code: private static String readQRCode(File filePath, Map hintMap) {
          try {
              BinaryBitmap binaryBitmap = new BinaryBitmap(new HybridBinarizer(
                      new BufferedImageLuminanceSource(ImageIO.read(new FileInputStream(filePath)))));
  
              Result qrCodeResult = new MultiFormatReader().decode(binaryBitmap, hintMap);
              return qrCodeResult.getText();
          } catch (Exception e) {
              e.printStackTrace();
              return null;
          }
      }
docs: 读取二维码信息
  
  @param filePath 文件路径
  @param hintMap  hintMap
  @return 二维码内容