springMVC上傳文件優化

1.spring通過對Servlet Api的HttpServletRequest接口進行擴展，使其能夠很好地處理文件上傳，擴展後的接口名爲
MultipartHttpServletRequest
對大文件類型處理效果較好，開發中使用這種方式

@RequestMapping("/upload2")
    public String upload2(HttpServletRequest request,HttpServletResponse response) throws IllegalStateException, IOException{
        //定義解析器,解析上下文
        CommonsMultipartResolver multipartResolver=new CommonsMultipartResolver(request.getSession().getServletContext());
        if(multipartResolver.isMultipart(request)){
            MultipartHttpServletRequest multiRequest=(MultipartHttpServletRequest)request;
            Iterator<String> iter=multiRequest.getFileNames();
            while(iter.hasNext()){
                MultipartFile file=multiRequest.getFile((String)iter.next());
                if(file!=null){
                    String fileName="demoUpload"+file.getOriginalFilename();
                    String path="D:/"+fileName;
                    File f=new File(path);
                    //spring提供的方法將文件複製到本地
                    file.transferTo(f);
                }
            }
        }
        return "/success";
    }

2.普通流的處理效率比較慢代碼如下

@RequestMapping("/upload")
    public String addUser(@RequestParam("file") CommonsMultipartFile file,HttpServletRequest request) throws IOException{
        System.out.println("fileName---->" + file.getOriginalFilename());

        if(!file.isEmpty()){
            try {
                FileOutputStream os = new FileOutputStream("D:/" + new Date().getTime() + file.getOriginalFilename());
                InputStream in = file.getInputStream();
                int b = 0;
                while((b=in.read()) != -1){
                    os.write(b);
                }
                os.flush();
                os.close();
                in.close();
            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        return "/success";
    }