有谁知道如何使用Java的XMLStreamWriter正确输出扩展字符(非BMP，多于1个char)？例如，尝试输出UnicodeU+10480?:importjava.io.OutputStreamWriter;importjava.nio.charset.StandardCharsets;importjavax.xml.stream.XMLOutputFactory;importjavax.xml.stream.XMLStreamException;importjavax.xml.stream.XMLStreamWriter;publicclassXmlStreamWriterE