在SpringMVC使用Zxing生成二维码图片：

1. 在Pom.xml引用Zxing

<dependency>
    <groupId>com.google.zxing</groupId>
    <artifactId>core</artifactId>
    <version>3.2.1</version>
</dependency>
<dependency>
    <groupId>com.google.zxing</groupId>
    <artifactId>javase</artifactId>
    <version>3.2.1</version>
</dependency>

2. 在Controller中使用HttpServletResponse输出图片流

@RequestMapping(value = "/ReceivingMoneyQRCode", method = RequestMethod.GET)
    public void ReceivingMoneyQRCode(HttpServletResponse response, String accountCode) throws IOException {

            String url = "要生成二维码的地址" + accountCode;
            ServletOutputStream stream = null;
            try {
                    int width = 200;
                    int height = 200;
                    stream = response.getOutputStream();
                    QRCodeWriter writer = new QRCodeWriter();

                    Hashtable hints = new Hashtable();
                    hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");

                    BitMatrix m = writer.encode(url, BarcodeFormat.QR_CODE, height, width,hints);
                    MatrixToImageWriter.writeToStream(m, "png", stream);
            } catch (WriterException e) {
                    e.printStackTrace();
            } finally {
                    if (stream != null) {
                            stream.flush();
                            stream.close();
                    }
            }
    }

参考

1. 谷歌Zxing二维码，用数据流输出到页面显示

2. 解决中文乱码的问题，因为ZXing默认使用iso-8859-1编码，使用utf-8解决乱码问题：

    Hashtable hints = new Hashtable();
      hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
   
    encode(String contents, BarcodeFormat format, int width, int height,Hashtable hints)
   

   参考：How do I encode characters using UTF-8 in a QR code using Zxing project?

3. 在输出图片流时，提示Can't create output stream!。通过查看日志，发现是因为：Can't create cache file!，再往下是因为AccessDenied，不能在Tomcat中生成临时图片文件。

   通过在启动IntelliJ时，使用管理员身份运行解决。