public class FileDemo {
 public static void main(String[] args) {
  
 File f=new File("d:"+File.separator+"io.txt");
 //File.separator 得到“\”
 //File.pathSeparator得到是“;”
 try {
  f.createNewFile();
 } catch (IOException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
 }
 //等等一段時間，可以查看文件的生成
 try {
  Thread.sleep(3000);
 } catch (InterruptedException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
 }
 if(f.exists()){
  f.delete();
 }else{
  System.out.println("文件不存在");
 }
 }
}

 public void fileUpload(@RequestParam MultipartFile[] myfiles,
 
  HttpServletRequest request, HttpServletResponse response)
 
  throws IOException {
 
 String imgPath = "/uploads" + "/";
 
 File directory = new File(request.getSession().getServletContext()
 
  .getRealPath("/")
 
  + imgPath);
 
 String desFileName = null;
 
 String fileNewName = null;
 
 response.setContentType("text/html; charset=UTF-8");
 
 PrintWriter out = response.getWriter();
 
 String originalFilename = null;
 
 for (MultipartFile myfile : myfiles) {
 
  if (myfile.isEmpty()) {
 
  out.write("請選擇文件后上傳");
 
  out.flush();
 
  } else {
 
  originalFilename = myfile.getOriginalFilename();
 
  if (null != originalFilename && originalFilename.length() > 0) {
 
   fileNewName = UUID.randomUUID() + originalFilename;
 
   desFileName = directory.toString() + "/" + fileNewName;
 
  }
 
  try {
 
   FileUtils.copyInputStreamToFile(myfile.getInputStream(),
 
    new File(desFileName));
 
  } catch (IOException e) {
 
   e.printStackTrace();
 
   out.write("文件上傳失敗，請重試??！");
 
   out.flush();
 
  }
 
  }
 
 }
 
 out.print(fileNewName);
 
 out.flush();
 
 }

 File f1=new File("d:"+File.separator+"test");
 
 f1.mkdir();
 
 //獲取文件夾名稱的方法
 f1.getName();