Question

我正在尝试做相反的事：JAXB - Ignore element

那就是我正在尝试使用JAXB将XML解析为POJO，如果 NOT 找到给定元素的匹配Java属性，我希望JAXB失败。我知道我可以做模式验证，但我宁愿不这样做。

示例：

@XmlRootElement(name="Dog")
public class Dog {
    private String name;
    public String getName() {return name;}
    public String setName(String name) {this.name = name};
}

此XML将失败：

<Dog>
<id>blah</id>
<name>Stuff</name>
</Dog>

因为没有id Java属性

Answer 1

您可以利用ValidationEventHandler来获取您要查找的行为。意外元素被视为警告，默认情况下会被忽略。为了支持您的使用案例，您可以提供警告失败的ValdidationEventHandler（见下文）。

<强>演示

package forum10721257;

import java.io.File;
import javax.xml.bind.*;

public class Demo {

    public static void main(String[] args) throws Exception {
        JAXBContext jc = JAXBContext.newInstance(Dog.class);

        File xml = new File("src/forum10721257/input.xml");
        Unmarshaller unmarshaller = jc.createUnmarshaller();
        unmarshaller.setEventHandler(new ValidationEventHandler () {

            @Override
            public boolean handleEvent(ValidationEvent event) {
                return false;
            }

        });
        Dog dog = (Dog) unmarshaller.unmarshal(xml);
    }

}

JAXB RI异常

Exception in thread "main" javax.xml.bind.UnmarshalException: unexpected element (uri:"", local:"id"). Expected elements are <{}name>
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext.handleEvent(UnmarshallingContext.java:647)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.Loader.reportError(Loader.java:243)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.Loader.reportError(Loader.java:238)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.Loader.reportUnexpectedChildElement(Loader.java:105)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.Loader.childElement(Loader.java:90)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.StructureLoader.childElement(StructureLoader.java:236)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext._startElement(UnmarshallingContext.java:483)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext.startElement(UnmarshallingContext.java:465)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.SAXConnector.startElement(SAXConnector.java:135)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.startElement(AbstractSAXParser.java:506)
    at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement(XMLNSDocumentScannerImpl.java:376)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2715)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:607)
    at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:116)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:488)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:835)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:764)
    at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:123)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1210)
    at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:568)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(UnmarshallerImpl.java:202)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal(UnmarshallerImpl.java:174)
    at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:157)
    at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:162)
    at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:171)
    at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:189)
    at forum10721257.Demo.main(Demo.java:26)

EclipseLink JAXB（MOXy）

我们最近将此行为添加到MOXy。您将需要使用EclipseLink 2.4.0或2.3.3。可以从以下位置获取每晚构建：

http://www.eclipse.org/eclipselink/downloads/nightly.php

<强>更新

我需要调整你问题中的Dog类。以下是我使用的内容。

<强>狗

package forum10721257;

import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement(name="Dog")
public class Dog {
    private String name;
    public String getName() {return name;}
    public void setName(String name) {this.name = name;}
}

Answer 2

我能够验证缺少的Java属性（没有模式）的唯一方法是将XML解组到我的POJO，然后使用相同的POJO将其重新编组为XML并进行比较。

下面是一个使用XMLUnit的示例，它有助于忽略顺序和空白问题。

@Test
public void testSerialization() throws Exception {
    XMLUnit.setIgnoreWhitespace(true);

    EventSearchResults r = 
            JAXB.unmarshal(getClass().getResourceAsStream("/EventSearchResults.xml"), 
                    EventSearchResults.class);
    StringWriter sw = new StringWriter();
    JAXB.marshal(r, sw);
    String expected = 
            IOUtils.toString(getClass().getResourceAsStream("/EventSearchResults.xml"), "UTF-8");
    String actual = sw.toString();
    //System.out.println(expected);
    System.out.println(actual);
    assertXMLEqual(expected, actual);
}

这不是理想的，但大部分都适用于单元测试。

在非映射元素上产生JAXB错误

2 个答案: