xml 里面有没有什么API供xml文件的输出啊？

Question

package au.edu.qut.yawl.unmarshal;/**
 * <p>Title: Pretty XML</p>
 *
 * <p>Description: Pretty XML</p>
 *
 * <p>Copyright: Copyright (c) 2004</p>
 *
 * <p>Company: </p>
 *
 * @author YuLimin
 * @version 1.0
 */
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.OutputStream;import org.jdom.Document;
import org.jdom.Element;
import org.jdom.input.SAXBuilder;
import org.jdom.output.Format;
import org.jdom.output.XMLOutputter;public class PrettyXML
{
    private String extName = "";    public PrettyXML()
    {
    }    public String getExtName()
    {
        return extName;
    }    public void pretty(String filename)
    {
    }    public void pretty(String filename,String strTemp)
    {
        try
        {
            // Build the document with SAX and Xerces, no validation
            SAXBuilder builder = new SAXBuilder();            // Create the document
            Document doc = builder.build(new File(filename));            // Output the document, use Pretty formatter
            XMLOutputter fmt = new XMLOutputter();
            fmt.setFormat(Format.getPrettyFormat());
            fmt.setFormat(Format.getPrettyFormat().setEncoding("GB2312"));            //FileOutputStream
            OutputStream os = new FileOutputStream(filename + extName);
            fmt.output(doc,os);
            os.flush();
            os.close();
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }
    }    public void setExtName(String ExtName)
    {
        this.extName = ExtName;
    }    /**
     *  这个方法将JDom对象转换字符串.
     *  @param  document  将要被转换的JDom对象
     *  @param  encoding  输出字符串使用的编码
     *  @return  String  xml对象保存到的字符串
     */
    public static String OutputToString(Document document,String encoding)
    {
        ByteArrayOutputStream byteRep = new ByteArrayOutputStream();
        XMLOutputter docWriter = new XMLOutputter(); //"        ",true,encoding);        try
        {
            docWriter.output(document,byteRep);
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }        return byteRep.toString();
    }    public static void main(String[] args)
    {
        String filenameIn = ""; //args[0];
        filenameIn = "F:\\Java\\YAWL\\取水许可申请审批New.xml";        PrettyXML prettyXML = new PrettyXML();
        prettyXML.setExtName("Pretty.xml");
        prettyXML.pretty(filenameIn);        try
        {
            // Build the document with SAX and Xerces, no validation
            SAXBuilder builder = new SAXBuilder();
            // Create the document
            Document doc = builder.build(new File(filenameIn));
//            doc =builder.build(new java.io.BufferedReader("a"));
            prettyXML.accessChildElement(doc);
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }
    }    public static void accessChildElement(Document myDocument)
    {
        Element root = myDocument.getRootElement();
        System.out.println(root.getName());
        System.out.println(root.getText());        Element child = root.getChild("specification"); //.getChild("specification").getChild("name");
        java.util.List lst = root.getChildren();
        for(int i = 0;i < lst.size();i++)
        {
            System.out.println(i + ":" + ((Element)lst.get(i)).getName());
        }
        if(child != null)
        {
            System.out.println("Here is the element we found: " + child.getName() + ".  Its content: " + child.getText() + "\n");
        }
        else
        {
            System.out.println("Something is wrong.  We did not find a year Element");
        }
    }
}