spring 将FIle 转换成MultipartFile

public static void main(String[] args) {
    File file = new File("C:\\Users\\17146\\Desktop\\a.xlsx");

    FileItemFactory factory = new DiskFileItemFactory(16, null);
    String textFieldName = "textField";
    /**
     源码注释
     * Create a new {@link FileItem} instance from the supplied parameters and
     * any local factory configuration.
     *
     * @param fieldName   The name of the form field.
     * @param contentType The content type of the form field.
     * @param isFormField <code>true</code> if this is a plain form field;
     *                    <code>false</code> otherwise.
     * @param fileName    The name of the uploaded file, if any, as supplied
     *                    by the browser or other client.
     *
     * @return The newly created file item.
     */
    FileItem item = factory.createItem(textFieldName, "text/plain", true, "C:\\Users\\17146\\Desktop\\a.xlsx");
    int bytesRead = 0;
    byte[] buffer = new byte[8192];
    try {
        FileInputStream fis = new FileInputStream(file);
        OutputStream os = item.getOutputStream();
        while ((bytesRead = fis.read(buffer, 0, 8192)) != -1) {
            os.write(buffer, 0, bytesRead);
        }
        os.close();
        fis.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
    MultipartFile multipartFile = new CommonsMultipartFile(item);
     //这是封装pio 将 excel 读取成二位字符串数组   只做类型转换请忽略下面代码
    List<String[]>  list =    readGameExcel(multipartFile);
    for (String[] strings:list ) {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < strings.length; i++) {
            sb.append(Strings.nullToEmpty(strings[i]));
        }
        if(Strings.isNullOrEmpty(sb.toString().replaceAll(" ",""))){
            continue;
        }else {
            for (String s : strings) {
                System.out.print(s + "---");
            }
        }

        System.out.println();
    }
}