XML Validation

[Jeff Storey]

Hi, typically in the past when I have validated XML documents, I've done something like this:

DOMParser parser = new DOMParser();
parser.setFeature("http://xml.org/sax/features/validation", true); 
parser.setProperty(                        "http://apache.org/xml/properties/schema/external-noNamespaceSchemaLocation",
                         "http:\\whatever:xx\whatever\sms.dtd""); 

Recently though I've started using the Java XML Validation API included with Java 5+. It seems much easier to use the Java XML validation API rather than the DOMParser's validation because 1) the API is simpler and 2) I can easily switch parsers and validation types (i.e. xsd or dtd).

Is there a disadvantage to using the Java XML validation API? I can't see why I wouldn't.

Thanks,
Jeff

[Ulf Dittmer]

Yes, you should use javax.xml... classes, and not rely on any Apache-specific settings or classes. Those had their use before this stuff was standardized as part of JAXP, but now there's no real need to use them any more. (And, indeed, a downside since it makes it harder to switch parsers, should you ever need to do that.)

An example of the canonical way to validate XML is at http://faq.javaranch.com/java/HowToValidateXmlAgainstAnySchema
[ February 20, 2008: Message edited by: Ulf Dittmer ]

[Jeff Storey]

When doing my XML parsing though, I still use other parsers, not the JAXP parsers (i.e. JDOM). Is it a problem to mix and match like that (i.e. use JDOM for reading/writing but using JAXP for validating?)

[Ulf Dittmer]

I wouldn't think so. They all use the same parsers underneath anyway. None of those APIs (DOM, XOM, JDOM, dom4j, Jaxen, ...) have their own parsers; they all rely on whatever parser JAXP provides. They may have config settings to override the JAXP parser setting, but you'd still need to provide one for them.
[ February 20, 2008: Message edited by: Ulf Dittmer ]

[Jeff Storey]

Ulf,

A belated thanks on this topic. I've become a bit more familiar with the JAXP API and it is quite useful. Thanks again.

Jeff

[Krithi Raghu]

Hi...
I am trying to validate an xml using JAXP.

This is my input xml

 <?xml version="1.0" encoding="UTF-8" ?> 
<att:Purchase xmlns:att='http://order.purchase.com/validate'>
<Item>
<Name>Apple</Name>
<Quantity>2</Quantity>
</Item>
</att:Purchase>

When i try to validate this XML, I am getting the following error

[error] org.xml.sax.SAXParseException: cvc-elt.1: Cannot find the declaration of element 'att  :p  urchase'.
Parsing XML failed due to a org.xml.sax.SAXParseException:cvc-elt.1: Cannot find the declaration of element 'att  :p  urchase'.  

This is my xsd

 <?xml version="1.0" encoding="ISO-8859-1" ?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
    xmlns="http://order.purchase.com/validate"
    targetNamespace="http://order.purchase.com/validate"
    elementFormDefault="unqualified">
 
    <xsd:element name="Purchase">
        <xsd:complexType>
          <xsd:sequence minOccurs="1"> 
              <xsd:element name="Item" type="order_item"/>
          </xsd:sequence> 
        </xsd:complexType> 
    </xsd:element>
 
    <xsd:complexType name="order_item">
        <xsd:sequence> 
    <xsd:element name="Name" type="xsd:string"/>
    <xsd:element name="Quantity" type="xsd:string"/>
        </xsd:sequence> 
    </xsd:complexType>
</xsd:schema>   

Could you please guide me where I am going wrong...
Thanks in advance...

[ May 13, 2008: Message edited by: Shanthi Murugeson ]

[ May 13, 2008: Message edited by: Shanthi Murugeson ]
[ May 13, 2008: Message edited by: Shanthi Murugeson ]

[Ulf Dittmer]

The XML snippet you posted is not valid XML - it uses single quotes around attribute value instead of double quotes.