如何为 XML 映射中的每个列表值指定不同的名称？

Question

I have the following annotation using javax.xml.bind.annotation.XmlElement:

@XmlElement        
public List<String> getKeywords() {
    return keywords;

}

Which produces the following XML:

<keywords>keyword1</keywords>
<keywords>keyword2</keywords>

But I would like to get the below Output:

<A>keyword1</A>
<B>keyword2</B>

I mean some customized tag names for each list value.

Answer 1

Here is an example of such mapping. Main idea is to set @XmlAnyElement on a list getter and provide some mapping function between keywords and tag names. In this example it is achieved using a map, but implementation could be different depending on your logic.

Please note, that it could be difficult to deserialize resulting XML.

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.xml.bind.JAXBElement;
import javax.xml.bind.annotation.XmlAnyElement;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.namespace.QName;

@XmlRootElement(name = "response")
public class Response {

    private List<String> keywords;

    static Map<String, String> names = new HashMap<>();

    static {
        names.put("keyword1", "A");
        names.put("keyword2", "B");
    }

    private String getElementName(String keyword) {
        return names.get(keyword);
    }

    @XmlAnyElement
    public List<JAXBElement<String>> getKeywords() {
        List<JAXBElement<String>> elements = new ArrayList<>();
        keywords.forEach(keyword -> {
            elements.add(new JAXBElement(
                    new QName(getElementName(keyword)), 
                    String.class, 
                    keyword)
            );
        });
        return elements;
    }

    public void setKeywords(List<String> keywords) {
        this.keywords = keywords;
    }

}