使用zxing提供二维码生成解析服务

搭建一个二维码的生成 & 解析服务, 使用java web对外提供http调用，返回base64格式的二维码图片

1. 背景&准备

二维码生成场景实在是太多了，背景都没啥好说的...

采用的技术

zxing : 实现二维码的生成 & 解析

spring-boot: 提供http服务接口

jdk base64 : 对图片进行base64编码返回

awt : 插入logo

测试case

二维码生成除了传入基本的内容之外，有很多可以配置的参数，比如背景色，前置色，大小，logo，边框...，显然这种多参数配置的情况，我们会采用Builder设计模式来处理，可以看下最终的测试代码如下

/** * 测试二维码 */@Testpublic void testGenQrCode() {    String msg = "https://my.oschina.net/u/566591/blog/1359432";    try {        boolean ans = QrCodeGenWrapper.of(msg).asFile("src/test/qrcode/gen.png");        System.out.println(ans);    } catch (Exception e) {        System.out.println("create qrcode error! e: " + e);        Assert.assertTrue(false);    }    //生成红色的二维码 300x300, 无边框    try {        boolean ans = QrCodeGenWrapper.of(msg)                .setW(300)                .setPreColor(0xffff0000)                .setBgColor(0xffffffff)                .setPadding(0)                .asFile("src/test/qrcode/gen_300x300.png");        System.out.println(ans);    } catch (Exception e) {        System.out.println("create qrcode error! e: " + e);        Assert.assertTrue(false);    }    // 生成带logo的二维码    try {        String logo = "https://static.oschina.net/uploads/user/283/566591_100.jpeg";        boolean ans = QrCodeGenWrapper.of(msg)                .setW(300)                .setPreColor(0xffff0000)                .setBgColor(0xffffffff)                .setPadding(0)                .setLogo(logo)                .setLogoStyle(QrCodeOptions.LogoStyle.ROUND)                .asFile("src/test/qrcode/gen_300x300_logo.png");        System.out.println(ans);    } catch (Exception e) {        System.out.println("create qrcode error! e: " + e);        Assert.assertTrue(false);    }    // 根据本地文件生成待logo的二维码    try {        String logo = "logo.jpg";        boolean ans = QrCodeGenWrapper.of(msg)                .setW(300)                .setPreColor(0xffff0000)                .setBgColor(0xffffffff)                .setPadding(0)                .setLogo(logo)                .asFile("src/test/qrcode/gen_300x300_logo_v2.png");        System.out.println(ans);    } catch (Exception e) {        System.out.println("create qrcode error! e: " + e);        Assert.assertTrue(false);    }}

2. 设计与实现

1. 配置参数: `QrCodeOptions`

根据最常用的规则，目前提供以下可选的配置项

输入内容

logo

logo的样式

宽高

前置色，背景色

输出图片格式

内容编码

@Datapublic class QrCodeOptions {    /**     * 塞入二维码的信息     */    private String msg;    /**     * 二维码中间的logo     */    private String logo;    /**     * logo的样式， 目前支持圆角+普通     */    private LogoStyle logoStyle;    /**     * 生成二维码的宽     */    private Integer w;    /**     * 生成二维码的高     */    private Integer h;    /**     * 生成二维码的颜色     */    private MatrixToImageConfig matrixToImageConfig;    private Map
    
      hints;    /**     * 生成二维码图片的格式 png, jpg     */    private String picType;    public enum LogoStyle {        ROUND,        NORMAL;    }}

从上面的配置来看，有较多其实是与zxing进行打交道的，直接对使用者而言，有点不太友好，下面可以看下我们的包装类

2. 包装类: `QrCodeGenWrapper`

对外提供二维码生成的主要入口，从我们的设计来看，通过of(content) 来创建一个builder对象，并设置二维码的内容，然后可以设置builder中的参数，来选择最终的二维码配置规则

提供三中输出方式:

