dom4j生成xml时添加standalone属性

public class StandaloneWriter extends XMLWriter {



protected void writeDeclaration() throws IOException {

  OutputFormat format = getOutputFormat();



  String encoding = format.getEncoding();



  if (!format.isSuppressDeclaration()) {

    if (encoding.equals("UTF8")) {

      writer.write("<?xml version=\"1.0\"");



      if (!format.isOmitEncoding()) {

        writer.write(" encoding=\"UTF-8\"");

      }



      writer.write(" standalone=\"true\"");

      writer.write("?>");

    } else {

      writer.write("<?xml version=\"1.0\"");



      if (!format.isOmitEncoding()) {

        writer.write(" encoding=\"" + encoding + "\"");

      }



      writer.write(" standalone=\"true\"");

      writer.write("?>");

    }



    if (format.isNewLineAfterDeclaration()) {

      println();

    }

  }

}