Develop Reference

Java Validate XML Schema with XSDs that import each other [duplicate]

I'm trying to validate an XML file against a number of different schemas (apologies for the contrived example):
a.xsd
b.xsd
c.xsd
c.xsd in particular imports b.xsd and b.xsd imports a.xsd, using:
<xs:include schemaLocation="b.xsd"/>
I'm trying to do this via Xerces in the following manner:
XMLSchemaFactory xmlSchemaFactory = new XMLSchemaFactory();
Schema schema = xmlSchemaFactory.newSchema(new StreamSource[] { new StreamSource(this.getClass().getResourceAsStream("a.xsd"), "a.xsd"),
new StreamSource(this.getClass().getResourceAsStream("b.xsd"), "b.xsd"),
new StreamSource(this.getClass().getResourceAsStream("c.xsd"), "c.xsd")});
Validator validator = schema.newValidator();
validator.validate(new StreamSource(new StringReader(xmlContent)));
but this is failing to import all three of the schemas correctly resulting in cannot resolve the name 'blah' to a(n) 'group' component.
I've validated this successfully using Python, but having real problems with Java 6.0 and Xerces 2.8.1. Can anybody suggest what's going wrong here, or an easier approach to validate my XML documents?

So just in case anybody else runs into the same issue here, I needed to load a parent schema (and implicit child schemas) from a unit test - as a resource - to validate an XML String. I used the Xerces XMLSchemFactory to do this along with the Java 6 validator.
In order to load the child schema's correctly via an include I had to write a custom resource resolver. Code can be found here:
https://code.google.com/p/xmlsanity/source/browse/src/com/arc90/xmlsanity/validation/ResourceResolver.java
To use the resolver specify it on the schema factory:
xmlSchemaFactory.setResourceResolver(new ResourceResolver());
and it will use it to resolve your resources via the classpath (in my case from src/main/resources). Any comments are welcome on this...

http://www.kdgregory.com/index.php?page=xml.parsing
section 'Multiple schemas for a single document'
My solution based on that document:
URL xsdUrlA = this.getClass().getResource("a.xsd");
URL xsdUrlB = this.getClass().getResource("b.xsd");
URL xsdUrlC = this.getClass().getResource("c.xsd");
SchemaFactory schemaFactory = schemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
//---
String W3C_XSD_TOP_ELEMENT =
"<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>\n"
+ "<xs:schema xmlns:xs=\"http://www.w3.org/2001/XMLSchema\" elementFormDefault=\"qualified\">\n"
+ "<xs:include schemaLocation=\"" +xsdUrlA.getPath() +"\"/>\n"
+ "<xs:include schemaLocation=\"" +xsdUrlB.getPath() +"\"/>\n"
+ "<xs:include schemaLocation=\"" +xsdUrlC.getPath() +"\"/>\n"
+"</xs:schema>";
Schema schema = schemaFactory.newSchema(new StreamSource(new StringReader(W3C_XSD_TOP_ELEMENT), "xsdTop"));

The schema stuff in Xerces is (a) very, very pedantic, and (b) gives utterly useless error messages when it doesn't like what it finds. It's a frustrating combination.
The schema stuff in python may be a lot more forgiving, and was letting small errors in the schema go past unreported.
Now if, as you say, c.xsd includes b.xsd, and b.xsd includes a.xsd, then there's no need to load all three into the schema factory. Not only is it unnecessary, it will likely confuse Xerces and result in errors, so this may be your problem. Just pass c.xsd to the factory, and let it resolve b.xsd and a.xsd itself, which it should do relative to c.xsd.

