JAXB unmarshalling: Kind-Elemente sind null

Question

Ich versuche, ein XML-Dokument zu entpacken:

<map> 
    <room id="1" name="Stairway" east="2"/> 
    <room id="2" name="Kitchen" north="4" south="3" west="1"> 
     <object name="Hat"/> 
    </room> 
    <room id="3" name="Hallway" east="1" south="4"> 
     <object name="Money"/> 
    </room> 
    <room id="4" name="Bathroom" south="2"/> 
</map> 

Und das XSD-Schema (durch ein Werkzeug generiert):

<xsd:schema attributeFormDefault="unqualified" elementFormDefault="qualified" version="1.0" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> 
    <xsd:element name="map"> 
    <xsd:complexType> 
     <xsd:sequence> 
     <xsd:element minOccurs="1" maxOccurs="unbounded" name="room"> 
      <xsd:complexType> 
      <xsd:sequence> 
       <xsd:element minOccurs="0" maxOccurs="unbounded" name="object"> 
       <xsd:complexType> 
        <xsd:attribute name="name" type="xsd:string" /> 
       </xsd:complexType> 
       </xsd:element> 
      </xsd:sequence> 
      <xsd:attribute name="id" type="xsd:int" /> 
      <xsd:attribute name="name" type="xsd:string" /> 
      <xsd:attribute name="north" type="xsd:int" /> 
      <xsd:attribute name="south" type="xsd:int" /> 
      <xsd:attribute name="west" type="xsd:int" /> 
      <xsd:attribute name="east" type="xsd:int" /> 
      </xsd:complexType> 
     </xsd:element> 
     </xsd:sequence> 
    </xsd:complexType> 
    </xsd:element> 
</xsd:schema> 

Dies sind die wichtigen Klassen-Modell :

Map.java

@XmlAccessorType(XmlAccessType.FIELD) 
@XmlType(name = "", propOrder = {"rooms"}) 
@XmlRootElement(name = "map") 
public class Map { 

    /** 
    * List of rooms contained in this map. 
    */ 
    @XmlElement(required = true) 
    protected List<Room> rooms; 

    /** 
    * Gets the value of the rooms property. 
    * 
    * <p> 
    * This accessor method returns a reference to the live list, 
    * not a snapshot. Therefore any modification you make to the 
    * returned list will be present inside the JAXB objects. 
    * This is why there is not a <CODE>set</CODE> method for the rooms property. 
    * 
    * <p> 
    * For example, to add a new item, do as follows: 
    * <pre> 
    * getRooms().add(newItem); 
    * </pre> 
    * 
    * 
    * <p> 
    * Objects of the following type(s) are allowed in the list 
    * {@link Room } 
    * 
    * 
    */ 
    public List<Room> getRooms() { 
     if (rooms == null) { 
      rooms = new ArrayList<Room>(); 
     } 
     return this.rooms; 
    } 

} 

Room.java

@XmlAccessorType(XmlAccessType.FIELD) 
@XmlType(name = "", propOrder = { 
     "objects" 
}) 
public class Room { 

    @XmlElement(required = true) 
    protected List<Object> objects; 
    @XmlAttribute(name = "id") 
    protected Integer id; 
    @XmlAttribute(name = "name") 
    protected String name; 
    @XmlAttribute(name = "north") 
    protected Integer north; 
    @XmlAttribute(name = "south") 
    protected Integer south; 
    @XmlAttribute(name = "west") 
    protected Integer west; 
    @XmlAttribute(name = "east") 
    protected Integer east; 

    /** 
    * Gets the value of the objects property. 
    * 
    * <p> 
    * This accessor method returns a reference to the live list, 
    * not a snapshot. Therefore any modification you make to the 
    * returned list will be present inside the JAXB objects. 
    * This is why there is not a <CODE>set</CODE> method for the objects property. 
    * 
    * <p> 
    * For example, to add a new item, do as follows: 
    * <pre> 
    * getObjects().add(newItem); 
    * </pre> 
    * 
    * 
    * <p> 
    * Objects of the following type(s) are allowed in the list 
    * {@link Object } 
    * 
    * 
    */ 
    public List<Object> getObjects() { 
     if (objects == null) { 
      objects = new ArrayList<Object>(); 
     } 
     return this.objects; 
    } 

    /** 
    * Ruft den Wert der id-Eigenschaft ab. 
    * 
    * @return 
    *  possible objects is 
    *  {@link Integer } 
    *  
    */ 
    public Integer getId() { 
     return id; 
    } 

    /** 
    * Legt den Wert der id-Eigenschaft fest. 
    * 
    * @param value 
    *  allowed objects is 
    *  {@link Integer } 
    *  
    */ 
    public void setId(Integer value) { 
     this.id = value; 
    } 

    /** 
    * Ruft den Wert der name-Eigenschaft ab. 
    * 
    * @return 
    *  possible objects is 
    *  {@link String } 
    *  
    */ 
    public String getName() { 
     return name; 
    } 

    /** 
    * Legt den Wert der name-Eigenschaft fest. 
    * 
    * @param value 
    *  allowed objects is 
    *  {@link String } 
    *  
    */ 
    public void setName(String value) { 
     this.name = value; 
    } 

    /** 
    * Ruft den Wert der north-Eigenschaft ab. 
    * 
    * @return 
    *  possible objects is 
    *  {@link Integer } 
    *  
    */ 
    public Integer getNorth() { 
     return north; 
    } 

    /** 
    * Legt den Wert der north-Eigenschaft fest. 
    * 
    * @param value 
    *  allowed objects is 
    *  {@link Integer } 
    *  
    */ 
    public void setNorth(Integer value) { 
     this.north = value; 
    } 

    /** 
    * Ruft den Wert der south-Eigenschaft ab. 
    * 
    * @return 
    *  possible objects is 
    *  {@link Integer } 
    *  
    */ 
    public Integer getSouth() { 
     return south; 
    } 

    /** 
    * Legt den Wert der south-Eigenschaft fest. 
    * 
    * @param value 
    *  allowed objects is 
    *  {@link Integer } 
    *  
    */ 
    public void setSouth(Integer value) { 
     this.south = value; 
    } 

    /** 
    * Ruft den Wert der west-Eigenschaft ab. 
    * 
    * @return 
    *  possible objects is 
    *  {@link Integer } 
    *  
    */ 
    public Integer getWest() { 
     return west; 
    } 

    /** 
    * Legt den Wert der west-Eigenschaft fest. 
    * 
    * @param value 
    *  allowed objects is 
    *  {@link Integer } 
    *  
    */ 
    public void setWest(Integer value) { 
     this.west = value; 
    } 

    /** 
    * Ruft den Wert der east-Eigenschaft ab. 
    * 
    * @return 
    *  possible objects is 
    *  {@link Integer } 
    *  
    */ 
    public Integer getEast() { 
     return east; 
    } 

    /** 
    * Legt den Wert der east-Eigenschaft fest. 
    * 
    * @param value 
    *  allowed objects is 
    *  {@link Integer } 
    *  
    */ 
    public void setEast(Integer value) { 
     this.east = value; 
    } 

} 

Jetzt, wenn ich versuche, dass XML entordnen map.rooms immer null ist, sollte die Liste der Zimmer sein.

Irgendeine Idee, was das verursacht und wie man es repariert?

Answer 1

Ich glaube, Sie sollten die Namen in XmlElement

@XmlElement(name = "room", required = true) 
protected List<Room> rooms; 

Entweder entweder liefern, rooms den Namen Ihrer Liste in room statt

@XmlElement(required = true) 
protected List<Room> room;