java - 将类编码到 XSD :Anytype xml

Question

我的问题是我有一个 MessageList 类型的类，它包含 Message 项，定义如下:

<xsd:complexType name="MessageType">
    <xsd:sequence>
        <xsd:any/>
    </xsd:sequence>
</xsd:complexType>
<xsd:element name="Message" type="tns:MessageType"/>
<xsd:complexType name="MessageListType">
    <xsd:sequence>
        <xsd:element name="Message" maxOccurs="unbounded"/>
    </xsd:sequence>
</xsd:complexType>
<xsd:element name="MessageList" type="tns:MessageListType"/>

我的消息类看起来像(这里省略了 getter 和 setter)

public class Message
{
private String referenceId;
private String messageType;
private Timestamp createdTime;
private String transactionIdForeignKey;
private String xmlDetail;
}

当我尝试在我的 servlet 中编码此类时:

         List<Message> retrievedMessages = new ArrayList<Message>();
         retrievedMessages.add(new Message);
         retrievedMessages.add(new Message);

         MessageListType messageListType = new MessageListType();
         for(Message message: retrievedMessages){
             messageListType.getMessage().add(message);
         }

我收到以下错误:

[#|2013-04-25T16:43:40.434+0100|WARNING|sun-appserver2.1|javax.enterprise.system.stream.err|_ThreadID=188;_ThreadName=p: thread-pool-1; w: 76;_RequestID=40c6fe10-c12f-4d0b-8912-c960381910d7;|
javax.xml.ws.WebServiceException: javax.xml.bind.MarshalException
 - with linked exception:
[javax.xml.bind.JAXBException: class uk.co.test.test.audit.model.Message nor any of its super class is known to this context.]
    at com.sun.xml.ws.message.jaxb.JAXBMessage.writePayloadTo(JAXBMessage.java:322)
    at com.sun.enterprise.jbi.serviceengine.comm.WrappedMessage.writePayloadTo(WrappedMessage.java:419)
    at com.sun.enterprise.jbi.serviceengine.comm.WrappedMessage$DocumentStyleWrapper.wrap(WrappedMessage.java:215)
    at com.sun.enterprise.jbi.serviceengine.comm.WrappedMessage.wrap(WrappedMessage.java:170)
    at com.sun.enterprise.jbi.serviceengine.comm.ProviderInOut.send(ProviderInOut.java:143)
    at com.sun.enterprise.jbi.serviceengine.bridge.transport.NMRServerConnection.sendResponse(NMRServerConnection.java:81)
    at com.sun.enterprise.jbi.serviceengine.bridge.transport.JBIAdapter$WSToolkit.handle(JBIAdapter.java:127)
    at com.sun.enterprise.jbi.serviceengine.bridge.transport.JBIAdapter.handle(JBIAdapter.java:86)
    at com.sun.enterprise.jbi.serviceengine.bridge.JAXWSMessageProcessor.doWork(JAXWSMessageProcessor.java:93)
    at com.sun.corba.ee.impl.orbutil.threadpool.ThreadPoolImpl$WorkerThread.run(ThreadPoolImpl.java:555)
Caused by: javax.xml.bind.MarshalException
 - with linked exception:
[javax.xml.bind.JAXBException: class uk.co.test.test.audit.model.Message nor any of its super class is known to this context.]
    at com.sun.xml.bind.v2.runtime.MarshallerImpl.write(MarshallerImpl.java:282)
    at com.sun.xml.bind.v2.runtime.BridgeImpl.marshal(BridgeImpl.java:100)
    at com.sun.xml.bind.api.Bridge.marshal(Bridge.java:141)
    at com.sun.xml.ws.message.jaxb.JAXBMessage.writePayloadTo(JAXBMessage.java:315)

有人知道为什么会这样吗？我猜正在执行编码的 servlet 需要知道要查看哪个类，但我不确定该怎么做？

Answer 1

如果您想在类里面如此精确，则需要在 Schema 中更加精确。

JAXB 依赖于定义结构的模式，该结构与您希望 JAXB 解码到的结构相同。

为了说明，让我们使用 xjc 编译您的模式- 这将创建 JAXB 可以自动编码并对其进行注释的类。

这是类:

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

    @XmlAnyElement(lax = true)
    protected Object any;

    public Object getAny() {
        return any;
    }

    public void setAny(Object value) {
        this.any = value;
    }

}

您可以看到，JAXB 只能从您的模式中判断出您有一个 MessageType。包含未知数量的东西的类 - <xsd:any/> - 例如，JAXB 无法确定您有一个 String称为 referenceId需要设置。

如果您可以更改架构，则更新为

<xsd:complexType name="MessageType">
    <xsd:attribute name="referenceId" type="xsd:string"/>
    <xsd:attribute name="messageType" type="xsd:string"/>
    <xsd:attribute name="transactionIdForeignKey" type="xsd:string"/>
    <xsd:attribute name="xmlDetail" type="xsd:string"/>        
    <xsd:attribute name="createdTime" type="xsd:integer"/>        
</xsd:complexType>

告诉 JAXB 构建类所需的信息(在这种情况下，TimeStamp 是 long - 要解码为 TimeStamp，您需要一些 custom logic)。

生成的类现在类似于您自己的类:

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "MessageType")
public class MessageType {

    @XmlAttribute(name = "referenceId")
    protected String referenceId;
    @XmlAttribute(name = "messageType")
    protected String messageType;
    @XmlAttribute(name = "transactionIdForeignKey")
    protected String transactionIdForeignKey;
    @XmlAttribute(name = "xmlDetail")
    protected String xmlDetail;
    @XmlAttribute(name = "createdTime")
    protected BigInteger createdTime;

    public String getReferenceId() {
        return referenceId;
    }

    public void setReferenceId(String value) {
        this.referenceId = value;
    }

    public String getMessageType() {
        return messageType;
    }

    public void setMessageType(String value) {
        this.messageType = value;
    }

    public String getTransactionIdForeignKey() {
        return transactionIdForeignKey;
    }

    public void setTransactionIdForeignKey(String value) {
        this.transactionIdForeignKey = value;
    }

    public String getXmlDetail() {
        return xmlDetail;
    }

    public void setXmlDetail(String value) {
        this.xmlDetail = value;
    }

    public BigInteger getCreatedTime() {
        return createdTime;
    }

    public void setCreatedTime(BigInteger value) {
        this.createdTime = value;
    }

}

可以看到xml中的属性直接映射到类中的字段。您还可以看到 JAXB 使用的注释，这些是 not required但有助于告诉它什么映射到哪里。

如果您无法更改架构，那么您将需要实现自定义逻辑来搜索您的 <xsd:any/>对于相关属性和 map ，然后手动。 This如果你沿着那条路走下去，应该会让你开始。