From the xerces documentation :
http://xerces.apache.org/xerces2-j/faq-xs.html
import javax.xml.transform.Source;
import javax.xml.transform.stream.StreamSource;
import javax.xml.validation.Schema;
import javax.xml.validation.SchemaFactory;
import javax.xml.validation.Validator;
...
StreamSource[] schemaDocuments = /* created by your application */;
Source instanceDocument = /* created by your application */;
SchemaFactory sf = SchemaFactory.newInstance(
"http://www.w3.org/XML/XMLSchema/v1.1");
Schema s = sf.newSchema(schemaDocuments);
Validator v = s.newValidator();
v.validate(instanceDocument);

I faced the same problem and after investigating found this solution. It works for me.
Enum to setup the different XSDs:
public enum XsdFile {
// #formatter:off
A("a.xsd"),
B("b.xsd"),
C("c.xsd");
// #formatter:on
private final String value;
private XsdFile(String value) {
this.value = value;
}
public String getValue() {
return this.value;
}
}
Method to validate:
public static void validateXmlAgainstManyXsds() {
final SchemaFactory schemaFactory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
String xmlFile;
xmlFile = "example.xml";
// Use of Enum class in order to get the different XSDs
Source[] sources = new Source[XsdFile.class.getEnumConstants().length];
for (XsdFile xsdFile : XsdFile.class.getEnumConstants()) {
sources[xsdFile.ordinal()] = new StreamSource(xsdFile.getValue());
}
try {
final Schema schema = schemaFactory.newSchema(sources);
final Validator validator = schema.newValidator();
System.out.println("Validating " + xmlFile + " against XSDs " + Arrays.toString(sources));
validator.validate(new StreamSource(new File(xmlFile)));
} catch (Exception exception) {
System.out.println("ERROR: Unable to validate " + xmlFile + " against XSDs " + Arrays.toString(sources)
+ " - " + exception);
}
System.out.println("Validation process completed.");
}

I ended up using this:
import org.apache.xerces.parsers.SAXParser;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import org.xml.sax.helpers.DefaultHandler;
import java.io.IOException;
.
.
.
try {
SAXParser parser = new SAXParser();
parser.setFeature("http://xml.org/sax/features/validation", true);
parser.setFeature("http://apache.org/xml/features/validation/schema", true);
parser.setFeature("http://apache.org/xml/features/validation/schema-full-checking", true);
parser.setProperty("http://apache.org/xml/properties/schema/external-noNamespaceSchemaLocation", "http://your_url_schema_location");
Validator handler = new Validator();
parser.setErrorHandler(handler);
parser.parse("file:///" + "/home/user/myfile.xml");
} catch (SAXException e) {
e.printStackTrace();
} catch (IOException ex) {
e.printStackTrace();
}
class Validator extends DefaultHandler {
public boolean validationError = false;
public SAXParseException saxParseException = null;
public void error(SAXParseException exception)
throws SAXException {
validationError = true;
saxParseException = exception;
}
public void fatalError(SAXParseException exception)
throws SAXException {
validationError = true;
saxParseException = exception;
}
public void warning(SAXParseException exception)
throws SAXException {
}
}
Remember to change:
1) The parameter "http://your_url_schema_location" for you xsd file location.
2) The string "/home/user/myfile.xml" for the one pointing to your xml file.
I didn't have to set the variable: -Djavax.xml.validation.SchemaFactory:http://www.w3.org/2001/XMLSchema=org.apache.xerces.jaxp.validation.XMLSchemaFactory

Just in case, anybody still come here to find the solution for validating xml or object against multiple XSDs, I am mentioning it here
//Using **URL** is the most important here. With URL, the relative paths are resolved for include, import inside the xsd file. Just get the parent level xsd here (not all included xsds).
URL xsdUrl = getClass().getClassLoader().getResource("my/parent/schema.xsd");
SchemaFactory schemaFactory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
Schema schema = schemaFactory.newSchema(xsdUrl);
JAXBContext jaxbContext = JAXBContext.newInstance(MyClass.class);
Unmarshaller unmarshaller = jaxbContext.createUnmarshaller();
unmarshaller.setSchema(schema);
/* If you need to validate object against xsd, uncomment this
ObjectFactory objectFactory = new ObjectFactory();
JAXBElement<MyClass> wrappedObject = objectFactory.createMyClassObject(myClassObject);
marshaller.marshal(wrappedShipmentMessage, new DefaultHandler());
*/
unmarshaller.unmarshal(getClass().getClassLoader().getResource("your/xml/file.xml"));

