an XMLAdapter class for one of my objects. I need to access Getters from another class so that some of the objects can be populated from that class's Getters` but I am unable to do so.

基本上，我想在 XMLAdapter 中访问我的 Child 类 Getter 方法.我可以创建 Child 类的对象并进行访问，但是会导致 NULL .最初，我在 Child 和 Parent 类中填充 Objects .我想在 XML适配器中访问相同的值，所以我想知道是否有一种方法可以将类的引用传递给我的 XMLAdapter .

Basically, I would like to access my Child class Getter methods within the XMLAdapter. I can create an Object of the Child class and access but it results in NULL. Initially, I am populating the Objects in the Child and Parent class. I would like to access the same value within XML Adapter so I am wondering if there is a way to pass reference of a class to my XMLAdapter.

我有以下 Parent 类，该类将具有值:

I have the following Parent class which will have the values:

@XmlAccessorType(XmlAccessType.FIELD)
@XmlTransient
@XmlSeeAlso({Child.class})
public class Parent{
    private String eventID;
}

以下是我的 Child 类，将在编组期间使用该类创建 XML :

Following is my Child class which will be used during marshalling to create XML:

@XmlRootElement(name = "child")
@XmlType(name = "child", propOrder = { "name","extension"})
public class Child extends Parent
{
    
    @XmlElement (name = "name") 
    private String name;
    
    @JsonIgnore
    @XmlJavaTypeAdapter (ExtensionAdapter.class)
    @XmlElement (name = "extension") 
    private Extension extension;

}

以下是我的扩展程序类:

Following is my Extension class:

@NoArgsConstructor
@AllArgsConstructor
@XmlAccessorType(XmlAccessType.FIELD)
public class Extension {
    private String eventID;
}

以下是我的 XMLAdapter 类:

public class ExtensionAdapter extends XmlAdapter<Child, Extension> {

    @Override
    public Extension unmarshal(Child valueType) throws Exception {
        System.out.println("UN-MARSHALLING");
        return null;
    }

    @Override
    public Child marshal(Extension boundType) throws Exception {
        System.out.println("MARSHALLING");
        System.out.println(boundType);
        //If I create the New child type then I am unable to access the eventID from its getter as Child class is nulll
        Child be = new Child();
        be.setEventID(boundType.getEventID());
        return be;
    }
}

基本上，我想访问 XMLAdapter 中的 Child glass Getter 方法，以便我可以填充 Extension 类 EventID .我尝试了很多事情，但没有任何效果，所以我在这里发布.

Basically, I would like to access the Child glass Getter methods within the XMLAdapter so that I can populate my Extension class EventID with that. I tried a lot of things but nothing worked so I am posting here.

有没有一种方法可以将我的 Child 类作为参数传递给 XMLAdapter ，以便可以从中访问 Getter 方法?因为如果我创建一个 Child 类的新对象，则其所有 Getter 方法都是空的.但是，从一开始，我就填充了 Parent 和 Child 类中的所有字段(名称和事件ID).我只想使用 XMLAdapter 在 Extension 类 eventID 中填充相同的值.

Is there a way I can pass my Child class as a parameter to XMLAdapter so that I can access the Getter methods from it? Because if I create a new Object of Child class then all of its Getter methods are null. However at the start I am populating all the fields in Parent and Child class (name and eventID). I just want to populate the same value within the Extension class eventID using the XMLAdapter.

我希望我能够解释这个需求.如果您有任何建议或示例代码，那将非常有用.

I hope I was able to explain the need. If you have any suggestions or sample code then it would be really useful.

请注意:我在这里使用了非常简单的代码.我知道可以使用适当的POJO和JAXB注释来实现我想达到的目标，但是我的实际类很复杂，不允许修改它.我所能添加的就是新的注释.因此，我正在尝试使用 XMLAdapter 来实现这一目标.

Please Note: I have used very sample code here. I am aware that whatever I am trying to achieve can be achieved using the proper POJO and JAXB Annotations but my actual class is complex and I am not allowed to modify it. All I can add is the new Annotations. Hence, I am trying to achive this using the XMLAdapter.

推荐答案

我想实现类似的功能，因此无需访问该类就可以做到这一点.发布答案，以便将来对某人有用.

I wanted to achieve something like this so I was able to do that without needing to access the class. Posting the answer so it can be useful to somebody in the future.

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import javax.xml.bind.JAXBElement;
import javax.xml.bind.annotation.XmlAnyElement;
import javax.xml.bind.annotation.adapters.XmlAdapter;
import javax.xml.namespace.QName;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.apache.commons.lang3.NotImplementedException;

import io.openepcis.model.jaxb.MyAdapter.MapWrapper;

public class MyAdapter extends XmlAdapter<MapWrapper, Map<String, Object>> {

    private DocumentBuilder documentBuilder;

    public MyAdapter() throws Exception {
        documentBuilder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
    }

    @Override
    public Map<String, Object> unmarshal(MapWrapper valurType) throws Exception {
        throw new NotImplementedException();
    }

    @SuppressWarnings("unchecked")
    @Override
    public MapWrapper marshal(Map<String, Object> m) throws Exception {
        if (m == null) {
            return null;
        }
        MapWrapper wrapper = new MapWrapper();
        List elements = new ArrayList();
        for (Map.Entry<String, Object> property : m.entrySet()) {
            if (property.getValue() instanceof Map) {
                elements.add(new JAXBElement<MapWrapper>(new QName(getCleanLabel(property.getKey())), MapWrapper.class, marshal((Map) property
                                    .getValue())));

            } else {
                elements.add(new JAXBElement<String>(new QName(getCleanLabel(property.getKey())), String.class, property.getValue().toString()));
            }

        }
        wrapper.elements = elements;
        return wrapper;

    }

    // Return a XML-safe attribute. Might want to add camel case support
    private String getCleanLabel(String attributeLabel) {
        attributeLabel = attributeLabel.replaceAll("[()]", "").replaceAll("[^\\w\\s]", "_").replaceAll(" ", "_");
        return attributeLabel;
    }

    public static class MapWrapper {
        @XmlAnyElement
        List elements;
    }

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