我正在尝试通过以下方式在我正在构建的xml中强制执行编码:XmlWriterSettingsxmlSetting=newXmlWriterSettings();XmlWriterxmlWriter;Strres;xmlSetting.encoding('UTF-8');xmlWriter=XmlWriter::newXml(xmlSetting);xmlWriter.writeStartDocument();xmlWriter.writeStartElement('root');xmlWriter.writeEndElement();xmlWriter.writeEndDocument