If all XSDs belong to the same namespace then create a new XSD and import other XSDs into it. Then in java create schema with the new XSD.
Schema schema = xmlSchemaFactory.newSchema(
new StreamSource(this.getClass().getResourceAsStream("/path/to/all_in_one.xsd"));
all_in_one.xsd :
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:ex="http://example.org/schema/"
targetNamespace="http://example.org/schema/"
elementFormDefault="unqualified"
attributeFormDefault="unqualified">
<xs:include schemaLocation="relative/path/to/a.xsd"></xs:include>
<xs:include schemaLocation="relative/path/to/b.xsd"></xs:include>
<xs:include schemaLocation="relative/path/to/c.xsd"></xs:include>
</xs:schema>

Valiaion of an XML against XSD using java is Showing exception [duplicate]

This question already has an answer here:
How to link XML to XSD using schemaLocation or noNamespaceSchemaLocation?
(1 answer)
Closed 4 years ago.
I am using Analytical Information Markup Language (AnIML) is the emerging ASTM XML standard for analytical chemistry data in my project. I have an xml data which I want to validate against an XSD file.But whenever I run the program it is showing an exception. I am using jav acode. My code is-
public class XMLValidator {
public static final String XML_FILE = "test_data.xml";
public static final String SCHEMA_FILE = "test.xsd";
public static void main(String[] args) {
XMLValidator XMLValidator = new XMLValidator();
boolean valid = XMLValidator.validate(XML_FILE, SCHEMA_FILE);
System.out.printf("%s validation = %b.", XML_FILE, valid);
}
private boolean validate(String xmlFile, String schemaFile) {
SchemaFactory schemaFactory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
try {
Schema schema = schemaFactory.newSchema(new File(schemaFile));
Validator validator = schema.newValidator();
validator.validate(new StreamSource(new File(xmlFile)));
return true;
} catch (SAXException | IOException e) {
e.printStackTrace();
return false;
}
}
My XML file is
Modified XML
<?xml version="1.0" encoding="UTF-8"?>
<AnIML xmlns:xsi="urn:org:astm:animl:schema:core:draft:0.90" xmlns:ds="http://www.w3.org/2000/09/xmldsig#"
xsi:noNamespaceSchemaLocation="https://github.com/AnIML/schemas/blob/master/animl-core.xsd" version="0.90" blu-fmt-v="1">
<ExperimentStepSet>
..
</ExperimentStep>
</ExperimentStepSet>
</AnIML>
The exception I got is
org.xml.sax.SAXParseException; systemId: file:/D:/test/xmlvalidator/test_data.xml; lineNumber: 2; columnNumber: 229; cvc-elt.1: Declaration of element 'AnIML' can not be found.
at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:203)
at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.error(ErrorHandlerWrapper.java:134)
at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:396)
at .....

The XSD file you're using says that the elements must be in namespace urn:org:astm:animl:schema:core:draft:0.90
That can be seen with this attribute in its root:
targetNamespace="urn:org:astm:animl:schema:core:draft:0.90"
Your XML file doesn't use this namespace, nor any other for that matter.
Your XML file needs to comply to the XSD rules to be valid according to this XSD.
A very cheap change to your XML so that it uses the correct namespace required by the XSD, is to just declare this namespace as the default namespace in the root:
<AnIML
xmlns="urn:org:astm:animl:schema:core:draft:0.90"
xmlns:ds="http://www.w3.org/2000/09/xmldsig#"
version="0.90" blu-fmt-v="1">
And all descendant elements will inherit it.
If you still want to keep your previously failing XML Schema validation declarations, it needs to be adapted that way:
<AnIML
xmlns="urn:org:astm:animl:schema:core:draft:0.90"
xmlns:ds="http://www.w3.org/2000/09/xmldsig#"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="urn:org:astm:animl:schema:core:draft:0.90 https://github.com/AnIML/schemas/blob/master/animl-core.xsd"
version="0.90" blu-fmt-v="1">