BufferImage 对象 : 适用于对二维码进行再次处理的场景

二维码图片文件 : 适用于本地生成

base64编码的二维码字符串 : 适用于网络接口调用

下面的实现比较简单，唯一需要注意的就是组装 QrCodeOptions 参数的默认值问题

public class QrCodeGenWrapper {    public static Builder of(String content) {        return new Builder().setMsg(content);    }    private static BufferedImage asBufferedImage(QrCodeOptions qrCodeConfig) throws WriterException, IOException {        BitMatrix bitMatrix = QrCodeUtil.encode(qrCodeConfig);        return QrCodeUtil.toBufferedImage(qrCodeConfig, bitMatrix);    }    private static String asString(QrCodeOptions qrCodeOptions) throws WriterException, IOException {        BufferedImage bufferedImage = asBufferedImage(qrCodeOptions);        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();        ImageIO.write(bufferedImage, qrCodeOptions.getPicType(), outputStream);        return Base64Util.encode(outputStream);    }    private static boolean asFile(QrCodeOptions qrCodeConfig, String absFileName) throws WriterException, IOException {        File file = new File(absFileName);        FileUtil.mkDir(file);        BufferedImage bufferedImage = asBufferedImage(qrCodeConfig);        if (!ImageIO.write(bufferedImage, qrCodeConfig.getPicType(), file)) {            throw new IOException("save qrcode image error!");        }        return true;    }    @ToString    public static class Builder {        private static final MatrixToImageConfig DEFAULT_CONFIG = new MatrixToImageConfig();        /**         * The message to put into QrCode         */        private String msg;        /**         * qrcode center logo         */        private String logo;        /**         * logo的样式         */        private QrCodeOptions.LogoStyle logoStyle = QrCodeOptions.LogoStyle.NORMAL;        /**         * qrcode image width         */        private Integer w;        /**         * qrcode image height         */        private Integer h;        /**         * qrcode bgcolor, default white         */        private Integer bgColor;        /**         * qrcode msg color, default black         */        private Integer preColor;        /**         * qrcode message's code, default UTF-8         */        private String code = "utf-8";        /**         * 0 - 4         */        private Integer padding;        /**         * error level, default H         */        private ErrorCorrectionLevel errorCorrection = ErrorCorrectionLevel.H;        /**         * output qrcode image type, default png         */        private String picType = "png";        public String getMsg() {            return msg;        }        public Builder setMsg(String msg) {            this.msg = msg;            return this;        }        public Builder setLogo(String logo) {            this.logo = logo;            return this;        }        public Builder setLogoStyle(QrCodeOptions.LogoStyle logoStyle) {            this.logoStyle = logoStyle;            return this;        }        public Integer getW() {            return w == null ? (h == null ? 200 : h) : w;        }        public Builder setW(Integer w) {            if (w != null && w <= 0) {                throw new IllegalArgumentException("生成二维码的宽必须大于0");            }            this.w = w;            return this;        }        public Integer getH() {            return h == null ? (w == null ? 200 : w) : h;        }        public Builder setH(Integer h) {            if (h != null && h <= 0) {                throw new IllegalArgumentException("生成功能二维码的搞必须大于0");            }            this.h = h;            return this;        }        public Integer getBgColor() {            return bgColor == null ? MatrixToImageConfig.WHITE : bgColor;        }        public Builder setBgColor(Integer bgColor) {            this.bgColor = bgColor;            return this;        }        public Integer getPreColor() {            return preColor == null ? MatrixToImageConfig.BLACK : preColor;        }        public Builder setPreColor(Integer preColor) {            this.preColor = preColor;            return this;        }        public Builder setCode(String code) {            this.code = code;            return this;        }        public Integer getPadding() {            if (padding == null) {                return 1;            }            if (padding < 0) {                return 0;            }            if (padding > 4) {                return 4;            }            return padding;        }        public Builder setPadding(Integer padding) {            this.padding = padding;            return this;        }        public Builder setPicType(String picType) {            this.picType = picType;            return this;        }        public void setErrorCorrection(ErrorCorrectionLevel errorCorrection) {            this.errorCorrection = errorCorrection;        }        private void validate() {            if (msg == null || msg.length() == 0) {                throw new IllegalArgumentException("生成二维码的内容不能为空!");            }        }        private QrCodeOptions build() {            this.validate();            QrCodeOptions qrCodeConfig = new QrCodeOptions();            qrCodeConfig.setMsg(getMsg());            qrCodeConfig.setH(getH());            qrCodeConfig.setW(getW());            qrCodeConfig.setLogo(logo);            qrCodeConfig.setLogoStyle(logoStyle);            qrCodeConfig.setPicType(picType);            Map
    
