java解析xml禁止校验dtd

builder.setEntityResolver(
                new EntityResolver(){
                   public InputSource resolveEntity(String publicId, String systemId) throws SAXException, IOException
                   {
                       return new InputSource(new StringBufferInputStream(""));   
//                       return null;//这个的效果仍然是从网络来抓取DTD来验证
                       }
                }
            );