"Package with uri 'null' not found" while loading XML file using EMF

I am trying to load an XML file using EMF and I am using the following code to do that in XMLArtefactAdapter.java:
constructor():
ResourceSet set = new ResourceSetImpl();
//registering factory
set.getResourceFactoryRegistry()
.getExtensionToFactoryMap()
.put
(Resource.Factory.Registry.DEFAULT_EXTENSION,new XMLResourceFactoryImpl());
parse() method:
//parsing XML
try {
String absolutePath = file.getAbsolutePath();
URI uri = URI.createFileURI(absolutePath);
Resource resource = resourceSet.createResource(uri);
resource.load(Collections.EMPTY_MAP);
System.out.println("LOADED");
} catch (IOException e) {
System.out.println(e.toString());
}
I am executing this code fragment from my Main class:
Path path = Paths.get("C:\\Users\\Srijani\\Desktop\\book.xml");
XMLArtefactAdapter xmlAdapter = new XMLArtefactAdapter(path);
xmlAdapter.parse();
But, I get error while running this code.
org.eclipse.emf.ecore.resource.Resource$IOWrappedException: Package with uri 'null' not found. (file:/C:/Users/Srijani/Desktop/plugin.xml, 3, 9)
Please note the following:
My Plugin.xml
<plugin>
<extension point="org.eclipse.emf.ecore.generated_package">
<!-- #generated simpletree -->
<package
uri="platform:/plugin/com.kaleidoscope.core.aux.simpletree/model/SimpleTree.ecore"
class="SimpleTree.SimpletreePackage"
genModel="model/simpletree.genmodel"/>
</extension>
</plugin>
Any idea why this is happening?
Thanks in Advance!

An EPackage uri is a kind of public identifier for your EPackage. It should not be an eclipse uri.
Usually, the namespace URI is an http url providing some basic informations about the EPackage provider, ePackage name and version.
eg :
<extension point="org.eclipse.emf.ecore.generated_package">
<package
uri="http://www.eclipse.org/emf/2002/Ecore"
class="org.eclipse.emf.ecore.EcorePackage"
genModel="model/Ecore.genmodel"/>
</extension>
You should :
change your EPackage nsUri with an identifier for your EPackage,
regenerate the EMF code,
and merge your plugin.xml and plugin.xml_gen files to synchronize your nsURI value.

