如何在JAXB Adapter中使用属性作为键，使用整个元素作为值，将复杂元素解析为Map

import javax.xml.bind.annotation.adapters.XmlAdapter;
import java.util.HashMap;
import java.util.Map;

public class ComplexElementAdapter extends XmlAdapter<MapAdapter, Map<String, ComplexElement>> {

    @Override
    public MapAdapter marshal(Map<String, ComplexElement> map) throws Exception {
        MapAdapter mapAdapter = new MapAdapter();
        mapAdapter.setEntries(map);
        return mapAdapter;
    }

    @Override
    public Map<String, ComplexElement> unmarshal(MapAdapter mapAdapter) throws Exception {
        return mapAdapter.getEntries();
    }
}

import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
import java.util.Map;

@XmlRootElement
public class MapAdapter {

    private Map<String, ComplexElement> entries;

    @XmlElement(name = "entry")
    public Map<String, ComplexElement> getEntries() {
        return entries;
    }

    public void setEntries(Map<String, ComplexElement> entries) {
        this.entries = entries;
    }
}

import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
import java.util.Map;

@XmlRootElement
public class MyRootElement {

    private Map<String, ComplexElement> complexElements;

    @XmlJavaTypeAdapter(ComplexElementAdapter.class)
    public Map<String, ComplexElement> getComplexElements() {
        return complexElements;
    }

    public void setComplexElements(Map<String, ComplexElement> complexElements) {
        this.complexElements = complexElements;
    }
}