JAXB：与泛型相关的多态性 [英] JAXB: polymorphism with generics

问题描述

我试图在泛型中使用JAXB（Jersey内部）：
$ b

  @XmlRootElement 
 public class Performance< M extends IMeasurement> {
 
 @XmlAnyElement 
私人列表< M>测量; 
 
  

  @XmlJavaTypeAdapter（MeasurementAbstract.Adapter.class）
 public interface IMeasurement< D extends Serializable，V extends Number> 
扩展了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>实现IMeasurement< D，V> {
 
 @XmlElement 
保护D日期; 
 @XmlElement 
保护V值; 
 
静态类适配器扩展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 
公共类MeasurementStringInteger扩展MeasurementAbstract< String，Integer> {bb} {/ code> 

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 - 具有链接异常的
：[ javax.xml.bind.JAXBException：类
org.test.jaxb.MeasurementStringDouble或其任何超类都是
已知此上下文。]




解决方案

我找到了一个解决方案来解决这个问题：



  @XmlRootElement 
 public class Performance< M extends IMeasurement> （
 @XmlElement（name =measurement，type = MeasurementStringDouble.class），
 @XmlElement（name =measurement，type = MeasurementStringInteger.class）}）
 private List< M>测量; 
 
  





  public interface IMeasurement< D extends Serializable，V extends Number>扩展Serializable {
 
 D getDate（）; 
 void setDate（D date）; 
 V getValue（）; 
 void setValue（V value）; 
 
  





  @XmlTransient 
 public abstract class MeasurementAbstract< D extends Serializable，V extends Number>实现IMeasurement< D，V>，可序列化{
 
保护D日期; 
保护V值; 
 
  





  @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getters / setters在子类中。

I'm trying to use JAXB (inside Jersey) for polymorphism with generics:

@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> {}

I have this error:

GRAVE: Mapped exception to response: 500 (Internal Server Error) javax.ws.rs.WebApplicationException: javax.xml.bind.MarshalException - with linked exception: [javax.xml.bind.JAXBException: class org.test.jaxb.MeasurementStringDouble nor any of its super class is known to this context.]

解决方案

I found a solution to solve this problem:

@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;
    }
}

The drawback of this solution is duplicate the getters/setters in sub-classes.

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