JAXB:当使用XML模式(.xsd)验证XML文件时,如果验证失败,我可以知道导致它的XML标记吗？

Question

所以当我使用XML模式验证XML文件时,我只能知道它是失败还是通过,如果我想知道它为什么失败,我需要查看错误消息,如

[org.xml.sax.SAXParseException: cvc-complex-type.2.4.a: Invalid content was found starting with element 'City'. One of '{Address1}' is expected.]

在上面的示例中,它失败,因为我缺少标记Address1.我的问题是当验证失败时,我能知道导致失败的标签吗？这是因为我需要为每个重要的缺失标记处理不同的故障.现在我的想法是

FileInputStream inputStream = null;
try{
    SchemaFactory sf = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
    Schema schema = sf.newSchema(new File(config.getXmlSchema()));
    JAXBContext context = JAXBContext.newInstance(PackageLabel.class);
    Unmarshaller unmarshaller = context.createUnmarshaller();
    unmarshaller.setSchema(schema);
    inputStream = new FileInputStream(xmlFile);
    pl = (PackageLabel) unmarshaller.unmarshal(inputStream);
} catch (JAXBException e) {
    if(pl.getAddress1() == null){
         System.out.println("Invalid Mailing Address");
    }
    //EDIT: CANNOT DO THIS, SINCE pl  IS NULL AT THIS POINT
    //Some more logics on how to handle important missing-tags
    ...
}finally{
    if(inputStream != null) inputStream.close();
}  

但是,我不认为内部写入逻辑catch clause是正确的.有什么建议？

编辑

我遵循了Balaise的想法,下面是我在XML缺少Address1时收到的事件

EVENT
SEVERITY:  2
MESSAGE:  cvc-complex-type.2.4.a: Invalid content was found starting with element 'City'. One of '{Address1}' is expected.
LINKED EXCEPTION:  org.xml.sax.SAXParseException: cvc-complex-type.2.4.a: Invalid content was found starting with element 'City'. One of '{Address1}' is expected.
LOCATOR
 LINE NUMBER:  4
 COLUMN NUMBER:  11
 OFFSET:  -1
 OBJECT:  null
 NODE:  null
 URL:  null

然而,无论是NODE和OBJECT是空的,我不能再对什么产生例外,除非我解析异常这是我原来问调查.

Answer 1

你可以利用JAXB ValidationEventHandler.然后可以在Marshaller和的实例上设置实现Unmarshaller:

package blog.jaxb.validation;

import javax.xml.bind.ValidationEvent;
import javax.xml.bind.ValidationEventHandler;

public class MyValidationEventHandler implements ValidationEventHandler {

    public boolean handleEvent(ValidationEvent event) {
        System.out.println("\nEVENT");
        System.out.println("SEVERITY:  " + event.getSeverity());
        System.out.println("MESSAGE:  " + event.getMessage());
        System.out.println("LINKED EXCEPTION:  " + event.getLinkedException());
        System.out.println("LOCATOR");
        System.out.println("    LINE NUMBER:  " + event.getLocator().getLineNumber());
        System.out.println("    COLUMN NUMBER:  " + event.getLocator().getColumnNumber());
        System.out.println("    OFFSET:  " + event.getLocator().getOffset());
        System.out.println("    OBJECT:  " + event.getLocator().getObject());
        System.out.println("    NODE:  " + event.getLocator().getNode());
        System.out.println("    URL:  " + event.getLocator().getURL());
        return true;
    }

}

欲获得更多信息

• http://blog.bdoughan.com/2010/12/jaxb-and-marshalunmarshal-schema.html
• http://bdoughan.blogspot.com/2010/11/validate-jaxb-object-model-with-xml.html