@Override
  protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    req.setCharacterEncoding("utf-8");
    resp.setContentType("text/html;charset=utf-8");
    //服務(wù)器存儲文件的地址，需自己定義
    String savepath = this.getServletContext().getRealPath("/upload");
    System.out.println(savepath);
    //如果文件不存在，需要先進(jìn)行判斷，并創(chuàng)建，否則會出現(xiàn)空文件報錯
    File file=new File(savepath);
    if(!file.exists()){
      file.mkdir();
    }
    //工具類commons-fileupload包創(chuàng)建工廠對象
    DiskFileItemFactory itemFactory=new DiskFileItemFactory();
    ServletFileUpload  upload=new ServletFileUpload(itemFactory);
    //判斷是不是傳統(tǒng)表單
    if(!ServletFileUpload.isMultipartContent(req)){
      System.out.println("是傳統(tǒng)的表單 沒有上傳功能");
      return;
    }

    try {
      //表單的各項數(shù)據(jù)對象，封裝成集合
      List<FileItem> list = upload.parseRequest(req);
      for(FileItem item:list){

        //是普通的表單數(shù)據(jù)
        if(item.isFormField()){
          String fieldName = item.getFieldName();
          String value = item.getString("utf-8");
          System.out.println(fieldName+"  "+value);
        }else {
          String filename = item.getName();//上傳的文件名字
          if(filename==null||filename.trim().equals("")){
            // 當(dāng)前上傳的文件為空
            continue;
          }
          System.out.println(filename);
          //得到文件的名字
          filename = filename.substring(filename.lastIndexOf("\\")+1);

          InputStream in = item.getInputStream();

          OutputStream out=new FileOutputStream(savepath+"\\"+filename);

          byte[] buf=new byte[1024];
          int len=0;
          while((len=in.read(buf))>0){
            out.write(buf,0,len);
          }
          in.close();
          out.close();
        }

      }
    } catch (FileUploadException e) {
      e.printStackTrace();
    }

  req.getRequestDispatcher("/downloadlist").forward(req,resp);
  }

@Override
  protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    req.setCharacterEncoding("utf-8");
    resp.setContentType("text/html;charset=utf-8");
    //獲取前臺文件所展示的文件名稱和存儲目錄下的名稱要一致，方便寫參數(shù)下載。
    String fileName= req.getParameter("file");

    //先獲取上傳目錄路徑
    String basePath = getServletContext().getRealPath("/upload");

    //如果文件名是中文,需要進(jìn)行url編碼，此操作是為了避免不同瀏覽器的下載頁面下文件亂碼的情況
    String agent = req.getHeader("User-Agent");
    String filenameEncoder = "";
    if (agent.contains("MSIE")) {
      // IE瀏覽器
      filenameEncoder = URLEncoder.encode(fileName, "utf-8");
      filenameEncoder = filenameEncoder.replace("+", " ");
    } else if (agent.contains("Firefox")) {
      // 火狐瀏覽器
      BASE64Encoder base64Encoder = new BASE64Encoder();
      filenameEncoder = "=?utf-8?B?"
          + base64Encoder.encode(fileName.getBytes("utf-8")) + "?=";
    } else {
      // 其它瀏覽器
      filenameEncoder = URLEncoder.encode(fileName, "utf-8");
    }


    //設(shè)置下載的響應(yīng)頭
    resp.setHeader("content-disposition", "attachment;fileName="+filenameEncoder);//此filenameEncoder必須經(jīng)過轉(zhuǎn)碼處理
    //獲取一個文件輸入流
    InputStream is = new FileInputStream(new File(basePath,fileName));
    //獲取response字節(jié)流
    OutputStream out = resp.getOutputStream();
    byte[] b= new byte[1024];
    int len =-1;
    while((len=is.read(b))!=-1){
      out.write(b,0,len);
    }
    //關(guān)閉流
    out.close();
    is.close();
  }

@RequestMapping("/upload")
  public String upload(MultipartFile file,String userName,HttpServletRequest request) throws IOException {
    String filename = file.getOriginalFilename();

    String suffix = filename.substring(filename.lastIndexOf("."));

    if(suffix.equalsIgnoreCase(".jpg")){
      String uuid = UUID.randomUUID().toString();
      //FileUtils.copyInputStreamToFile(file.getInputStream(),new File("E://"+uuid+suffix));

      file.transferTo(new File("D://"+System.currentTimeMillis()+suffix));//位置存儲在硬盤上
//      file.transferTo(new File(request.getServletContext().getRealPath("/")+"static/userImages/"+file));
//      存儲在項目里的目錄下
      request.setAttribute("result","上傳成功");
      return "/result.jsp";
    }else{
      request.setAttribute("result","上傳失敗");
      return "/result.jsp";
    }
  }

@RequestMapping("/download")
  public void download(String filename, HttpServletResponse response, HttpServletRequest request) throws IOException {
    response.setHeader("content-disposition","attachment;filename="+filename);

    ServletOutputStream outputStream = response.getOutputStream();

    String path = request.getServletContext().getRealPath("images");

    File file = new File(path,filename);

    byte[] bytes = FileUtils.readFileToByteArray(file);

    outputStream.write(bytes);

    outputStream.close();
  }