Question

I’m writing a applet that uses a DTD file to check the content of the XML it receives.

I had the problem of the DTD not placed in the right folder with the applet viewer, but now that I’m testing this on the server I get the same error again.

java.security.AccessControlException: 
    access denied (java.io.FilePermission/leveldtd.dtd read)

How can I fix this when the applet is on the server?

---

public static void parseThis(InputSource is) throws Exception{
        SAXParserFactory spf = SAXParserFactory.newInstance();
        SAXParser sp = spf.newSAXParser();
        XMLHandlerLevel myExampleHandler = new XMLHandlerLevel();
        XMLReader xr = sp.getXMLReader();
        xr.setContentHandler(myExampleHandler);
        /* Begin parsing */ 
        xr.parse(is);
    }

XML parser creation.

Answer 1

For an applet to get a resource from a server, it must use an URL. File objects will not work because:

1. The File object will point to a place on the computer of the user.
2. It requires a trusted applet to use File objects. Hence the AccessControlException in your output.

URLs to resources can easily be formed using the URL(baseURL, pathString) constructor where the base URL is obtained from Applet.getDocumentBase() or Applet.getCodeBase().

..how do I give the URL to the parser ?

Here is a code snippet taken from JaNeLA that uses an XSD located inside one of the Jars. The URL is stored in schemaSource.

try {
    URL schemaSource = Thread.currentThread().getContextClassLoader().getResource("JNLP-6.0.xsd");
    System.out.println( "schemaSource: " + schemaSource );

    DocumentBuilderFactory factory =
        DocumentBuilderFactory.newInstance();
    factory.setFeature("http://xml.org/sax/features/validation", true);
    factory.setFeature("http://apache.org/xml/features/validation/schema", true) ;
    factory.setFeature("http://xml.org/sax/features/namespaces", true) ;
    factory.setFeature("http://apache.org/xml/features/validation/schema-full-checking", true);
    factory.setAttribute(
        "http://apache.org/xml/properties/schema/external-noNamespaceSchemaLocation",
        schemaSource.toString());
    factory.setNamespaceAware(true);
    factory.setValidating(true);

    InputStream schemaStream = schemaSource.openStream();
    try {
        StreamSource ss = new StreamSource( schemaStream );
        String language = XMLConstants.W3C_XML_SCHEMA_NS_URI;
        SchemaFactory schemaFactory = SchemaFactory.newInstance(language);

        Schema schema = schemaFactory.newSchema(ss);
        factory.setSchema( schema );
    }
    finally {
        schemaStream.close();
    }

    DocumentBuilder documentBuilder = factory.newDocumentBuilder();
    documentBuilder.setErrorHandler( errorHandler );

    InputStream is = page.openStream();
    try {
        document = documentBuilder.parse( is );
    }
    finally {
        is.close();
    }

    List<LaunchError> parseErrors = errorHandler.getParseErrors();
    xmlValid = parseErrors.isEmpty();
    errors.addAll(parseErrors);
} catch(Exception e) {
    System.err.println( "Error: " + e.getMessage() );
    // TODO Show to user
}