使非映射的元素

Question

我試圖做的相反JAXB錯誤：JAXB - Ignore element

那就是我試圖用JAXB解析XML的POJO，我想JAXB如果確實不許失敗找到給定元素的匹配Java屬性。我知道我可以做架構驗證，但我寧願不這樣做。

例子：

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

此XML會失敗：

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

因爲沒有id Java屬性

Answer 1

我已經能夠確認失蹤的Java性能的唯一途徑（W/o模式）是將XML解組到我的POJO，然後使用相同的POJO將其重新編碼爲XML並進行比較。

下面是一個使用XMLUnit的示例，它有助於忽略順序和空白問題。

@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); 
} 

這並不理想，但大多數情況下適用於單元測試。

Answer 2

您可以利用ValidationEventHandler來獲得您正在查找的行爲。意外的元素被視爲默認情況下被忽略的警告。爲了支持您的使用案例，您可以提供ValdidationEventHandler，該警告無效（請參閱下文）。

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異常

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) 

的EclipseLink JAXB（莫西）

我們最近增加了這種行爲莫西。您將需要使用EclipseLink 2.4.0或2.3.3。每晚構建可從以下位置獲得：

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

---

UPDATE

我需要從你的問題捏捏Dog類。以下是我用過的。

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;} 
}