文件流上传，下载

更新的时候要将更新的model放到for循环里面new，否则上传多个文件时只会更新最后一条

/*** 上传项目附件并更新附件表(多文件,之间用&隔开) * @return fileName 文件名 * @return fileType 文件类型 * @return projectId 项目编号 */public Map<String, Object> prjUpload(HttpServletRequest request, String fileName, String projectId, boolean isUnique) throws IllegalStateException, IOException {           Map<String, Object> map = new HashMap<>();    PrjInfo prjInfo = new PrjInfo();            prjInfo = getPrjInfoByProjectId(projectId);    String projectName = prjInfo.getProjectName();    String[] fileNameArray = fileName.split("&");           //是否一个文件名对应一个文件类型    if(StringUtil.isEmpty(String.valueOf(fileNameArray))){        map.put("code", 418);        map.put("msg", "传入文件错误,请重新上传");        return map;                 }else{        String filePath = "project-"+projectId;        //Map<String, Object> uploadResults = uploadListFiles(request, filePath, true);        //创建一个通用的多部分解析器          CommonsMultipartResolver multipartResolver = new CommonsMultipartResolver(request.getSession().getServletContext());        //判断 request 是否有文件上传,即多部分请求          StringBuffer buffer = new StringBuffer();        String localFileUrl="";        if (multipartResolver.isMultipart(request))        {            //转换成多部分request                MultipartHttpServletRequest multiRequest = (MultipartHttpServletRequest) request;            //取得request中的所有文件名  ***"files"为前台inpu框的name值***            List<MultipartFile> files = multiRequest.getFiles("files");            //MultipartFile类型的变量file在files集合范围内循环            for(MultipartFile  file:files){                if (file != null)                {                    //取得当前上传文件的文件名称                      String myFileName = file.getOriginalFilename();                    //如果名称不为"",说明该文件存在，否则说明该文件不存在                      if (myFileName.trim() != ""){                        //重命名上传后的文件名                          String renameFileName = file.getOriginalFilename();                        String absPath = WebConstants.SERVER_FILE_ESCAPE_PATH + filePath;                        new File(absPath).mkdirs();                        String path = absPath + File.separator + renameFileName;                        if(isUnique){                            String name = path.substring(0, path.lastIndexOf("."));                            String suffix = path.substring(path.lastIndexOf("."), path.length());                            path = name + suffix;                        }                        File localFile = new File(path);                        file.transferTo(localFile);                        localFileUrl=localFile.toString();                        buffer.append(localFileUrl).append("&");                    }                                   }             }        }        String localFileUrls = buffer.toString();        if (localFileUrls.endsWith("&")){            localFileUrls = localFileUrls.substring(0, localFileUrls.length() - 1);        }                               for(int i=0; i < fileNameArray.length; i++){            PrjProgramUrl prjProgramUrl = new PrjProgramUrl();            String[] localFileUrlStrArray = localFileUrls.split("&");            Date createDate = DateUtil.getCurrentDate();            Integer createuserId = HttpUtils.getCurrentUser().getId();            String programId = projectId+"-" + fileNameArray[i];            String url = localFileUrlStrArray[i];            if (!StringUtil.isEmpty(url) && !StringUtil.isEmpty(fileNameArray[i])){                prjProgramUrl.setCreateDate(createDate);                prjProgramUrl.setCreateuserId(createuserId);                prjProgramUrl.setProgramId(programId);                prjProgramUrl.setUrl(url);                prjProgramUrlService.add(prjProgramUrl);            }         }        map.put("code", 200);        map.put("msg", "上传成功");        map.put("prjProgramUrl", null);        return map;    }}

下载的时候不能用ajax下载，因为下载的文件会存到js的内存中，success 的data里面。但是不会下载，可以用window.open(url);

/** * 文件的下载 *  * @param response *            响应流 * @param filePath *            文件的全路径 * @param fileName *            输出流的文件名称 * @throws Exception */public static void downloadFile(HttpServletResponse response, String filePath, String fileName) throws Exception {    File file = new File(filePath);    long fileLength = file.length();    response.setCharacterEncoding("utf-8");    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));    InputStream inputStream = new FileInputStream(file);    OutputStream os = response.getOutputStream();    byte[] b = new byte[1024];    int length;    while ((length = inputStream.read(b)) > 0)    {        os.write(b, 0, length);    }    inputStream.close();}