Spring MVC上传、下载 文件

1，上传文件

 public static String upload(MultipartFile file, SysUserBean sysUserBean, HttpServletRequest request){
         SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd");
          Date date = new Date();
         String path = request.getSession().getServletContext().getRealPath("upload\\"+sysUserBean.getId()+"\\"+sdf.format(date));
         String fileLastName = "";
         String fileName = "";
         if(file != null){
             int dot = file.getOriginalFilename().lastIndexOf('.');
             if(dot>0){
                 fileLastName = file.getOriginalFilename().substring(dot);
                 fileName = UUID.randomUUID()+fileLastName;
                 File targetFile = new File(path, fileName);
                 if(!targetFile.exists()){
                     targetFile.mkdirs();
                 }
                 try {
                     file.transferTo(targetFile);
                 } catch (Exception e) {
                     e.printStackTrace();
                     return "";
                 }
                 return "upload/"+sysUserBean.getId()+"/"+sdf.format(date)+"/"+fileName;
             }else{
                 return "";
             }
         }
         return "";
     }

2，下载文件

 public static void download(String fileName, HttpServletRequest request,
                 HttpServletResponse response)throws Exception {
             response.setContentType("text/html;charset=utf-8");
             request.setCharacterEncoding("UTF-8");
             java.io.BufferedInputStream bis = null;
             java.io.BufferedOutputStream bos = null;   

             String path = request.getSession().getServletContext().getRealPath("\\");
             String downLoadPath = path + fileName;
             System.out.println(downLoadPath);
             try {
                 long fileLength = new File(downLoadPath).length();
                 response.setContentType("application/x-msdownload;");
                 response.setHeader("Content-disposition", "attachment; filename="
                         + new String(fileName.getBytes("utf-8"), "ISO8859-1"));
                 response.setHeader("Content-Length", String.valueOf(fileLength));
                 bis = new BufferedInputStream(new FileInputStream(downLoadPath));
                 bos = new BufferedOutputStream(response.getOutputStream());
                 byte[] buff = new byte[2048];
                 int bytesRead;
                 while (-1 != (bytesRead = bis.read(buff, 0, buff.length))) {
                     bos.write(buff, 0, bytesRead);
                 }
             } catch (Exception e) {
                 e.printStackTrace();
             } finally {
                 if (bis != null)
                     bis.close();
                 if (bos != null)
                     bos.close();
             }                   }   

3，base64 转成图片

 // 对字节数组字符串进行Base64解码并生成图片
 public static String GenerateImage(String imgStr,HttpServletRequest request,String userid) {
         SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd");
          Date date = new Date();
         if (imgStr == null) // 图像数据为空
             return "";
         UUID uuid = UUID.randomUUID();
         String fileName = uuid+".jpg";
         String path = request.getSession().getServletContext().getRealPath("upload\\"+userid+"\\"+sdf.format(date));
         File targetFile = new File(path);
         path = path+"\\"+fileName;
         System.out.println(path);
         if(!targetFile.exists()){
             targetFile.mkdirs();
         }
         BASE64Decoder decoder = new BASE64Decoder();
         try {
             // Base64解码
             byte[] bytes = decoder.decodeBuffer(imgStr);
             for (int i = 0; i < bytes.length; ++i) {
                 if (bytes[i] < 0) {// 调整异常数据
                     bytes[i] += 256;
                 }
             }
             // 生成jpeg图片
             OutputStream out = new FileOutputStream(path);
             out.write(bytes);
             out.flush();
             out.close();
             return "upload/"+userid+"/"+sdf.format(date)+"/"+fileName;
         } catch (Exception e) {
             e.printStackTrace();
             return "";
         }
     }