Java 如何在JAXB中使用泛型处理枚举？

JAXB运行时无法为其成员变量定义为的类创建JAXBContext

@XmlElement(name = "EnumeraatioArvo")
  private Enum<?> eenum;

@xmlement（name=“EnumeraatioArvo”）
私有枚举；

如何在JAXB中处理这样的场景？

我同意这样做违背了枚举的目的。如果出于某种原因，您需要执行以下操作：

import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;

@XmlRootElement
public class Root {

    private Enum<?> eenum;

    @XmlJavaTypeAdapter(EnumAdapter.class)
    public Enum<?> getEenum() {
        return eenum;
    } 

    public void setEenum(Enum<?> eenum) {
        this.eenum = eenum;
    }

}

我们需要在eenum属性上使用XmlAdapter。XmlAdapter需要知道对该属性有效的所有可能的枚举类型

import javax.xml.bind.annotation.adapters.XmlAdapter;

public class EnumAdapter extends XmlAdapter<String, Enum> {

    private Class[] enumClasses = {Compass.class, Suit.class};

    @Override
    public Enum unmarshal(String v) throws Exception {
        for(Class enumClass : enumClasses) {
            try {
                return (Enum) Enum.valueOf(enumClass, v);
            } catch(IllegalArgumentException  e) {
            }
        }
        return null;
    }

    @Override
    public String marshal(Enum v) throws Exception {
        return v.toString();
    }

}

---

这难道不是违背了枚举的意义吗？

import javax.xml.bind.annotation.adapters.XmlAdapter;

public class EnumAdapter extends XmlAdapter<String, Enum> {

    private Class[] enumClasses = {Compass.class, Suit.class};

    @Override
    public Enum unmarshal(String v) throws Exception {
        for(Class enumClass : enumClasses) {
            try {
                return (Enum) Enum.valueOf(enumClass, v);
            } catch(IllegalArgumentException  e) {
            }
        }
        return null;
    }

    @Override
    public String marshal(Enum v) throws Exception {
        return v.toString();
    }

}

<?xml version="1.0" encoding="UTF-8"?>
<root>
    <eenum>SPADES</eenum>
</root>

import java.io.File;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;

public class Demo {

    public static void main(String[] args) throws Exception {
        JAXBContext jc = JAXBContext.newInstance(Root.class);

        Unmarshaller unmarshaller = jc.createUnmarshaller();
        File xml = new File("input.xml");
        Root root = (Root) unmarshaller.unmarshal(xml);

        Marshaller marshaller = jc.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        marshaller.marshal(root, System.out);
    }
}