servlet中out.println（）的xml无法在ajax获取到

out.println("");
out.println("");
for(int i=0;ixxinfo xx=(xxinfo)Al.get(i);
String stuname=xx.getName();
out.println(""+stuname+"");
}
out.println(""+"1213"+"");
out.println("");
------------------servlet中的输出----------------------
xmlHttp.onreadystatechange=function(){
if(xmlHttp.readyState==4){
var xmlDom=xmlHttp.responseXml;
var xxinfos=xmlDom.getElementsByTagName("stun");
alert(xxinfos.length);
---------------------此处alert的输出为0----------------------

你输出的只不过是一堆类似xml文件的一些字符串而已，并不是xml数据。
LOG.info("******dom4j start create xml document stream*******");
Document doc = DocumentHelper.createDocument();
Element rootElement = doc.addElement("students");
Element pageElement = rootElement.addElement("page");

pageElement.setText(isreset);
rootElement.addComment("all students is here!");
if(stus != null && !stus.isEmpty()){
LOG.info("*******students number:" + stus.size() + "**********");
for(int i=0;i Element studentElement = rootElement.addElement("student");
Element id = studentElement.addElement("id");
Element name = studentElement.addElement("name");
Element age = studentElement.addElement("age");
Element sex = studentElement.addElement("sex");
Element country = studentElement.addElement("country");
id.setText(stus.get(i).getId() + "");
name.setText(stus.get(i).getName());
age.setText(stus.get(i).getAge() + "");
String sexName = stus.get(i).getSex()；
sex.setText(sexName);
country.setText(stus.get(i).getCountry());
}
LOG.info("******dom4j success create xml document*******");
}else{
LOG.info("******get no student*******");
}
resp.setContentType("text/xml;charset=utf-8");
resp.setHeader("pragma","no-cache");
resp.setHeader("cache-control","no-cache");
PrintWriter out = resp.getWriter();
OutputFormat format = OutputFormat.createPrettyPrint();
format.setEncoding("utf-8");
XMLWriter xmlWriter = new XMLWriter(out,format);
xmlWriter.write(doc);
out.flush();
out.close();

ajax异步操作如果有返回值的话，需要在回调函数中对返回值作相应处理，才会有结果，上面这段代码比较合适的写法是这样（在room.jsp中用jquery）： room.jsp中： $.get("你的servlet",{},function(result){ alert(result); }) 其中：function(result){}就是回调函数 servlet中 out.print( “站起来");