如何使用MOXy绑定文件处理java.util.Date

Question

我是MOXy和JaxB的新手，我遇到了java.util.Date转换的问题。

我正在使用映射文件将XML文件（我无法控制）解组为对象（我既不能手动注释现有类也不能更改它们。）

我的XML映射文件如下所示：

<?xml version="1.0"?>
<xml-bindings 
        xmlns="http://www.eclipse.org/eclipselink/xsds/persistence/oxm"
        version="2.1">
    <java-types>
        <java-type name="Observation">
            <xml-type prop-order="date theoricalTime ci ch cr type" />
            <java-attributes>
                <xml-element java-attribute="date" xml-path="Date/text()" />
                <xml-element java-attribute="theoricalTime" xml-path="TheoricalTime/text()" />
                <xml-element java-attribute="ci" xml-path="CIPR/text()" />
                <xml-element java-attribute="ch" xml-path="CHPR/text()" />
                <xml-element java-attribute="cr" xml-path="CRPR/text()" />
                <xml-element java-attribute="type" xml-path="Type/text()" />
            </java-attributes>
        </java-type>
    </java-types>
</xml-bindings>

在我正在编组的类中，属性“date”和“theoricalTime”的类型为java.util.Date。

我正在编组的xml中的值是具有这种格式的字符串：“dd / MM / yyyy HH：mm：ss”（“05/01/2012 16:36:24”）。我也有一些只有时间值“HH：mm：ss”（“14:17:33”）的字段。

这是我在解组文件时得到的堆栈跟踪：

Exception in thread "main" Local Exception Stack: 
Exception [EclipseLink-3002] (Eclipse Persistence Services - 2.3.2.v20111125-r10461): org.eclipse.persistence.exceptions.ConversionException
Exception Description: The object [22/01/2009 20:56:29], of class [class java.lang.String], from mapping [org.eclipse.persistence.oxm.mappings.XMLDirectMapping[date-->Date/text()]] with descriptor [XMLDescriptor(Observation --> [DatabaseTable(Observation)])], could not be converted to [class java.util.Calendar].
    at org.eclipse.persistence.exceptions.ConversionException.incorrectDateTimeFormat(ConversionException.java:127)
    at org.eclipse.persistence.exceptions.ConversionException.incorrectDateTimeFormat(ConversionException.java:133)
    at org.eclipse.persistence.internal.oxm.XMLConversionManager.convertStringToXMLGregorianCalendar(XMLConversionManager.java:703)
    at org.eclipse.persistence.internal.oxm.XMLConversionManager.convertStringToDate(XMLConversionManager.java:1111)
    at org.eclipse.persistence.internal.oxm.XMLConversionManager.convertObjectToUtilDate(XMLConversionManager.java:804)
    at org.eclipse.persistence.internal.oxm.XMLConversionManager.convertObject(XMLConversionManager.java:165)
    at org.eclipse.persistence.internal.databaseaccess.DatasourcePlatform.convertObject(DatasourcePlatform.java:160)
    at org.eclipse.persistence.oxm.mappings.XMLDirectMapping.getAttributeValue(XMLDirectMapping.java:293)
    at org.eclipse.persistence.internal.oxm.XMLDirectMappingNodeValue.endElement(XMLDirectMappingNodeValue.java:182)
    at org.eclipse.persistence.oxm.record.UnmarshalRecord.endElement(UnmarshalRecord.java:823)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.endElement(AbstractSAXParser.java:601)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanEndElement(XMLDocumentFragmentScannerImpl.java:1774)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2930)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:648)
    at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:140)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:510)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:807)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:737)
    at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:107)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1205)
    at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:522)
    at org.eclipse.persistence.internal.oxm.record.XMLReader.parse(XMLReader.java:157)
    at org.eclipse.persistence.internal.oxm.record.SAXUnmarshaller.unmarshal(SAXUnmarshaller.java:753)
    at org.eclipse.persistence.internal.oxm.record.SAXUnmarshaller.unmarshal(SAXUnmarshaller.java:333)
    at org.eclipse.persistence.internal.oxm.record.SAXUnmarshaller.unmarshal(SAXUnmarshaller.java:320)
    at org.eclipse.persistence.internal.oxm.record.SAXUnmarshaller.unmarshal(SAXUnmarshaller.java:280)
    at org.eclipse.persistence.oxm.XMLUnmarshaller.unmarshal(XMLUnmarshaller.java:306)
    at org.eclipse.persistence.jaxb.JAXBUnmarshaller.unmarshal(JAXBUnmarshaller.java:115)
    at Main.Test(Main.java:97)
    at Main.main(Main.java:35)

我的问题是：是否可以使用MOXy的外部元数据在映射文件中指定类型转换？如何使用上面指定的格式处理日期时间并将它们映射到日期字段？

（我暗暗希望Blaise Doughan正在读这篇文章。）

提前感谢您的帮助！

Answer 1

以下内容演示了如何使用XmlAdapter和MOXy的外部映射文档来实现您正在寻找的结果：

<强> DateAdapter

由于您的日期/时间数据采用以下格式dd/MM/yyyy HH:mm:ss，因此您需要使用XmlAdapter，如下所示：

package forum8745305;

import java.text.SimpleDateFormat;
import java.util.Date;

import javax.xml.bind.annotation.adapters.XmlAdapter;

public class DateAdapter extends XmlAdapter<String, Date> {

    private SimpleDateFormat dateFormat = new SimpleDateFormat("dd/MM/yyyy HH:mm:ss");

