后端将图片文件转化为字节数组字符串，并对其进行Base64编码处理

    public static String getImageStr(String imgFile) {
//        imgFile = "E:/文档/数据/abc.jpg";
        InputStream in = null;
        byte[] data = null;
        // 读取图片字节数组
        try {
            in = new FileInputStream(imgFile);
            data = new byte[in.available()];
            in.read(data);
            in.close();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (java.io.IOException e) {
            e.printStackTrace();
        } finally {
            if (in != null) {
                try {
                    in.close();
                } catch (java.io.IOException e) {
                    e.printStackTrace();
                }
            }
        }
        // 对字节数组Base64编码
        BASE64Encoder encoder = new BASE64Encoder();
        return encoder.encode(data);// 返回Base64编码过的字节数组字符串
    }