JAXB：与泛型相关的多态性
我试图用泛型中的JAXB（Jersey内部）来进行多态：
@XmlRootElement
public class Performance<M extends IMeasurement> {
@XmlAnyElement
private List<M> measurement;
}
@XmlJavaTypeAdapter(MeasurementAbstract.Adapter.class)
public interface IMeasurement<D extends Serializable, V extends Number>
extends Serializable {
D getDate();
void setDate(D date);
V getValue();
void setValue(V value);
}
@XmlTransient
@XmlAccessorType(XmlAccessType.FIELD)
@XmlSeeAlso({MeasurementStringDouble.class, MeasurementStringInteger.class})
public abstract class MeasurementAbstract<D extends Serializable, V extends Number> implements IMeasurement<D, V> {
@XmlElement
protected D date;
@XmlElement
protected V value;
static class Adapter extends XmlAdapter<MeasurementAbstract, IMeasurement> {
public IMeasurement unmarshal(MeasurementAbstract m) { return m; }
public MeasurementAbstract marshal(IMeasurement v) { return (MeasurementAbstract) v; }
}
}
@XmlRootElement
public class MeasurementStringDouble extends MeasurementAbstract<String, Double> {}
@XmlRootElement
public class MeasurementStringInteger extends MeasurementAbstract<String, Integer> {}
我有这个错误：
GRAVE：映射到响应的异常：500（内部服务器错误）javax.ws.rs.WebApplicationException：javax.xml.bind.MarshalException - 带有链接的异常：[javax.xml.bind.JAXBException：class org.test.jaxb.MeasurementStringDouble也没有任何超级类别在这方面是已知的。]
我找到了解决这个问题的解决方案：
@XmlRootElement
public class Performance<M extends IMeasurement> {
@XmlElementWrapper(name = "measurementsPerformance")
@XmlElements({
@XmlElement(name = "measurement", type = MeasurementStringDouble.class),
@XmlElement(name = "measurement", type = MeasurementStringInteger.class)})
private List<M> measurement;
}
public interface IMeasurement<D extends Serializable, V extends Number> extends Serializable {
D getDate();
void setDate(D date);
V getValue();
void setValue(V value);
}
@XmlTransient
public abstract class MeasurementAbstract<D extends Serializable, V extends Number> implements IMeasurement<D, V>, Serializable {
protected D date;
protected V value;
}
@XmlRootElement
@XmlAccessorType(XmlAccessType.PROPERTY)
public class MeasurementStringDouble extends MeasurementAbstract<String, Double> {
@XmlElement
@Override
public String getDate() {
return date;
}
@XmlElement
@Override
public Double getValue() {
return value;
}
}
@XmlRootElement
@XmlAccessorType(XmlAccessType.PROPERTY)
public class MeasurementStringInteger extends MeasurementAbstract<String, Integer> {
@XmlElement
@Override
public String getDate() {
return date;
}
@XmlElement
@Override
public Integer getValue() {
return value;
}
}
这个解决方案的缺点是重复子类中的getters / setters。
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