Java: string xml validation against xsd that include another xsd

Update 1: New Validation method throws new error, see below.
Update 2: i have checked the xml files with xml spy. No errors there.
Hope somebody see where iam wrong.
i'm currently trying to validate xml file against an xsd which includes another xsd. I don' know if my xsds or the java code is faulty. I dont have the xml/xsd files stored, i get them as a base64 string from the server. Hope somebody can help.
I get the fllowing error:
org.xml.sax.SAXParseException; lineNumber: 81; columnNumber: 104; src-resolve: Cannot resolve the name 'ServiceSpecificationSchema:ServiceIdentifier' to a(n) 'type definition' component.
-ServiceSpecificationSchema.xsd
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<schema xmlns="http://www.w3.org/2001/XMLSchema" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:ServiceSpecificationSchema="http://example.org/ServiceSpecificationSchema.xsd" targetNamespace="http://example.org/ServiceSpecificationSchema.xsd" version="1.0" xml:lang="EN">
<include schemaLocation="ServiceBaseTypesSchema.xsd"/>
<element name="serviceSpecification" type="ServiceSpecificationSchema:ServiceSpecification">
<unique name="serviceDataModelTypeKey">
<selector xpath=".//xs:*"/>
<field xpath="#name"/>
</unique>
<keyref name="serviceDataModelReturnValueTypeKeyRef" refer="ServiceSpecificationSchema:serviceDataModelTypeKey">
<selector xpath=".//ServiceSpecificationSchema:returnValueType"/>
<field xpath="ServiceSpecificationSchema:typeReference"/>
</keyref>
<keyref name="serviceDataModelParameterTypeTypeKeyRef" refer="ServiceSpecificationSchema:serviceDataModelTypeKey">
<selector xpath=".//ServiceSpecificationSchema:parameterType"/>
<field xpath="ServiceSpecificationSchema:typeReference"/>
</keyref>
</element>
<complexType name="ServiceSpecification">
<all>
<element name="id" type="ServiceSpecificationSchema:ServiceIdentifier" minOccurs="1" maxOccurs="1"/>
.....
ServiceBaseTypeSchema:
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<schema xmlns="http://www.w3.org/2001/XMLSchema" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:ServiceSpecificationSchema="http://example.org/ServiceSpecificationSchema.xsd" targetNamespace="http://example/ServiceSpecificationSchema.xsd" version="1.0" xml:lang="EN">
...
<simpleType name="ServiceIdentifier">
<restriction base="string"/>
</simpleType>
...
</schema>
Java Validator
public void validate(String inputXml, String XSD, String XSD2)
throws SAXException, IOException {
try {
byte[] decoded = Base64.decodeBase64(XSD);
XSD = new String(decoded, "UTF-8");
byte[] decoded2 = Base64.decodeBase64(XSD2);
XSD2 = new String(decoded2, "UTF-8");
SchemaFactory factory = SchemaFactory.newInstance("http://www.w3.org/2001/XMLSchema");
Schema schema = factory.newSchema(new SAXSource[]
{
(new SAXSource(new InputSource(new StringReader(XSD)))),
(new SAXSource(new InputSource(new StringReader(XSD2))))
});
Validator validator = schema.newValidator();
validator.validate(new StreamSource(new StringReader(inputXml)));
} catch (SAXException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
I found another possible solution, but it still don't work. With the following method, the exeption is thrown, wenn validating the xsds against the xml. The line of the excetion depends on the used xml. In the Example on the bottom, the error is in line 2. -> Error: Cannot find the declaration of element 'ServiceSpecificationSchema:serviceSpecification'
I think: 1. My java code is faulty or 2. all the xml files are.
New Java Validator:
byte[] decoded = Base64.decodeBase64(XSD);
byte[] decoded2 = Base64.decodeBase64(XSD2);
SchemaFactory factory = SchemaFactory.newInstance("http://www.w3.org/2001/XMLSchema");
InputStream impFis = new ByteArrayInputStream(decoded2);
InputStream mainFis = new ByteArrayInputStream(decoded);
Source main = new StreamSource(mainFis);
Source imp = new StreamSource(impFis);
Source[] schemaFiles = new Source[] {imp, main};
Schema schema = factory.newSchema(schemaFiles);
Validator validator = schema.newValidator();
validator.validate(new StreamSource(new StringReader(inputXml)));
Example XML file:
<?xml version="1.0" encoding="UTF-8"?>
<ServiceSpecificationSchema:serviceSpecification
xmlns:ServiceSpecificationSchema="http://example.org/ServiceSpecificationSchema.xsd"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://example.org/ServiceSpecificationSchema.xsd">
.....

Finally i found a solution. Thestandard method does not resolve included or imported files from the start. To resolve the included files i used the LSResourceResolver.
This works for me:
#Service
public class ResourceResolverImpl implements LSResourceResolver {
private ILoadFromSRService iLoadFromSRService;
#Autowired
public ResourceResolverImpl(ILoadFromSRService iLoadFromSRService){
this.iLoadFromSRService = iLoadFromSRService;
}
public LSInput resolveResource(String type,
String namespaceURI,
String publicId,
String systemId,
String baseURI) {
String string =iLoadFromSRService.getServiceBaseTypeSchema();
string = string.replace("\n", "").replace("\t", "");
InputStream resourceAsStream = new ByteArrayInputStream( string.getBytes());
return new LSInputImpl(publicId, systemId, resourceAsStream);
}
}

How to validate an XML file against an XSD file?

I'm generating some xml files that needs to conform to an xsd file that was given to me. How should I verify they conform?

