文件上传，查看 思路



 public static String uploadHead(HttpServletRequest request,FormFile ff,String id){
 
  String newPhotoName="";
  try{
  //考虑给每个用户创建自己的文件夹.
  String filePath=request.getSession().getServletContext().getRealPath("/");
  //filePath就是当前这个web应用是绝对路径 F:\apache-tomcat-6.0.20\webapps\xiaoneinew
  InputStream stream = ff.getInputStream();// 把文件读入
  String oldPhotoName=ff.getFileName();
  newPhotoName=id+oldPhotoName.substring(oldPhotoName.indexOf("."), oldPhotoName.length());
  String newFullNewPath=filePath+"\\images\\"+id+"\\head\\";
  //判断newFullNewPath文件夹是否存在
  File f=new File(newFullNewPath);
  if(!f.isDirectory()){
   //不是文件夹,创建即可
   f.mkdirs();
   
  }
  //把上传的头像名字修成成 编号.后缀
  
  OutputStream bos = new FileOutputStream(newFullNewPath+ newPhotoName);
  int len = 0;
  byte[] buffer = new byte[8192];
  while ((len = stream.read(buffer, 0, 8192)) != -1) {
   bos.write(buffer, 0, len);// 将文件写入服务器
  }
  bos.close();
  stream.close();

 } catch (Exception e) {
  e.printStackTrace();
 }
 return newPhotoName;
 }