<!-- google二維碼工具 -->
<dependency>
 <groupId>com.google.zxing</groupId>
 <artifactId>javase</artifactId>
 <version>3.1.0</version>
</dependency>

<!-- 文件上傳 -->
<dependency>
 <groupId>commons-fileupload</groupId>
 <artifactId>commons-fileupload</artifactId>
 <version>1.3.1</version>
</dependency>
<dependency>
 <groupId>commons-io</groupId>
 <artifactId>commons-io</artifactId>
 <version>2.4</version>
</dependency>

/**
 * 生成二維碼
 * google zxing 實現
 * @param text
 * @return
 */
@RequestMapping(value = "/qrcode/encode", method = RequestMethod.POST)
public void encodeQrCode(String text, HttpServletResponse response) {
  try {
   // 設置二維碼參數
   Map<EncodeHintType, Object> hints = new HashMap<EncodeHintType, Object>();
   hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
   BitMatrix bitMatrix = new MultiFormatWriter().encode(text, BarcodeFormat.QR_CODE, 150, 150, hints);
   //返回二維碼
   MatrixToImageWriter.writeToStream(bitMatrix, "jpg", response.getOutputStream());
  } catch (Exception e) {
   e.printStackTrace();
  }
}

/**
 * 二維碼圖片解碼
 * google zxing 實現
 * @param qrImg
 * @return
 */
@RequestMapping(value = "/qrcode/decode", method = RequestMethod.POST)
public String decodeQrCode(MultipartFile qrImg) {
  if (!qrImg.isEmpty()) {
   try {
     BufferedImage image = ImageIO.read(qrImg.getInputStream());

     BinaryBitmap binaryBitmap = new BinaryBitmap(new HybridBinarizer(new BufferedImageLuminanceSource(image)));

     // 定義二維碼的參數:
     HashMap<DecodeHintType, Object> hints = new HashMap<>();
     // 定義字符集
     hints.put(DecodeHintType.CHARACTER_SET, "utf-8");

     Result result = new MultiFormatReader().decode(binaryBitmap, hints);

     return result.getText();
   } catch (Exception e) {
     e.printStackTrace();
   }
  }

  return null;
}