利用Spring Boot+zxing，生成二维码还能这么简单

在网站开发中,经常会遇到要生成二维码的情况,比如要使用微信支付、网页登录等，本文分享一个Spring Boot生成二维码的例子,这里用到了google的zxing工具类。

1.引入jar包

pom.xml中引入zxing的jar包。

    com.google.zxing
    core
    3.2.0


    com.google.zxing
    javase
    3.2.0

2.编写工具类

QRCodeUtil.java代码如下：

import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.geom.RoundRectangle2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.OutputStream;
import java.util.Hashtable;

/**
 * QRCodeUtil 生成二维码工具类
 */
public class QRCodeUtil {

    private static final String CHARSET = "utf-8";
    private static final String FORMAT_NAME = "JPG";
    // 二维码尺寸
    private static final int QRCODE_SIZE = 300;
    // LOGO宽度
    private static final int WIDTH = 60;
    // LOGO高度
    private static final int HEIGHT = 60;

    private static BufferedImage createImage(String content, String imgPath, boolean needCompress) throws Exception {
        Hashtable hints = new Hashtable();
        hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
        hints.put(EncodeHintType.CHARACTER_SET, CHARSET);
        hints.put(EncodeHintType.MARGIN, 1);
        BitMatrix bitMatrix = new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE, QRCODE_SIZE, QRCODE_SIZE,
                hints);
        int width = bitMatrix.getWidth();
        int height = bitMatrix.getHeight();
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        for (int x = 0; x < width; x++) {
            for (int y = 0; y < height; y++) {
                image.setRGB(x, y, bitMatrix.get(x, y) ? 0xFF000000 : 0xFFFFFFFF);
            }
        }
        if (imgPath == null || "".equals(imgPath)) {
            return image;
        }
        // 插入图片
        QRCodeUtil.insertImage(image, imgPath, needCompress);
        return image;
    }

    private static void insertImage(BufferedImage source, String imgPath, boolean needCompress) throws Exception {
        File file = new File(imgPath);
        if (!file.exists()) {
            System.err.println("" + imgPath + "   该文件不存在！");
            return;
        }
        Image src = ImageIO.read(new File(imgPath));
        int width = src.getWidth(null);
        int height = src.getHeight(null);
        if (needCompress) { // 压缩LOGO
            if (width > WIDTH) {
                width = WIDTH;
            }
            if (height > HEIGHT) {
                height = HEIGHT;
            }
            Image image = src.getScaledInstance(width, height, Image.SCALE_SMOOTH);
            BufferedImage tag = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            Graphics g = tag.getGraphics();
            g.drawImage(image, 0, 0, null); // 绘制缩小后的图
            g.dispose();
            src = image;
        }
        // 插入LOGO
        Graphics2D graph = source.createGraphics();
        int x = (QRCODE_SIZE - width) / 2;
        int y = (QRCODE_SIZE - height) / 2;
        graph.drawImage(src, x, y, width, height, null);
        Shape shape = new RoundRectangle2D.Float(x, y, width, width, 6, 6);
        graph.setStroke(new BasicStroke(3f));
        graph.draw(shape);
        graph.dispose();
    }

    public static void encode(String content, String imgPath, String destPath, boolean needCompress) throws Exception {
        BufferedImage image = QRCodeUtil.createImage(content, imgPath, needCompress);
        mkdirs(destPath);
        ImageIO.write(image, FORMAT_NAME, new File(destPath));
    }

    public static BufferedImage encode(String content, String imgPath, boolean needCompress) throws Exception {
        BufferedImage image = QRCodeUtil.createImage(content, imgPath, needCompress);
        return image;
    }

    public static void mkdirs(String destPath) {
        File file = new File(destPath);
        // 当文件夹不存在时，mkdirs会自动创建多层目录，区别于mkdir．(mkdir如果父目录不存在则会抛出异常)
        if (!file.exists() && !file.isDirectory()) {
            file.mkdirs();
        }
    }

    public static void encode(String content, String imgPath, OutputStream output, boolean needCompress)
            throws Exception {
        BufferedImage image = QRCodeUtil.createImage(content, imgPath, needCompress);
        ImageIO.write(image, FORMAT_NAME, output);
    }

    public static void encode(String content, OutputStream output) throws Exception {
        QRCodeUtil.encode(content, null, output, false);
    }
}

3.编写控制层代码

QrCodeController.java代码如下：

    /**
     * 根据 url 生成 普通二维码
     */
    @RequestMapping(value = "/createCommonQRCode")
    public void createCommonQRCode(HttpServletResponse response, String url) throws Exception {
        ServletOutputStream stream = null;
        try {
            stream = response.getOutputStream();
            //使用工具类生成二维码
            QRCodeUtil.encode(url, stream);
        } catch (Exception e) {
            e.getStackTrace();
        } finally {
            if (stream != null) {
                stream.flush();
                stream.close();
            }
        }
    }

    /**
     * 根据 url 生成 带有logo二维码
     */
    @RequestMapping(value = "/createLogoQRCode")
    public void createLogoQRCode(HttpServletResponse response, String url) throws Exception {
        ServletOutputStream stream = null;
        try {
            stream = response.getOutputStream();
            String logoPath = Thread.currentThread().getContextClassLoader().getResource("").getPath() 
                    + "templates" + File.separator + "logo.jpg";
            //使用工具类生成二维码
            QRCodeUtil.encode(url, logoPath, stream, true);
        } catch (Exception e) {
            e.getStackTrace();
        } finally {
            if (stream != null) {
                stream.flush();
                stream.close();
            }
        }
    }

4.运行并查看效果

本项目中提供了生成普通二维码和带有logo二维码的两个接口，启动项目，我们来演示下生成下http://www.baidu.com这个url的二维码；

1. 生成普通二维码
   本地浏览器打开http://localhost:8080/createCommonQRCode?url=http://www.baidu.com，生成的二维码截图如下：

    2.生成带logo的二维码
本地浏览器打开http://localhost:8080/createLogoQRCode?url=http://www.baidu.com，生成的二维码截图如下：