二维码生成

try {
    //生成QRcode
    BitMatrix matrix = new MultiFormatWriter().encode(shortChain, BarcodeFormat.QR_CODE, 500, 500);

    MatrixToImageWriter.writeToPath(matrix, “PNG”, Paths.get(outFileString));

    //上传七牛，返回URL
    String fileName = UUID.randomUUID().toString()+".png";
    File outImage = Paths.get(outFileString).toFile();

    qrCode.setImageUrl(FileUploadUtils.saveFileInQiNiu(fileName, outImage).getUrl());

    outImage.delete();
} catch (Exception e) {
    e.printStackTrace();