The Java runtime library supports validation. Last time I checked this was the Apache Xerces parser under the covers. You should probably use a javax.xml.validation.Validator.
import javax.xml.XMLConstants;
import javax.xml.transform.Source;
import javax.xml.transform.stream.StreamSource;
import javax.xml.validation.*;
import java.net.URL;
import org.xml.sax.SAXException;
//import java.io.File; // if you use File
import java.io.IOException;
...
URL schemaFile = new URL("http://host:port/filename.xsd");
// webapp example xsd:
// URL schemaFile = new URL("http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd");
// local file example:
// File schemaFile = new File("/location/to/localfile.xsd"); // etc.
Source xmlFile = new StreamSource(new File("web.xml"));
SchemaFactory schemaFactory = SchemaFactory
.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
try {
Schema schema = schemaFactory.newSchema(schemaFile);
Validator validator = schema.newValidator();
validator.validate(xmlFile);
System.out.println(xmlFile.getSystemId() + " is valid");
} catch (SAXException e) {
System.out.println(xmlFile.getSystemId() + " is NOT valid reason:" + e);
} catch (IOException e) {}
The schema factory constant is the string http://www.w3.org/2001/XMLSchema which defines XSDs. The above code validates a WAR deployment descriptor against the URL http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd but you could just as easily validate against a local file.
You should not use the DOMParser to validate a document (unless your goal is to create a document object model anyway). This will start creating DOM objects as it parses the document - wasteful if you aren't going to use them.

Here's how to do it using Xerces2. A tutorial for this, here (req. signup).
Original attribution: blatantly copied from here:
import org.apache.xerces.parsers.DOMParser;
import java.io.File;
import org.w3c.dom.Document;
public class SchemaTest {
public static void main (String args[]) {
File docFile = new File("memory.xml");
try {
DOMParser parser = new DOMParser();
parser.setFeature("http://xml.org/sax/features/validation", true);
parser.setProperty(
"http://apache.org/xml/properties/schema/external-noNamespaceSchemaLocation",
"memory.xsd");
ErrorChecker errors = new ErrorChecker();
parser.setErrorHandler(errors);
parser.parse("memory.xml");
} catch (Exception e) {
System.out.print("Problem parsing the file.");
}
}
}

We build our project using ant, so we can use the schemavalidate task to check our config files:
<schemavalidate>
<fileset dir="${configdir}" includes="**/*.xml" />
</schemavalidate>
Now naughty config files will fail our build!
http://ant.apache.org/manual/Tasks/schemavalidate.html

