Konvertieren Sie zwischen Datei und MultipartFile

 /**
     * MultipartFile 转 File
     *
     * @param multipartFile
     * @throws Exception
     */
    public static File MultipartFileToFile(MultipartFile multipartFile) {

        File file = null;
        //判断是否为null
        if (multipartFile.equals("") || multipartFile.getSize() <= 0) {
            return file;
        }
        //MultipartFile转换为File
        InputStream ins = null;
        OutputStream os = null;
        try {
            ins = multipartFile.getInputStream();
            file = new File(multipartFile.getOriginalFilename());
            os = new FileOutputStream(file);
            int bytesRead = 0;
            byte[] buffer = new byte[8192];
            while ((bytesRead = ins.read(buffer, 0, 8192)) != -1) {
                os.write(buffer, 0, bytesRead);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            if(os != null){
                try {
                    os.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if(ins != null){
                try {
                    ins.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return file;
    }

    /**
     * File 转 MultipartFile
     *
     * @param file
     * @throws Exception
     */
    public static MultipartFile fileToMultipartFile(File file) throws Exception {
        String fileName = file.getName();
        String contentType = getContentType(fileName);
        MultipartFile multipartFile = new MockMultipartFile(fileName, fileName,contentType,new FileInputStream(file));
        return multipartFile;
    }