      hints = new HashMap<>(3);            hints.put(EncodeHintType.ERROR_CORRECTION, errorCorrection);            hints.put(EncodeHintType.CHARACTER_SET, code);            hints.put(EncodeHintType.MARGIN, this.getPadding());            qrCodeConfig.setHints(hints);            MatrixToImageConfig config;            if (getPreColor() == MatrixToImageConfig.BLACK                    && getBgColor() == MatrixToImageConfig.WHITE) {                config = DEFAULT_CONFIG;            } else {                config = new MatrixToImageConfig(getPreColor(), getBgColor());            }            qrCodeConfig.setMatrixToImageConfig(config);            return qrCodeConfig;        }        public String asString() throws IOException, WriterException {            return QrCodeGenWrapper.asString(build());        }        public BufferedImage asBufferedImage() throws IOException, WriterException {            return QrCodeGenWrapper.asBufferedImage(build());        }        public boolean asFile(String absFileName) throws IOException, WriterException {            return QrCodeGenWrapper.asFile(build(), absFileName);        }    }}

二维码生成工具类 : `QrCodeUtil`

下面这个工具类看着比较复杂，其实大部分代码是从 com.google.zxing.qrcode.QRCodeWriter#encode(String, BarcodeFormat, int, int, Map) 抠出来的

主要是为了解决二维码的白边问题，关于这个大白边问题，可以参看我之前的一篇博文

@Slf4jpublic class QrCodeUtil {    private static final int QUIET_ZONE_SIZE = 4;    /**     * 对 zxing 的 QRCodeWriter 进行扩展, 解决白边过多的问题     * 
     * 源码参考 {@link com.google.zxing.qrcode.QRCodeWriter#encode(String, BarcodeFormat, int, int, Map)}     */    public static BitMatrix encode(QrCodeOptions qrCodeConfig) throws WriterException {        ErrorCorrectionLevel errorCorrectionLevel = ErrorCorrectionLevel.L;        int quietZone = 1;        if (qrCodeConfig.getHints() != null) {            if (qrCodeConfig.getHints().containsKey(EncodeHintType.ERROR_CORRECTION)) {                errorCorrectionLevel = ErrorCorrectionLevel.valueOf(qrCodeConfig.getHints().get(EncodeHintType.ERROR_CORRECTION).toString());            }            if (qrCodeConfig.getHints().containsKey(EncodeHintType.MARGIN)) {                quietZone = Integer.parseInt(qrCodeConfig.getHints().get(EncodeHintType.MARGIN).toString());            }            if (quietZone > QUIET_ZONE_SIZE) {                quietZone = QUIET_ZONE_SIZE;            } else if (quietZone < 0) {                quietZone = 0;            }        }        QRCode code = Encoder.encode(qrCodeConfig.getMsg(), errorCorrectionLevel, qrCodeConfig.getHints());        return renderResult(code, qrCodeConfig.getW(), qrCodeConfig.getH(), quietZone);    }    /**     * 对 zxing 的 QRCodeWriter 进行扩展, 解决白边过多的问题     * 
     * 源码参考 {@link com.google.zxing.qrcode.QRCodeWriter#renderResult(QRCode, int, int, int)}     *     * @param code     * @param width     * @param height     * @param quietZone 取值 [0, 4]     * @return     */    private static BitMatrix renderResult(QRCode code, int width, int height, int quietZone) {        ByteMatrix input = code.getMatrix();        if (input == null) {            throw new IllegalStateException();        }        // xxx 二维码宽高相等, 即 qrWidth == qrHeight        int inputWidth = input.getWidth();        int inputHeight = input.getHeight();        int qrWidth = inputWidth + (quietZone * 2);        int qrHeight = inputHeight + (quietZone * 2);        // 白边过多时, 缩放        int minSize = Math.min(width, height);        int scale = calculateScale(qrWidth, minSize);        if (scale > 0) {            if (log.isDebugEnabled()) {                log.debug("qrCode scale enable! scale: {}, qrSize:{}, expectSize:{}x{}", scale, qrWidth, width, height);            }            int padding, tmpValue;            // 计算边框留白            padding = (minSize - qrWidth * scale) / QUIET_ZONE_SIZE * quietZone;            tmpValue = qrWidth * scale + padding;            if (width == height) {                width = tmpValue;                height = tmpValue;            } else if (width > height) {                width = width * tmpValue / height;                height = tmpValue;            } else {                height = height * tmpValue / width;                width = tmpValue;            }        }        int outputWidth = Math.max(width, qrWidth);        int outputHeight = Math.max(height, qrHeight);        int multiple = Math.min(outputWidth / qrWidth, outputHeight / qrHeight);        int leftPadding = (outputWidth - (inputWidth * multiple)) / 2;        int topPadding = (outputHeight - (inputHeight * multiple)) / 2;        BitMatrix output = new BitMatrix(outputWidth, outputHeight);        for (int inputY = 0, outputY = topPadding; inputY < inputHeight; inputY++, outputY += multiple) {            // Write the contents of this row of the barcode            for (int inputX = 0, outputX = leftPadding; inputX < inputWidth; inputX++, outputX += multiple) {                if (input.get(inputX, inputY) == 1) {                    output.setRegion(outputX, outputY, multiple, multiple);                }            }        }        return output;    }    /**     * 如果留白超过15% , 则需要缩放     * (15% 可以根据实际需要进行修改)     *     * @param qrCodeSize 二维码大小     * @param expectSize 期望输出大小     * @return 返回缩放比例, <= 0 则表示不缩放, 否则指定缩放参数     */    private static int calculateScale(int qrCodeSize, int expectSize) {        if (qrCodeSize >= expectSize) {            return 0;        }        int scale = expectSize / qrCodeSize;        int abs = expectSize - scale * qrCodeSize;        if (abs < expectSize * 0.15) {            return 0;        }        return scale;    }    /**     * 根据二维码配置 & 二维码矩阵生成二维码图片     *     * @param qrCodeConfig     * @param bitMatrix     * @return     * @throws IOException     */    public static BufferedImage toBufferedImage(QrCodeOptions qrCodeConfig, BitMatrix bitMatrix) throws IOException {        int qrCodeWidth = bitMatrix.getWidth();        int qrCodeHeight = bitMatrix.getHeight();        BufferedImage qrCode = new BufferedImage(qrCodeWidth, qrCodeHeight, BufferedImage.TYPE_INT_RGB);        for (int x = 0; x < qrCodeWidth; x++) {            for (int y = 0; y < qrCodeHeight; y++) {                qrCode.setRGB(x, y,                        bitMatrix.get(x, y) ?                                qrCodeConfig.getMatrixToImageConfig().getPixelOnColor() :                                qrCodeConfig.getMatrixToImageConfig().getPixelOffColor());            }        }        // 插入logo        if (!(qrCodeConfig.getLogo() == null || "".equals(qrCodeConfig.getLogo()))) {            ImageUtil.insertLogo(qrCode, qrCodeConfig.getLogo(), qrCodeConfig.getLogoStyle());        }        // 若二维码的实际宽高和预期的宽高不一致, 则缩放        int realQrCodeWidth = qrCodeConfig.getW();        int realQrCodeHeight = qrCodeConfig.getH();        if (qrCodeWidth != realQrCodeWidth || qrCodeHeight != realQrCodeHeight) {            BufferedImage tmp = new BufferedImage(realQrCodeWidth, realQrCodeHeight, BufferedImage.TYPE_INT_RGB);            tmp.getGraphics().drawImage(                    qrCode.getScaledInstance(realQrCodeWidth, realQrCodeHeight,                            Image.SCALE_SMOOTH), 0, 0, null);            qrCode = tmp;        }        return qrCode;    }}

