MultipartFile save webapp/img，保存图片到本地

saveMultiparFileToLocal.java

private byte[] readInputStream(InputStream inputStream) throws IOException {
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        byte[] buffer = new byte[1024];
        int len = 0;
        while ((len = inputStream.read(buffer)) != -1) {
            outputStream.write(buffer, 0 ,len);
        }
        inputStream.close();
        return outputStream.toByteArray();

    }
public void receiveFile(MultipartFile file, HttpServletRequest request) {
CommonsMultipartFile commonsMultipartFile = (CommonsMultipartFile) file;
        DiskFileItem fileItem = (DiskFileItem) commonsMultipartFile.getFileItem();
        String realPath = request.getServletContext().getRealPath("/");
        String contentType = fileItem.getContentType();
        File imageFile = new File(realPath + "img/" + UUID.randomUUID() + "." +
                contentType.substring(contentType.indexOf
                        ("/") + 1));
        FileOutputStream outputStream = new FileOutputStream(imageFile);
        outputStream.write(readInputStream(fileItem.getInputStream()));
        outputStream.close();
        }