    @Override
    public String marshal(Date v) throws Exception {
        return dateFormat.format(v);
    }

    @Override
    public Date unmarshal(String v) throws Exception {
        return dateFormat.parse(v);
    }

}

<强> oxm.xml

这通常使用@XmlJavaTypeAdapter注释在您的域模型中指定，但由于您使用的是MOXy的外部元数据文档，因此您可以按如下方式指定它。我已在包级别指定它，以便它将应用于属于该包中的域类的java.util.Date类型的所有字段/属性：

<?xml version="1.0"?>
<xml-bindings 
        xmlns="http://www.eclipse.org/eclipselink/xsds/persistence/oxm"
        version="2.1"
        package-name="forum8745305">
    <xml-java-type-adapters>
        <xml-java-type-adapter value="forum8745305.DateAdapter" type="java.util.Date"/>
    </xml-java-type-adapters>
    <java-types>
        <java-type name="Observation">
            <xml-type prop-order="date theoricalTime ci ch cr type" />
            <xml-root-element/>
            <java-attributes>
                <xml-element java-attribute="date" xml-path="Date/text()"/>
                <xml-element java-attribute="theoricalTime" xml-path="TheoricalTime/text()" />
                <xml-element java-attribute="numeroTrain" xml-path="NumeroTrain/text()" />
                <xml-element java-attribute="ci" xml-path="CIPR/text()" />
                <xml-element java-attribute="ch" xml-path="CHPR/text()" />
                <xml-element java-attribute="cr" xml-path="CRPR/text()" />
                <xml-element java-attribute="type" xml-path="Type/text()" />
            </java-attributes>
        </java-type>
    </java-types>
</xml-bindings>

<强>观察

根据您的问题，以下是您的域类的外观：

package forum8745305;

import java.util.Date;

public class Observation {

    private Date date;
    private Date theoricalTime;
    private String numeroTrain;
    private String ci;
    private String ch;
    private String cr;
    private String type;

    public Date getDate() {
        return date;
    }

    public void setDate(Date date) {
        this.date = date;
    }

    public Date getTheoricalTime() {
        return theoricalTime;
    }

    public void setTheoricalTime(Date theoricalTime) {
        this.theoricalTime = theoricalTime;
    }

    public String getNumeroTrain() {
        return numeroTrain;
    }

    public void setNumeroTrain(String numeroTrain) {
        this.numeroTrain = numeroTrain;
    }

    public String getCi() {
        return ci;
    }

    public void setCi(String ci) {
        this.ci = ci;
    }

    public String getCh() {
        return ch;
    }

    public void setCh(String ch) {
        this.ch = ch;
    }

    public String getCr() {
        return cr;
    }

    public void setCr(String cr) {
        this.cr = cr;
    }

    public String getType() {
        return type;
    }

    public void setType(String type) {
        this.type = type;
    }

}

<强>演示

以下代码可用于运行示例：

package forum8745305;

import java.io.File;
import java.util.HashMap;
import java.util.Map;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;

import org.eclipse.persistence.jaxb.JAXBContextFactory;

public class Demo {

    public static void main(String[] args) throws Exception {
        Map<String, Object> properties = new HashMap<String, Object>(1);
        properties.put(JAXBContextFactory.ECLIPSELINK_OXM_XML_KEY, "forum8745305/oxm.xml");
        JAXBContext jc = JAXBContext.newInstance(new Class[] {Observation.class}, properties);

        Unmarshaller unmarshaller = jc.createUnmarshaller();
        File xml = new File("src/forum8745305/input.xml");
        Observation observation = (Observation) unmarshaller.unmarshal(xml);

        Marshaller marshaller = jc.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        marshaller.marshal(observation, System.out);
    }

}

<强>输入/输出

<?xml version="1.0" encoding="UTF-8"?>
<observation>
    <Date>05/01/2012 16:36:24</Date>
    <TheoricalTime>01/02/2012 12:34:45</TheoricalTime>
</observation>

了解更多信息

• http://blog.bdoughan.com/2011/05/specifying-eclipselink-moxy-as-your.html
• http://blog.bdoughan.com/2010/12/extending-jaxb-representing-annotations.html
• http://blog.bdoughan.com/search/label/XmlAdapter

<强>更新

您还可以在属性级别指定XmlAdapters。这意味着，如果您愿意，可以为每个XmlAdapter属性设置不同的Date。

<?xml version="1.0"?>
<xml-bindings 
        xmlns="http://www.eclipse.org/eclipselink/xsds/persistence/oxm"
        version="2.1"
        package-name="forum8745305">
    <java-types>
        <java-type name="Observation">
            <xml-type prop-order="date theoricalTime ci ch cr type" />
            <xml-root-element/>
            <java-attributes>
                <xml-element java-attribute="date" xml-path="Date/text()">
                    <xml-java-type-adapter value="forum8745305.DateAdapter"/>
                </xml-element>
                <xml-element java-attribute="theoricalTime" xml-path="TheoricalTime/text()">
                    <xml-java-type-adapter value="forum8745305.DateAdapter"/>
                </xml-element>
                <xml-element java-attribute="numeroTrain" xml-path="NumeroTrain/text()" />
                <xml-element java-attribute="ci" xml-path="CIPR/text()" />
                <xml-element java-attribute="ch" xml-path="CHPR/text()" />
                <xml-element java-attribute="cr" xml-path="CRPR/text()" />
                <xml-element java-attribute="type" xml-path="Type/text()" />
            </java-attributes>
        </java-type>
    </java-types>
</xml-bindings>