How to generate xml from xsd schema?

Question

I am having xsd schema..How can I generate the xml by using this schema programmatically in java..? and it should be dynamic ,means I can give any schema. Is there any library available to do same.? I have alrady seen the other post also,but unfortunately it did not suit me.. please give tour ideas....??? I am not finding any approach to do same.

Answer 1

XPath is not a tool for generating XML. I'm afraid you're trying to accomplish your goal with the wrong tools. So, I think the answer to your question is: you can't.

Answer 2

Take a look at this link :

JAVA: Build XML document using XPath expressions

And go through this link under the XPath heading :

http://www.vogella.de/articles/JavaXML/article.html

I think this should help you out...:)

Answer 3

The following code performs validation as per your need, and also tells you the line number where the error occurred during parsing You will need following jars to run this code

Only code change needed is at validateSchema() method where request response args need to be replaced with a string representation of your xml and String representation of your XSD.

resolver.jar, xml-apis.jar, serializer.jar, xercesImpl.jar

import org.apache.xerces.parsers.SAXParser;
import org.apache.xerces.xni.Augmentations;
import org.apache.xerces.xni.NamespaceContext;
import org.apache.xerces.xni.XMLLocator;
import org.apache.xerces.xni.XNIException;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import org.xml.sax.helpers.DefaultHandler;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Performs validation on XML based on the XSD. Overrides the
 * {@link SAXParser}.
 *
 *
 */
public class ValidateSchema extends SAXParser {

  /**
   * Container for current line and coloum number being parsed in the XML.
   */
  private XMLLocator locator;

  /**
   * Default public constructor.
   */
  public ValidateSchema() {
    super();
  }

  /**
   * Used for obtaining the {@link XMLLocator} locator object.
   */
  @Override
  public void startDocument(
      XMLLocator locator, String encoding, NamespaceContext namespaceContext, Augmentations augs)
      throws XNIException {
    this.locator = locator;
    super.startDocument(locator, encoding, namespaceContext, augs);
  }

  /**
   * Validates the XML against the provided XSD.
   *
   * @param req HttpServletRequest object.
   * @param resp HttpServletResponse object.
   * @throws IOException
   */
  public void validateSchema(HttpServletRequest req, HttpServletResponse resp)
      throws IOException {
    String content = req.getParameter("data");
    String selectbox = req.getParameter("selectbox");
    content = content.trim();

    // Convert the XML string to byte stream.
    InputStream is = new ByteArrayInputStream(content.getBytes());

    try {
      this.setFeature(Constants.VALIDATION_PROP, true);
      this.setFeature(Constants.SCHEMA_PROP, true);
      this.setFeature(Constants.DYNAMIC_PROP, true);
      this.setFeature(Constants.SCHEMA_CHECKING_PROP, true);
      if("1".equalsIgnoreCase(selectbox)) {
    this.setProperty(Constants.SCHEMA_LOC,"oem.xsd" );
      } else if("2".equalsIgnoreCase(selectbox)) {
    this.setProperty(Constants.SCHEMA_LOC,"carrier.xsd" );
      }

      Validator handler = new Validator();
      this.setErrorHandler(handler);

      InputSource isp = new InputSource();
      isp.setByteStream(is);
      isp.setEncoding("UTF-8");
      this.parse(isp);

      if (handler.validationError == true) {
    StringBuffer errorMessage = new StringBuffer(512);
    errorMessage
        .append("<div style='background: #ffebe6;border: 0px solid #ffe0d7;color:#c10000;height:60px;padding: 5px;'>")
        .append(Constants.INVALID_XML_DOCUMENT)
        .append(" LineNo: ")
        .append(handler.saxParseException.getLineNumber())
        .append(" ColumnNo: ")
        .append(handler.saxParseException.getColumnNumber())
        .append("<br/>")
        .append(handler.validationError)
        .append(handler.saxParseException.getMessage())
        .append("</div>");
    System.out.println( errorMessage );
      } else {
    StringBuffer validMsg = new StringBuffer(512);
    validMsg.append("<div style='background: #ebeff9;border: 0px solid #6b90da;height:60px;padding: 5px;'>")
    .append(Constants.VALID_XML_DOCUMENT).append("</div>");
    System.out.println( validMsg );
      }
    } catch (SAXException e) {
      StringBuffer errorMessage = new StringBuffer(512);
      errorMessage
      .append("<div style='background: #ffebe6;border: 0px solid #ffe0d7;color:#c10000;height:60px;padding: 5px;'>")
      .append(Constants.INVALID_XML_DOCUMENT)
      .append(" LineNo: ")
      .append(this.locator.getLineNumber())
      .append(" ColumnNo: ")
      .append(this.locator.getColumnNumber())
      .append(" <br/>")
      .append(e.getMessage())
      .append("</div>");
    System.out.println( errorMessage );
    } catch (Exception e) {
      StringBuffer errorMessage = new StringBuffer(512);
      errorMessage
      .append("<div style='background: #ffebe6;border: 1px solid #ffe0d7;color:#c10000;height:60px;padding: 5px;'>")
      .append(Constants.INVALID_XML_DOCUMENT)
      .append(" <br/>")
      .append(e.getMessage())
      .append("</div>");
     System.out.println( errorMessage );
    }
  }

  /**
   * Writes back the response to client.
   * 
   * @param msg Response message.
   * @param resp HttpServletResponse object.
   * @throws IOException
   */
  private void responseWrite(
      String msg, HttpServletResponse resp) throws IOException {
    resp.setContentType("text/html");
    resp.getWriter().write(msg);
  }

  /**
   * Custom handler for Errors while parsing documents.
   */
  private class Validator extends DefaultHandler {
    public boolean validationError = false;
    public SAXParseException saxParseException = null;

    /**
     * @throws SAXException
     */
    @Override
    public void error(SAXParseException exception) throws SAXException {
      validationError = true;
      saxParseException = exception;
    }

    /**
     * @throws SAXException
     */
    @Override
    public void fatalError(SAXParseException exception) throws SAXException {
      validationError = true;
      saxParseException = exception;
    }

    /**
     * @throws SAXException
     */
    @Override
    public void warning(SAXParseException exception) throws SAXException {
    }
  }
}

Constants.Java contains the validation properties that you need to specify

public final class Constants {

public static final String VALIDATION_PROP = "http://xml.org/sax/features/validation";
public static final String SCHEMA_PROP = "http://apache.org/xml/features/validation/schema";
public static final String DYNAMIC_PROP = "http://apache.org/xml/features/validation/dynamic";
public static final String SCHEMA_CHECKING_PROP =
    "http://apache.org/xml/features/validation/schema-full-checking";
public static final String SCHEMA_LOC =
    "http://apache.org/xml/properties/schema/external-noNamespaceSchemaLocation";
public static final String VALID_XML_DOCUMENT = "The above XML is valid.";
public static final String INVALID_XML_DOCUMENT = "The Document has error at:";

}