Question

我正在使用xjc从XML模式生成Java对象。我想使用IDREF在文档中多次引用相同的元素。我还想将IDREF引用的对象约束为特定类型。我想为了模式验证的目的这样做，但是为了在Java代码中，引用的对象作为特定类型而不是Object类型返回。例如，假设我想要一个模式来描述以下内容：

<teams>
  <team id="team1">
    <coach>coachz</coach>
    <player>homestar</player>
    <player>marzipan</player>
    <player>strongsad</player>
    <player>strongbad</player>
  </team>

  <team id="team2">
    <coach>bubs</coach>
    <player>homesar</player>
    <player>thecheat</player>
    <player>poopsmith</player>
    <player>bubs</player>
  </team>

  <team id="allstars">
    <coach>poopsmith</coach>
    <player>coachz</player>
    <player>bubs</player>
    <player>kingoftown</player>
    <player>strongbad</player>
  </team>
</teams>

<people>
 <person id="coachz">Coach Z</person>
 <person id="homesar">Homesar</person>
 <person id="homestar">Homestar</person>
 <person id="strongbad">Strong Bad</person>
 <person id="strongsad">Strong Sad</person>
 <person id="marzipan">Marzipan</person>
 <person id="bubs">Bubs</person>
 <person id="kingoftown">King of Town</person>
 <person id="poopsmith">The Poopsmith</person>
 <person id="thecheat">The Cheat</person>
</people>

我可以像这样定义player：

<xs:element name="player" type="xs:IDREF" maxOccurs="unbounded"/>

但是在Java代码中，当我尝试检索一个播放器时，它将作为类型对象返回，我必须将其转换为一个人。此时，如果有人错误地引用了Team对象，那么我可能会在验证时遇到错误。我想指定这样的东西：

<xs:element name="player" type="xs:IDREF"的 reftype="person" maxOccurs="unbounded" />

但据我所知，没有办法像我在这里用设计属性'reftype'来指定一个类型。可以使用IDREF完成吗？如果没有，还有另一种方法吗？

Answer 1

您只需将baseType绑定应用于player元素即可。类似的东西：

<jaxb:bindings node="xsd:element[@name='player']">
    <jaxb:property>
        <jaxb:baseType name="....Person"/>
    </jaxb:property>
</jaxb:bindings>

您可能需要找出架构的正确绑定位置。

我的代码示例：

架构：

<xsd:complexType name="HJIII-53-A">
    <xsd:sequence>
        <xsd:element name="b" type="xsd:IDREF"/>
        <xsd:element name="b1" type="test:HJIII-53-B"/>
        <xsd:element name="c" type="xsd:IDREFS"/>
        <xsd:element name="c1" type="test:HJIII-53-C" minOccurs="0" maxOccurs="unbounded"/>
    </xsd:sequence>
</xsd:complexType>

绑定：

<jaxb:bindings schemaLocation="schema.xsd" node="/xsd:schema">
    <jaxb:globalBindings localScoping="toplevel">
        <jaxb:serializable/>
    </jaxb:globalBindings>
    <jaxb:bindings node="xsd:complexType[@name='HJIII-53-A']//xsd:element[@name='b']">
        <jaxb:property>
            <jaxb:baseType name="org.jvnet.hyperjaxb3.ejb.tests.issuesjpa2.HJIII53B"/>
        </jaxb:property>
    </jaxb:bindings>
    <jaxb:bindings node="xsd:complexType[@name='HJIII-53-A']//xsd:element[@name='c']">
        <jaxb:property>
            <jaxb:baseType name="org.jvnet.hyperjaxb3.ejb.tests.issuesjpa2.HJIII53C"/>
        </jaxb:property>
    </jaxb:bindings>
</jaxb:bindings>

生成的代码：

@XmlElement(required = true, type = Object.class)
@XmlIDREF
@XmlSchemaType(name = "IDREF")
protected org.jvnet.hyperjaxb3.ejb.tests.issuesjpa2.HJIII53B b;
@XmlElement(required = true)
protected org.jvnet.hyperjaxb3.ejb.tests.issuesjpa2.HJIII53B b1;
@XmlList
@XmlElement(required = true, type = Object.class)
@XmlIDREF
protected List<org.jvnet.hyperjaxb3.ejb.tests.issuesjpa2.HJIII53C> c;
protected List<org.jvnet.hyperjaxb3.ejb.tests.issuesjpa2.HJIII53C> c1;

请参阅：https://svn.java.net/svn/hj3~svn/trunk/ejb/tests/issues-jpa2/src/main/resources/

Answer 2

lexicore的答案给了我我需要的东西（我建议将他的答案投票给我）。但是，我使用内联注释而不是单独的绑定文件。使用我的Homestar示例，这就是内联注释的样子：

<xs:element name="player" type="xs:IDREF" maxoccurs="unbounded">
  <xs:annotation>
    <xs:appinfo>
      <jaxb:property>
        <jaxb:baseType name="Person"/>
      </jaxb:property>
    </xs:appinfo>
  </xs:annotation>
</xs:element>

在XML模式中指定IDREF的类型

2 个答案: