Java API to parse XSD schema file [closed]

Answer 1

Depends what your specific requirements are. This page gives a good overview of the major options and the use cases they support.

One thing to think about: Depending on the platform you are deploying to and other frameworks you are using, there may already be various APIs in your dependency tree (xerces is particularly common in App Servers for example). Watch out for version conflicts which can be a nightmare to isolate and debug.

Answer 2

public class XsdElements {
    public static void main(String args[]) { 
        try { 
            // parse the document
            DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance();
            DocumentBuilder docBuilder = docBuilderFactory.newDocumentBuilder();
            Document doc = docBuilder.parse (new File("C:/Users/rb054/Desktop/Descriptor.1.5.1.xsd")); 
            NodeList list = doc.getElementsByTagName("xs:element"); 

            //loop to print data
            for(int i = 0 ; i < list.getLength(); i++)
            {
                Element first = (Element)list.item(i);
                if(first.hasAttributes())
                {
                    String nm = first.getAttribute("name"); 
                    System.out.println(nm); 
                    String nm1 = first.getAttribute("type"); 
                    System.out.println(nm1); 
                }
            }
        } 
        catch (ParserConfigurationException e) 
        {
            e.printStackTrace();
        }
        catch (SAXException e) 
        { 
            e.printStackTrace();
        }
        catch (IOException ed) 
        {
            ed.printStackTrace();
        }
    }
}

Answer 3

As mentioned, a schema is itself valid XML. What do you want to load it for, validation? If so then there are some handy classes in the javax.xml.validation package.

Answer 4

We have tended to use Apache Xerces http://xerces.apache.org/. Works really well for us.

Answer 5

You can use XMLBeans http://xmlbeans.apache.org. For most use cases around XML/Java binding people seem to be moving to JAXB since it is built in. But for what you want to do, XMLBeans provides access to some great high level data structures that represent schemae in a way that is easy to traverse.

You can start with something like...

SchemaTypeSystem sts = XmlBeans.compileXsd(new XmlObject[] {
    XmlObject.Factory.parse(xsdFile) }, XmlBeans.getBuiltinTypeSystem(), null);

From there you should be able to figure out how to drill into the SchemaTypeSystem from the JavaDoc.

If someone knows of an alternative that is as convenient and relatively supported, it would be great to know about it. I'm actively looking.

Answer 6

Using standard JDK 6:

System.setProperty(DOMImplementationRegistry.PROPERTY, "com.sun.org.apache.xerces.internal.dom.DOMXSImplementationSourceImpl");
DOMImplementationRegistry registry = DOMImplementationRegistry.newInstance(); 
com.sun.org.apache.xerces.internal.impl.xs.XSImplementationImpl impl = (XSImplementationImpl) registry.getDOMImplementation("XS-Loader");
XSLoader schemaLoader = impl.createXSLoader(null);
XSModel model = schemaLoader.loadURI("src/test/resources/my.xsd");