import com.sun.org.apache.xerces.internal.parsers.XMLGrammarPreparser; //导入依赖的package包/类
public static void main(String[] args) throws FileNotFoundException, XNIException, IOException {
    File xsdf = new File(System.getProperty("test.src", ".") + "/test.xsd");
    InputStream is = new BufferedInputStream(new FileInputStream(xsdf));
    XMLInputSource xis = new XMLInputSource(null, null, null, is, null);
    XMLGrammarPreparser gp = new XMLGrammarPreparser();
    gp.registerPreparser(XMLGrammarDescription.XML_SCHEMA, null);
    //The NullPointerException is observed on next call during ant task
    // execution
    Grammar res = gp.preparseGrammar(XMLGrammarDescription.XML_SCHEMA, xis);
    System.out.println("Grammar preparsed successfully:" + res);
    return;
}