commons-upload如何上传到目录？

请问怎样用COMMONS-UPLOAD编写SERLVET 上传文件到WEB 服务器的目录呢~？
像以下的这样，如何做到上传到WEB 服务器的根目录呢
javax.servlet.http.HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
 */
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
}  

/* (non-Java-doc)
 * @see javax.servlet.http.HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
 */
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
try{
request.setCharacterEncoding("gb2312");
String path=request.getContextPath();
if(ServletFileUpload.isMultipartContent(request)){
ServletFileUpload upload=new ServletFileUpload();
FileItemIterator iter=upload.getItemIterator(request);

while(iter.hasNext()){
FileItemStream item=iter.next();
String name=item.getFieldName();
InputStream stream=item.openStream();
if(item.isFormField()){
response.getWriter().print("File filed");
}else
{
String filename=new File(item.getName()).getName();
response.getWriter().print("File filed:"+filename);
BufferedInputStream bis=new BufferedInputStream(stream);
BufferedOutputStream bos=new BufferedOutputStream(new FileOutputStream(new File("\\upload\\"+filename)));
Streams.copy(bis, bos, true);


}
}
}



}catch(Exception e){
response.getWriter().print(e.toString());

}

}           
}