@RequestMapping(method=RequestMethod.POST,value = "http://www.mamicode.com/upload")       public ModelAndView processImageUpload(@RequestParam(value="http://www.mamicode.com/groupname",required=false) String group,            @RequestParam(value="remotefilename",required=false) String remotefilename,            @RequestParam(value="extname",required=true) String extname,            @RequestParam("file") MultipartFile file ,@RequestParam(value="http://www.mamicode.com/format",required=false) String format   // 关键就是这句话起了作用                ){        Response<FastDFSFile> response  = new Response<FastDFSFile>();        ReturnResult<FastDFSFile> returnResult = new ReturnResult<FastDFSFile>();        ResponseHeader responseHeader = new ResponseHeader();        boolean appendFlag = false;        String[] results = null;        try {            if (!file.isEmpty()) {                if(group != null && !group.equals("") && remotefilename != null && !remotefilename.equals("")){                    results = new String[2];                    results[0] = group;                    results[1] = remotefilename;                    appendFlag = true;                }else                    appendFlag = false;                byte[] file_buff = file.getBytes();                                String[] fDinfo = FastDFS.getServer().upload(appendFlag, results, file_buff, extname);                if(fDinfo.length == 2){                    List<FastDFSFile> fileList = new ArrayList<FastDFSFile>();                    FastDFSFile info = new FastDFSFile();                    info.setGroupname(fDinfo[0]);                    info.setRemotefilename(fDinfo[1]);                    fileList.add(info);                    responseHeader.setStatus(0);                    returnResult.setNumFound(1);                    returnResult.setStart(1);                    returnResult.setFilelist(fileList);                }else if(fDinfo.length == 1){                    throw new UFEException(fDinfo[0]);                }else{                    throw new UFEException("no return fastDFS!");                }              }else{                  RError er = new RError();                  er.setInfo("No file!");                  er.setType(1);                  responseHeader.setError(er);                  responseHeader.setStatus(1);              }        } catch (Exception e1) {            RError er = new RError();            if(e1.getCause() == null)                er.setInfo(e1.getMessage());            else                er.setInfo(e1.getCause().getMessage());            er.setType(1);            responseHeader.setStatus(1);            responseHeader.setError(er);        }        response.setResult(returnResult);        response.setResponseHeader(responseHeader);        if(format != null && format.equals("json"))             return new ModelAndView(TypeDef.JSON_VIEW_NAME, "object", response);        else             return new ModelAndView(TypeDef.XML_VIEW_NAME, "object", response);    }