When I Use Xercerse package to parse a xml document which contains <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.0//EN" "http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd">. Because my computer is not connected to Internet, so "www.w3.org not found" exception is thrown. How to solve the problem?

Hi,
  You need to use the EntityResolver in order to resolve this to a copy of the DTD on your local file system.
org.xml.sax.EntityResolver.
 Below is the code required for you.....

import javax.xml.parsers.*;
import org.xml.sax.*;

....
....
SAXParser saxParser = SAXParserFactory.newInstance().newSAXParser();
XMLReader xmlReader = saxParser.getXMLReader();
MyResolver myResolver = new MyResolver();
xmlReader.setEntityResolver(myResolver);
...
xmlReader.parse(..);

your class should be,
 import org.xml.sax.EntityResolver;
 import org.xml.sax.InputSource;

 public class MyResolver implements EntityResolver {
   public InputSource resolveEntity (String publicId, String systemId)
   {
     if (systemId.equals("http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd")
             || publicId.equals("-//W3C//DTD SVG 1.0//EN")) {
           // return a special input source
           FileReader fileReader = new FileReader("/usr/home/work/dtds/svg10.dtd");
           return new InputSource(fileReader);
     } else {
              // use the default behaviour
       return null;
     }
   }
 }


Hope it helps you...
regards,
Gopi