Since this is a popular question, I will point out that java can also validate against "referred to" xsd's, for instance if the .xml file itself specifies XSD's in the header, using xsi:schemaLocation or xsi:noNamespaceSchemaLocation (or xsi for particular namespaces) ex:
<document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation="http://www.example.com/document.xsd">
...
or schemaLocation (always a list of namespace to xsd mappings)
<document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.example.com/my_namespace http://www.example.com/document.xsd">
...
The other answers work here as well, because the .xsd files "map" to the namespaces declared in the .xml file, because they declare a namespace, and if matches up with the namespace in the .xml file, you're good. But sometimes it's convenient to be able to have a custom resolver...
From the javadocs: "If you create a schema without specifying a URL, file, or source, then the Java language creates one that looks in the document being validated to find the schema it should use. For example:"
SchemaFactory factory = SchemaFactory.newInstance("http://www.w3.org/2001/XMLSchema");
Schema schema = factory.newSchema();
and this works for multiple namespaces, etc.
The problem with this approach is that the xmlsns:xsi is probably a network location, so it'll by default go out and hit the network with each and every validation, not always optimal.
Here's an example that validates an XML file against any XSD's it references (even if it has to pull them from the network):
public static void verifyValidatesInternalXsd(String filename) throws Exception {
InputStream xmlStream = new new FileInputStream(filename);
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setValidating(true);
factory.setNamespaceAware(true);
factory.setAttribute("http://java.sun.com/xml/jaxp/properties/schemaLanguage",
"http://www.w3.org/2001/XMLSchema");
DocumentBuilder builder = factory.newDocumentBuilder();
builder.setErrorHandler(new RaiseOnErrorHandler());
builder.parse(new InputSource(xmlStream));
xmlStream.close();
}
public static class RaiseOnErrorHandler implements ErrorHandler {
public void warning(SAXParseException e) throws SAXException {
throw new RuntimeException(e);
}
public void error(SAXParseException e) throws SAXException {
throw new RuntimeException(e);
}
public void fatalError(SAXParseException e) throws SAXException {
throw new RuntimeException(e);
}
}
You can avoid pulling referenced XSD's from the network, even though the xml files reference url's, by specifying the xsd manually (see some other answers here) or by using an "XML catalog" style resolver. Spring apparently also can intercept the URL requests to serve local files for validations. Or you can set your own via setResourceResolver, ex:
Source xmlFile = new StreamSource(xmlFileLocation);
SchemaFactory schemaFactory = SchemaFactory
.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
Schema schema = schemaFactory.newSchema();
Validator validator = schema.newValidator();
validator.setResourceResolver(new LSResourceResolver() {
#Override
public LSInput resolveResource(String type, String namespaceURI,
String publicId, String systemId, String baseURI) {
InputSource is = new InputSource(
getClass().getResourceAsStream(
"some_local_file_in_the_jar.xsd"));
// or lookup by URI, etc...
return new Input(is); // for class Input see
// https://stackoverflow.com/a/2342859/32453
}
});
validator.validate(xmlFile);
See also here for another tutorial.
I believe the default is to use DOM parsing, you can do something similar with SAX parser that is validating as well saxReader.setEntityResolver(your_resolver_here);

Using Java 7 you can follow the documentation provided in package description.
// create a SchemaFactory capable of understanding WXS schemas
SchemaFactory factory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
// load a WXS schema, represented by a Schema instance
Source schemaFile = new StreamSource(new File("mySchema.xsd"));
Schema schema = factory.newSchema(schemaFile);
// create a Validator instance, which can be used to validate an instance document
Validator validator = schema.newValidator();
// validate the DOM tree
try {
validator.validate(new StreamSource(new File("instance.xml"));
} catch (SAXException e) {
// instance document is invalid!
}

If you have a Linux-Machine you could use the free command-line tool SAXCount. I found this very usefull.
SAXCount -f -s -n my.xml
It validates against dtd and xsd.
5s for a 50MB file.
In debian squeeze it is located in the package "libxerces-c-samples".
The definition of the dtd and xsd has to be in the xml! You can't config them separately.

With JAXB, you could use the code below:
#Test
public void testCheckXmlIsValidAgainstSchema() {
logger.info("Validating an XML file against the latest schema...");
MyValidationEventCollector vec = new MyValidationEventCollector();
validateXmlAgainstSchema(vec, inputXmlFileName, inputXmlSchemaName, inputXmlRootClass);
assertThat(vec.getValidationErrors().isEmpty(), is(expectedValidationResult));
}
private void validateXmlAgainstSchema(final MyValidationEventCollector vec, final String xmlFileName, final String xsdSchemaName, final Class<?> rootClass) {
try (InputStream xmlFileIs = Thread.currentThread().getContextClassLoader().getResourceAsStream(xmlFileName);) {
final JAXBContext jContext = JAXBContext.newInstance(rootClass);
// Unmarshal the data from InputStream
final Unmarshaller unmarshaller = jContext.createUnmarshaller();
final SchemaFactory sf = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
final InputStream schemaAsStream = Thread.currentThread().getContextClassLoader().getResourceAsStream(xsdSchemaName);
unmarshaller.setSchema(sf.newSchema(new StreamSource(schemaAsStream)));
unmarshaller.setEventHandler(vec);
unmarshaller.unmarshal(new StreamSource(xmlFileIs), rootClass).getValue(); // The Document class is the root object in the XML file you want to validate
for (String validationError : vec.getValidationErrors()) {
logger.trace(validationError);
}
} catch (final Exception e) {
logger.error("The validation of the XML file " + xmlFileName + " failed: ", e);
}
}
class MyValidationEventCollector implements ValidationEventHandler {
private final List<String> validationErrors;
public MyValidationEventCollector() {
validationErrors = new ArrayList<>();
}
public List<String> getValidationErrors() {
return Collections.unmodifiableList(validationErrors);
}
#Override
public boolean handleEvent(final ValidationEvent event) {
String pattern = "line {0}, column {1}, error message {2}";
String errorMessage = MessageFormat.format(pattern, event.getLocator().getLineNumber(), event.getLocator().getColumnNumber(),
event.getMessage());
if (event.getSeverity() == ValidationEvent.FATAL_ERROR) {
validationErrors.add(errorMessage);
}
return true; // you collect the validation errors in a List and handle them later
}
}

