如何格式化XML xml格式化输出

import org.apache.xml.serialize.OutputFormat;import org.apache.xml.serialize.OutputFormat;import org.apache.xml.serialize.XMLSerializer;import org.w3c.dom.Document;import org.xml.sax.InputSource;import org.xml.sax.SAXException;import javax.xml.parsers.DocumentBuilder;import javax.xml.parsers.DocumentBuilderFactory;import javax.xml.parsers.ParserConfigurationException;import java.io.IOException;import java.io.StringReader;import java.io.StringWriter;import java.io.Writer;/** * Created by IntelliJ IDEA. * User: tsaowe * Date: 11-9-1 * Time: 上午9:13 */public class XmlFormatter {    public String format(String unformattedXml) {        try {            final Document document = parseXmlFile(unformattedXml);            OutputFormat format = new OutputFormat(document);            format.setLineWidth(65);            format.setIndenting(true);            format.setIndent(2);            Writer out = new StringWriter();            XMLSerializer serializer = new XMLSerializer(out, format);            serializer.serialize(document);            return out.toString();        } catch (IOException e) {            throw new RuntimeException(e);        }    }    private Document parseXmlFile(String in) {        try {            DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();            DocumentBuilder db = dbf.newDocumentBuilder();            InputSource is = new InputSource(new StringReader(in));            return db.parse(is);        } catch (ParserConfigurationException e) {            throw new RuntimeException(e);        } catch (SAXException e) {            throw new RuntimeException(e);        } catch (IOException e) {            throw new RuntimeException(e);        }    }    public static void main(String[] args) throws Exception{        String s = "<?xml version="1.0" encoding="UTF-8"?><PARAM><DBID>35</DBID><SEQUENCE>atgtca</SEQUENCE><MAXNS>10</MAXNS><MINIDENTITIES>90</MINIDENTITIES><MAXEVALUE>10</MAXEVALUE><USERNAME>admin</USERNAME><PASSWORD>111111</PASSWORD><TYPE>P</TYPE><RETURN_TYPE>2</RETURN_TYPE></PARAM>";//未格式化前的xml        System.out.println(new XmlFormatter().format(s));            }}

<?xml version="1.0" encoding="UTF-8"?><PARAM>  <DBID>35</DBID>  <SEQUENCE>atgtca</SEQUENCE>  <MAXNS>10</MAXNS>  <MINIDENTITIES>90</MINIDENTITIES>  <MAXEVALUE>10</MAXEVALUE>  <USERNAME>admin</USERNAME>  <PASSWORD>111111</PASSWORD>  <TYPE>P</TYPE>  <RETURN_TYPE>2</RETURN_TYPE></PARAM>