使用Zxing二维码生成

1、引用依赖

        <dependency>
            <groupId>com.google.zxing</groupId>
            <artifactId>javase</artifactId>
            <version>3.3.3</version>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.2.11</version>
        </dependency>

2、生成二维码工具类QrCodeUtil 

package com.qingfeng.qianduan.utils;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Hashtable;
import javax.imageio.ImageIO;
import com.alibaba.druid.util.StringUtils;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.WriterException;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;

/**
 * 生成二维码
 */
public class QrCodeUtil {

    private static final int BLACK = 0xFF000000;
    private static final int WHITE = 0xFFFFFFFF;
    private static final int margin = 0;
    private static final int LogoPart = 4;

    /**
     * 设置生成二维码矩阵信息
     * @param content 二维码图片内容
     * @param width   二维码图片宽度
     * @param height  二维码图片高度
     * @throws WriterException
     */
    public static BitMatrix setBitMatrix(String content, int width, int height) throws WriterException {
        BitMatrix bitMatrix = null;
        Hashtable<EncodeHintType, Object> hints = new Hashtable<EncodeHintType, Object>();
        hints.put(EncodeHintType.CHARACTER_SET, "UTF-8"); // 指定编码方式,避免中文乱码
        hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H); // 指定纠错等级 如果二维码里面的内容比较多的话推荐使用H 容错率30%， 这样可以避免一些扫描不出来的问题
        hints.put(EncodeHintType.MARGIN, margin); // 指定二维码四周白色区域大小 官方的这个方法目前没有没有作用默认设置为0
        bitMatrix = new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE, width, height, hints);
        return bitMatrix;
    }
    /**
     * @param matrix
     * @param format
     * @param outStream
     * @param logoPath        logo图片
     * @param reduceWhiteArea 二维码空白区域设置
     * @throws IOException
     */
    public static void writeToFile(BitMatrix matrix, String format, OutputStream outStream, String logoPath, int reduceWhiteArea) throws IOException {
        BufferedImage image = toBufferedImage(matrix, reduceWhiteArea);
        // 如果设置了二维码里面的logo 加入LOGO水印
        if (!StringUtils.isEmpty(logoPath)) {
            image = addLogo(image, logoPath);
        }
        ImageIO.write(image, format, outStream);
    }

    /**
     *
     * @param matrix
     * @param reduceWhiteArea
     * @return
     */
    public static BufferedImage toBufferedImage(BitMatrix matrix, int reduceWhiteArea) {
        int width = matrix.getWidth();
        int height = matrix.getHeight();
        BufferedImage image = new BufferedImage(width - 2 * reduceWhiteArea, height - 2 * reduceWhiteArea, BufferedImage.TYPE_3BYTE_BGR);
        for (int x = reduceWhiteArea; x < width - reduceWhiteArea; x++) {
            for (int y = reduceWhiteArea; y < height - reduceWhiteArea; y++) {
                image.setRGB(x - reduceWhiteArea, y - reduceWhiteArea, matrix.get(x, y) ? BLACK : WHITE);
            }
        }
        return image;
    }

    /**
     * 给二维码图片中绘制logo信息 非必须
     * @param image    二维码图片
     * @param logoPath logo图片路径
     */
    public static BufferedImage addLogo(BufferedImage image, String logoPath) throws IOException {
        Graphics2D g = image.createGraphics();
        BufferedImage logoImage = ImageIO.read(new File(logoPath));
        // 计算logo图片大小,可适应长方形图片,根据较短边生成正方形
        int width = image.getWidth() < image.getHeight() ? image.getWidth() / LogoPart : image.getHeight() / LogoPart;
        int height = width;
        // 计算logo图片放置位置
        int x = (image.getWidth() - width) / 2;
        int y = (image.getHeight() - height) / 2;
        // 在二维码图片上绘制中间的logo
        g.drawImage(logoImage, x, y, width, height, null);
        // 绘制logo边框,可选
        g.setStroke(new BasicStroke(2)); // 画笔粗细
        g.setColor(Color.WHITE); // 边框颜色
        g.drawRect(x, y, width, height); // 矩形边框
        logoImage.flush();
        g.dispose();
        return image;
    }

}

3、测试生成二维码

    //http://localhost:10000/QrCode
    @RequestMapping("/QrCode")
    public void QrCode() throws WriterException {
        //二维码内容
        String content = "生成二维码";
        String logoPath = "D:/logo.png"; // 二维码中间的logo信息 非必须
        String format = "jpg";
        int width = 120; // 二维码宽度
        int height = 120;// 二维码高度
        // 设置二维码矩阵的信息
        BitMatrix bitMatrix = QrCodeUtil.setBitMatrix(content, width, height);
        // 设置输出流
        OutputStream outStream = null;
        String path = "D:/QrCode/" + new Date().getTime() + ".png";//设置二维码的文件名
        try {
            outStream = new FileOutputStream(new File(path));
            // 目前 针对容错等级为H reduceWhiteArea  二维码空白区域的大小 根据实际情况设置，如果二维码内容长度不固定的话 需要自己根据实际情况计算reduceWhiteArea的大小
            QrCodeUtil.writeToFile(bitMatrix, format, outStream, null, 5);
            outStream.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

参考：https://blog.csdn.net/xishining/article/details/128700068