一、使用最原始的javax.xml.parsers，标准的jdk api 
// 字符串转XML
String xmlStr = "......";
StringReader sr = new StringReader(xmlStr);
 InputSource is = new InputSource(sr); 
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); 
DocumentBuilder builder=factory.newDocumentBuilder();
Document doc = builder.parse(is); 
//XML转字符串
TransformerFactory  tf  = TransformerFactory.newInstance();Transformer t =tf.newTransformer();t.setOutputProperty("encoding","GB23121");//解决中文问题，试过用GBK不行
ByteArrayOutputStream  bos  = new ByteArrayOutputStream();t.transform(new DOMSource(doc), new StreamResult(bos));
String xmlStr = bos.toString(); 
这里的XML DOCUMENT为org.w3c.dom.Document 
二、使用dom4j后程序变得更简单 
// 字符串转
XMLString xmlStr = "......";
Document document = DocumentHelper.parseText(xmlStr); 
// XML转字符串
Document document = ...;
String text = document.asXML(); 
这里的XML DOCUMENT为org.dom4j.Document 
三、使用JDOM 
JDOM的处理方式和第一种方法处理非常类似 
//字符串转XML
String xmlStr = ".....";
StringReader sr = new StringReader(xmlStr);
InputSource is = new InputSource(sr);
Document doc = (new SAXBuilder()).build(is); 
//XML转字符串
Format format =Format.getPrettyFormat();format.setEncoding("gb2312");//设置xml文件的字符为gb2312，解决中文问题
XMLOutputter xmlout =new XMLOutputter(format);
ByteArrayOutputStream bo = new ByteArrayOutputStream();
xmlout.output(doc,bo);
String xmlStr = bo.toString(); 
这里的XML DOCUMENT为org.jdom.Document 
四、JAVASCRIPT中的处理 
//字符串转XML
var xmlStr = ".....";
var xmlDoc = new ActiveXObject("Microsoft.XMLDOM");
xmlDoc.async=false;xmlDoc.loadXML(xmlStr);//可以处理这个xmlDoc了
var name = xmlDoc.selectSingleNode("/person/name");
alert(name.text); 
//XML转字符串
var xmlDoc = ......;
var xmlStr = xmlDoc.xml 
这里的XML DOCUMENT为javascript版的XMLDOM 
转自：http://blog.csdn.net/yhl_621/article/details/614960