One more answer: since you said you need to validate files you are generating (writing), you might want to validate content while you are writing, instead of first writing, then reading back for validation. You can probably do that with JDK API for Xml validation, if you use SAX-based writer: if so, just link in validator by calling 'Validator.validate(source, result)', where source comes from your writer, and result is where output needs to go.
Alternatively if you use Stax for writing content (or a library that uses or can use stax), Woodstox can also directly support validation when using XMLStreamWriter. Here's a blog entry showing how that is done:

If you are generating XML files programatically, you may want to look at the XMLBeans library. Using a command line tool, XMLBeans will automatically generate and package up a set of Java objects based on an XSD. You can then use these objects to build an XML document based on this schema.
It has built-in support for schema validation, and can convert Java objects to an XML document and vice-versa.
Castor and JAXB are other Java libraries that serve a similar purpose to XMLBeans.

Using Woodstox, configure the StAX parser to validate against your schema and parse the XML.
If exceptions are caught the XML is not valid, otherwise it is valid:
// create the XSD schema from your schema file
XMLValidationSchemaFactory schemaFactory = XMLValidationSchemaFactory.newInstance(XMLValidationSchema.SCHEMA_ID_W3C_SCHEMA);
XMLValidationSchema validationSchema = schemaFactory.createSchema(schemaInputStream);
// create the XML reader for your XML file
WstxInputFactory inputFactory = new WstxInputFactory();
XMLStreamReader2 xmlReader = (XMLStreamReader2) inputFactory.createXMLStreamReader(xmlInputStream);
try {
// configure the reader to validate against the schema
xmlReader.validateAgainst(validationSchema);
// parse the XML
while (xmlReader.hasNext()) {
xmlReader.next();
}
// no exceptions, the XML is valid
} catch (XMLStreamException e) {
// exceptions, the XML is not valid
} finally {
xmlReader.close();
}
Note: If you need to validate multiple files, you should try to reuse your XMLInputFactory and XMLValidationSchema in order to maximize the performance.

Are you looking for a tool or a library?
As far as libraries goes, pretty much the de-facto standard is Xerces2 which has both C++ and Java versions.
Be fore warned though, it is a heavy weight solution. But then again, validating XML against XSD files is a rather heavy weight problem.
As for a tool to do this for you, XMLFox seems to be a decent freeware solution, but not having used it personally I can't say for sure.

Validate against online schemas
Source xmlFile = new StreamSource(Thread.currentThread().getContextClassLoader().getResourceAsStream("your.xml"));
SchemaFactory factory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
Schema schema = factory.newSchema(Thread.currentThread().getContextClassLoader().getResource("your.xsd"));
Validator validator = schema.newValidator();
validator.validate(xmlFile);
Validate against local schemas
Offline XML Validation with Java

I had to validate an XML against XSD just one time, so I tried XMLFox. I found it to be very confusing and weird. The help instructions didn't seem to match the interface.
I ended up using LiquidXML Studio 2008 (v6) which was much easier to use and more immediately familiar (the UI is very similar to Visual Basic 2008 Express, which I use frequently). The drawback: the validation capability is not in the free version, so I had to use the 30 day trial.