JAXB类型问题

Question

我有一个看起来像这样的xsd(片段):

<xs:complexType name="IDType">
  <xs:choice minOccurs="1" maxOccurs="2">
    <xs:element name="FileID"    minOccurs="0" maxOccurs="1" type="an..35" />
    <xs:element name="IDNumber1" minOccurs="0" maxOccurs="1" type="an..35" />
    <xs:element name="Number"    minOccurs="0" maxOccurs="1" type="an..35" />
    <xs:element name="PNumber"   minOccurs="0" maxOccurs="1" type="an..35" />
    <xs:element name="SS"        minOccurs="0" maxOccurs="1" type="an..35" />
    <xs:element name="Player"    minOccurs="0" maxOccurs="1" type="an..35" />
    <xs:element name="Prior"     minOccurs="0" maxOccurs="1" type="an..35" />
    <xs:element name="BIN"       minOccurs="0" maxOccurs="1" type="an..35" />
    <xs:element name="Mutual"    minOccurs="0" maxOccurs="1" type="an..35" />
  </xs:choice>
</xs:complexType>
<xs:simpleType name="an..35">
  <xs:restriction base="an">
    <xs:maxLength value="35" />
  </xs:restriction>
</xs:simpleType>

<xs:simpleType name="an">
   <xs:restriction base="xs:string">
     <xs:pattern value="[ !-~]*" />
   </xs:restriction>
</xs:simpleType>

出于某种原因,这是生成的Java代码:

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "IDType", propOrder = {
    "fileID"
})
public class PatientIDType {
    @XmlElementRefs({
        @XmlElementRef(name = "FileED", namespace = "http://www.surescripts.com/messaging", type = JAXBElement.class),
        @XmlElementRef(name = "IDNumber1", namespace = "http://www.surescripts.com/messaging", type = JAXBElement.class),
        @XmlElementRef(name = "Number", namespace = "http://www.surescripts.com/messaging", type = JAXBElement.class),
        @XmlElementRef(name = "PNumber", namespace = "http://www.surescripts.com/messaging", type = JAXBElement.class),
        @XmlElementRef(name = "SS", namespace = "http://www.surescripts.com/messaging", type = JAXBElement.class),
        @XmlElementRef(name = "Plaer", namespace = "http://www.surescripts.com/messaging", type = JAXBElement.class),
        @XmlElementRef(name = "Prior", namespace = "http://www.surescripts.com/messaging", type = JAXBElement.class),
        @XmlElementRef(name = "BIN", namespace = "http://www.surescripts.com/messaging", type = JAXBElement.class),
        @XmlElementRef(name = "Mutual", namespace = "http://www.surescripts.com/messaging", type = JAXBElement.class)
    })
    protected List<JAXBElement<String>> fileID;
    /**
     * Gets the value of the fileID 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 object.
     * This is why there is not a <CODE>set</CODE> method for the fileID property.
     * 
     * <p>
     * For example, to add a new item, do as follows:
     * <pre>
     *    getFileID().add(newItem);
     * </pre>
     * 
     * 
     * <p>
     * Objects of the following type(s) are allowed in the list
     * {@link JAXBElement }{@code <}{@link String }{@code >}
     * {@link JAXBElement }{@code <}{@link String }{@code >}
     * {@link JAXBElement }{@code <}{@link String }{@code >}
     * {@link JAXBElement }{@code <}{@link String }{@code >}
     * {@link JAXBElement }{@code <}{@link String }{@code >}
     * {@link JAXBElement }{@code <}{@link String }{@code >}
     * {@link JAXBElement }{@code <}{@link String }{@code >}
     * {@link JAXBElement }{@code <}{@link String }{@code >}
     * {@link JAXBElement }{@code <}{@link String }{@code >}
     */
    public List<JAXBElement<String>> getFileID() {
        if (fileID == null) {
            fileID = new ArrayList<JAXBElement<String>>();
        }
        return this.fileID;
    }

为什么类生成这样而根本不是某种字符串数组？我真的不想每次想要创建东西时都要创建JAXBElements吗？

我怎样才能为每个只表示字符串或类似字符的类型生成类？

提前致谢,

伊恩

Answer 1

生成此代码是因为您的复杂类型IDType包含maxOccurrence大于1的选项,此处:

<xs:choice minOccurs ="1"maxOccurs ="2">

此列表的内容是具有不同名称但类型相同的元素.这在标准的面向对象模型中没有等价物.然后JAXB使用JAXBElement该类来解决这个问题:a JAXBElement包装一个包含数据的简单对象并为其分配一个QName.

因此,您可以从此列表中读取并通过提供以下内容明确地写入列表:

• 数据对象(在您的情况下为String,因为String的所有限制都表示为Java String)
• 一JAXBElement,其getValue()方法返回字符串

JAXB规范包含了如何处理重复选择和重复序列的相当详细和相当复杂的解释.请注意,如果序列包含不同类型的对象以及不同的名称,则最终将使用List <Object>.

这是一个很长的解释,现在这里有一些选择:

• 如果您可以修改架构,请在8个项目周围放置一个包装元素,例如"Wrapper".包装器将包含单个元素的选择; 然后使IDType包含一系列Wrapper元素,其中minOccurs = 1且maxOccurs = 2.
• 创建一些帮助函数来快速创建JAXBElements.JAXB在您的目标包中放置了一个可以帮助您的Factory类 - 例如,它包含对Schema命名空间的引用等.