Java/XML/EntityResolver

Getting the Value of an Entity Reference in a DOM Document

   <source lang="java">
  

import java.io.File; import javax.xml.parsers.DocumentBuilderFactory; import org.w3c.dom.rument; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.EntityReference; import org.w3c.dom.Text; public class Main {

 public static void main(String[] argv) throws Exception {
   DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
   factory.setValidating(true);
   factory.setExpandEntityReferences(false);
   Document doc = factory.newDocumentBuilder().parse(new File("filename"));
   Element root = doc.getDocumentElement();
   EntityReference eref = (EntityReference) root.getFirstChild();
   Comment comment = (Comment) eref.getFirstChild(); 
   Element elem = (Element) eref.getFirstChild().getNextSibling(); 
   Text text = (Text) eref.getLastChild(); 
 }

}

 </source>
   
  
 
  

implements EntityResolver

   <source lang="java">
  

import java.io.IOException; import org.xml.sax.EntityResolver; import org.xml.sax.InputSource; import org.xml.sax.SAXException; public class SimpleEntityResolver implements EntityResolver {

 private static final String USAGE_TERMS_ID = "http://www.n.ru/t.xml";
 private static final String USAGE_TERMS_LOCAL_URI = "C:\\t.xml";
 public InputSource resolveEntity(String publicID, String systemID) throws IOException,
     SAXException {
   if (systemID.equals(USAGE_TERMS_ID)) {
     return new InputSource(USAGE_TERMS_LOCAL_URI);
   }
   return null;
 }

}

 </source>
   
  
 
  

Intercepting All Accesses to External Entities During XML SAX Parsing

   <source lang="java">
  

import java.io.File; import java.io.FileReader; import java.net.URI; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import org.w3c.dom.Document; import org.xml.sax.EntityResolver; import org.xml.sax.InputSource; public class Main {

 public static void main(String[] argv) throws Exception {
   DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
   builder.setEntityResolver(new MyResolver());
   Document doc = builder.parse(new File("infilename.xml"));
 }

} class MyResolver implements EntityResolver {

 public InputSource resolveEntity(String publicId, String systemId) {
   try {
     URI uri = new URI(systemId);
     if ("file".equals(uri.getScheme())) {
       String filename = uri.getSchemeSpecificPart();
       return new InputSource(new FileReader(filename));
     }
   } catch (Exception e) {
   }
   return null;
 }

}

 </source>
   
  
 
  

Preventing Expansion of Entity References While Parsing an XML File

   <source lang="java">
  

import java.io.File; import javax.xml.parsers.DocumentBuilderFactory; import org.w3c.dom.Document; public class Main {

 public static void main(String[] argv) throws Exception{
   DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
   factory.setValidating(true);
   // Prevent expansion of entity references
   factory.setExpandEntityReferences(false);
   // Create the builder and parse the file
   Document doc = factory.newDocumentBuilder().parse(new File("filename"));
 }

}

 </source>
   
  
 
  

Resolves an entity reference or character reference to its value.

   <source lang="java">

/*

* Copyright Aduna (http://www.aduna-software.ru/) (c) 1997-2006.
*
* Licensed under the Aduna BSD-style license.
*/

public class Utils {

 /**
  * Resolves an entity reference or character reference to its value. 
  *
  * @param entName The "name" of the reference. This is the string between
  * & and ;, e.g. amp, quot, #65 or #x41.
  * @return The value of the supplied reference, or the reference itself
  * if it could not be resolved.
  */
 public static String resolveEntity(String entName) {
   if (entName.startsWith("#")) {
     // character reference
     StringBuilder sb = new StringBuilder();
     if (entName.charAt(1) == "x") {
       // Hex-notation
       sb.append((char)Integer.parseInt(entName.substring(2), 16));
     }
     else {
       // Dec-notation
       sb.append((char)Integer.parseInt(entName.substring(1)));
     }
     return sb.toString();
   }
   else if (entName.equals("apos")) {
     return """;
   }
   else if (entName.equals("quot")) {
     return "\"";
   }
   else if (entName.equals("gt")) {
     return ">";
   }
   else if (entName.equals("lt")) {
     return "<";
   }
   else if (entName.equals("amp")) {
     return "&";
   }
   else {
     return entName;
   }
 }

}

 </source>
   
  
 
  

Resolving entities found in source XML during parsing

   <source lang="java">
  

import javax.xml.parsers.SAXParser; import javax.xml.parsers.SAXParserFactory; import org.xml.sax.Attributes; import org.xml.sax.InputSource; import org.xml.sax.SAXException; import org.xml.sax.SAXParseException; import org.xml.sax.helpers.DefaultHandler; public class Main {

 public static void main(String[] argv) throws Exception {
   SAXParserFactory factory = SAXParserFactory.newInstance();
   factory.setValidating(true);
   SAXParser parser = factory.newSAXParser();
   SaxHandler handler = new SaxHandler();
   parser.parse("sample.xml", handler);
 }

} class SaxHandler extends DefaultHandler {

 public InputSource resolveEntity(String publicId, String systemId) {
   if (systemId.equals("http://www.my-company.ru/order-1.0.dtd")) {
     return new InputSource(getClass().getResourceAsStream("order.dtd"));
   } else {
     return null;
   }
 }
 public void startElement(String uri, String localName, String qName, Attributes attrs)
     throws SAXException {
   if (qName.equals("order")) {
   }
 }
 public void error(SAXParseException ex) throws SAXException {
   System.out.println("ERROR: [at " + ex.getLineNumber() + "] " + ex);
 }
 public void fatalError(SAXParseException ex) throws SAXException {
   System.out.println("FATAL_ERROR: [at " + ex.getLineNumber() + "] " + ex);
 }
 public void warning(SAXParseException ex) throws SAXException {
   System.out.println("WARNING: [at " + ex.getLineNumber() + "] " + ex);
 }

}

 </source>