Validator (xsd) for xml in android

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-上瘾入骨i
-上瘾入骨i 2021-01-25 05:09

I have a project with API 10 (2.3.3 version) in Android and i have a problem for the validation of xml with xsd file. This is my code:



        
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  • 2021-01-25 05:55

    Because XML Schema isn't supported on your platform.

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  • 2021-01-25 06:00

    If your question was more than just why? and more of a how can I do this... then the following may be an alternative that you might like.

    I found I was not able to get the regular xerces to work with Android, however I did find Xerces-for-Android, which I got working. The following are details of the setup and some example code. Good luck :)

    The following worked for me:

    1. Create a validation utility.
    2. Get both the xml and xsd into file on the android OS and use the validation utility against it.
    3. Use Xerces-For-Android to do the validation.

    Android does support some packages which we can use, I created my xml validation utility based on: http://docs.oracle.com/javase/1.5.0/docs/api/javax/xml/validation/package-summary.html

    My initial sandbox testing was pretty smooth with java, then I tried to port it over to Dalvik and found that my code did not work. Some things just aren't supported the same with Dalvik, so I made some modifications.

    I found a reference to xerces for android, so I modified my sandbox test of (the following doesn't work with android, the example after this does):

    import java.io.File;
    
    import javax.xml.XMLConstants;
    import javax.xml.parsers.DocumentBuilder;
    import javax.xml.parsers.DocumentBuilderFactory;
    import javax.xml.transform.Source;
    import javax.xml.transform.dom.DOMSource;
    import javax.xml.transform.stream.StreamSource;
    import javax.xml.validation.Schema;
    import javax.xml.validation.SchemaFactory;
    import javax.xml.validation.Validator;
    
    import org.w3c.dom.Document;
    
    /**
     * A Utility to help with xml communication validation.
     */
    public class XmlUtil {
    
        /**
         * Validation method. 
         * Base code/example from: http://docs.oracle.com/javase/1.5.0/docs/api/javax/xml/validation/package-summary.html
         * 
         * @param xmlFilePath The xml file we are trying to validate.
         * @param xmlSchemaFilePath The schema file we are using for the validation. This method assumes the schema file is valid.
         * @return True if valid, false if not valid or bad parse. 
         */
        public static boolean validate(String xmlFilePath, String xmlSchemaFilePath) {
    
            // parse an XML document into a DOM tree
            DocumentBuilder parser = null;
            Document document;
    
            // Try the validation, we assume that if there are any issues with the validation
            // process that the input is invalid.
            try {
                // validate the DOM tree
                parser = DocumentBuilderFactory.newInstance().newDocumentBuilder();
                document = parser.parse(new File(xmlFilePath));
    
                // 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(xmlSchemaFilePath));
                Schema schema = factory.newSchema(schemaFile);
    
                // create a Validator instance, which can be used to validate an instance document
                Validator validator = schema.newValidator();
                validator.validate(new DOMSource(document));
            } catch (Exception e) {
                // Catches: SAXException, ParserConfigurationException, and IOException.
                return false;
            }     
    
            return true;
        }
    }
    

    The above code had to be modified some to work with xerces for android (http://gc.codehum.com/p/xerces-for-android/). You need SVN to get the project, the following are some crib notes:

    download xerces-for-android
        download silk svn (for windows users) from http://www.sliksvn.com/en/download
            install silk svn (I did complete install)
            Once the install is complete, you should have svn in your system path.
            Test by typing "svn" from the command line.
            I went to my desktop then downloaded the xerces project by:
                svn checkout http://xerces-for-android.googlecode.com/svn/trunk/ xerces-for-android-read-only
            You should then have a new folder on your desktop called xerces-for-android-read-only
    

    With the above jar (Eventually I'll make it into a jar, just copied it directly into my source for quick testing. If you wish to do the same, you can making the jar quickly with Ant (http://ant.apache.org/manual/using.html)), I was able to get the following to work for my xml validation:

    import java.io.File;
    import java.io.IOException;
    
    import mf.javax.xml.transform.Source;
    import mf.javax.xml.transform.stream.StreamSource;
    import mf.javax.xml.validation.Schema;
    import mf.javax.xml.validation.SchemaFactory;
    import mf.javax.xml.validation.Validator;
    import mf.org.apache.xerces.jaxp.validation.XMLSchemaFactory;
    
    import org.xml.sax.SAXException;
    
    /**
     * A Utility to help with xml communication validation.
     */public class XmlUtil {
    
        /**
         * Validation method. 
         * 
         * @param xmlFilePath The xml file we are trying to validate.
         * @param xmlSchemaFilePath The schema file we are using for the validation. This method assumes the schema file is valid.
         * @return True if valid, false if not valid or bad parse or exception/error during parse. 
         */
        public static boolean validate(String xmlFilePath, String xmlSchemaFilePath) {
    
            // Try the validation, we assume that if there are any issues with the validation
            // process that the input is invalid.
            try {
                SchemaFactory  factory = new XMLSchemaFactory();
                Source schemaFile = new StreamSource(new File(xmlSchemaFilePath));
                Source xmlSource = new StreamSource(new File(xmlFilePath));
                Schema schema = factory.newSchema(schemaFile);
                Validator validator = schema.newValidator();
                validator.validate(xmlSource);
            } catch (SAXException e) {
                return false;
            } catch (IOException e) {
                return false;
            } catch (Exception e) {
                // Catches everything beyond: SAXException, and IOException.
                e.printStackTrace();
                return false;
            } catch (Error e) {
                // Needed this for debugging when I was having issues with my 1st set of code.
                e.printStackTrace();
                return false;
            }
    
            return true;
        }
    }
    

    Some Side Notes:

    For creating the files, I made a simple file utility to write string to files:

    public static void createFileFromString(String fileText, String fileName) {
        try {
            File file = new File(fileName);
            BufferedWriter output = new BufferedWriter(new FileWriter(file));
            output.write(fileText);
            output.close();
        } catch ( IOException e ) {
           e.printStackTrace();
        }
    }
    

    I also needed to write to an area that I had access to, so I made use of:

    String path = this.getActivity().getPackageManager().getPackageInfo(getPackageName(), 0).applicationInfo.dataDir;   
    

    A little hackish, it works. I'm sure there is a more succinct way of doing this, however I figured I'd share my success, as there weren't any good examples that I found.

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