4. logo的插入辅助类： `ImageUtil`

zxing本身是不支持生成待logo的二维码的，这里我们借用awt对将logo绘制在生成的二维码图片上

这里提供了圆角图片生成，边框生成，插入logo三个功能

涉及到绘图的逻辑，也没啥可说的，基本上的套路都一样

public class ImageUtil {    /**     * 在图片中间,插入圆角的logo     *     * @param qrCode 原图     * @param logo   logo地址     * @throws IOException     */    public static void insertLogo(BufferedImage qrCode, String logo, QrCodeOptions.LogoStyle logoStyle) throws IOException {        int QRCODE_WIDTH = qrCode.getWidth();        int QRCODE_HEIGHT = qrCode.getHeight();        // 获取logo图片        BufferedImage bf = getImageByPath(logo);        int size = bf.getWidth() > QRCODE_WIDTH * 2 / 10 ? QRCODE_WIDTH * 2 / 50 : bf.getWidth() / 5;        bf = ImageUtil.makeRoundBorder(bf, logoStyle, size, Color.BLUE); // 边距为二维码图片的1/10        // logo的宽高        int w = bf.getWidth() > QRCODE_WIDTH * 2 / 10 ? QRCODE_WIDTH * 2 / 10 : bf.getWidth();        int h = bf.getHeight() > QRCODE_HEIGHT * 2 / 10 ? QRCODE_HEIGHT * 2 / 10 : bf.getHeight();        // 插入LOGO        Graphics2D graph = qrCode.createGraphics();        int x = (QRCODE_WIDTH - w) / 2;        int y = (QRCODE_HEIGHT - h) / 2;        graph.drawImage(bf, x, y, w, h, null);        graph.dispose();        bf.flush();    }    /**     * 根据路径获取图片     *     * @param path 本地路径 or 网络地址     * @return 图片     * @throws IOException     */    public static BufferedImage getImageByPath(String path) throws IOException {        if (path.startsWith("http")) { // 从网络获取logo//            return ImageIO.read(new URL(path));            return ImageIO.read(HttpUtil.downFile(path));        } else if (path.startsWith("/")) { // 绝对地址获取logo            return ImageIO.read(new File(path));        } else { // 从资源目录下获取logo            return ImageIO.read(ImageUtil.class.getClassLoader().getResourceAsStream(path));        }    }    /**     * fixme 边框的计算需要根据最终生成logo图片的大小来定义，这样才不会出现不同的logo原图，导致边框不一致的问题     *     * 生成圆角图片 & 圆角边框     *     * @param image        原图     * @param logoStyle 圆角的角度     * @param size         边框的边距     * @param color        边框的颜色     * @return 返回带边框的圆角图     */    public static BufferedImage makeRoundBorder(BufferedImage image, QrCodeOptions.LogoStyle logoStyle, int size, Color color) {        // 将图片变成圆角        int cornerRadius = 0;        if (logoStyle == QrCodeOptions.LogoStyle.ROUND) {            cornerRadius = 30;            image = makeRoundedCorner(image, cornerRadius);        }        int borderSize = size;        int w = image.getWidth() + borderSize;        int h = image.getHeight() + borderSize;        BufferedImage output = new BufferedImage(w, h,                BufferedImage.TYPE_INT_ARGB);        Graphics2D g2 = output.createGraphics();        g2.setComposite(AlphaComposite.Src);        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,                RenderingHints.VALUE_ANTIALIAS_ON);        g2.setColor(color == null ? Color.WHITE : color);        g2.fill(new RoundRectangle2D.Float(0, 0, w, h, cornerRadius,                cornerRadius));        // ... then compositing the image on top,        // using the white shape from above as alpha source        g2.setComposite(AlphaComposite.SrcAtop);        g2.drawImage(image, size, size, null);        g2.dispose();        return output;    }    /**     * 生成圆角图片     *     * @param image        原始图片     * @param cornerRadius 圆角的弧度     * @return 返回圆角图     */    public static BufferedImage makeRoundedCorner(BufferedImage image,                                                  int cornerRadius) {        int w = image.getWidth();        int h = image.getHeight();        BufferedImage output = new BufferedImage(w, h,                BufferedImage.TYPE_INT_ARGB);        Graphics2D g2 = output.createGraphics();        // This is what we want, but it only does hard-clipping, i.e. aliasing        // g2.setClip(new RoundRectangle2D ...)        // so instead fake soft-clipping by first drawing the desired clip shape        // in fully opaque white with antialiasing enabled...        g2.setComposite(AlphaComposite.Src);        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,                RenderingHints.VALUE_ANTIALIAS_ON);        g2.setColor(Color.WHITE);        g2.fill(new RoundRectangle2D.Float(0, 0, w, h, cornerRadius,                cornerRadius));        // ... then compositing the image on top,        // using the white shape from above as alpha source        g2.setComposite(AlphaComposite.SrcAtop);        g2.drawImage(image, 0, 0, null);        g2.dispose();        return output;    }}

5. base64编码工具: `Base64Util`

public class Base64Util {    public static String encode(ByteArrayOutputStream outputStream) {        return Base64.getEncoder().encodeToString(outputStream.toByteArray());    }}

6. 二维码解析工具: `QrCodeDeWrapper`

public class QrCodeDeWrapper {    /**     * 读取二维码中的内容, 并返回     *     * @param qrcodeImg 二维码图片的地址     * @return 返回二维码的内容     * @throws IOException       读取二维码失败     * @throws FormatException   二维码解析失败     * @throws ChecksumException     * @throws NotFoundException     */    public static String decode(String qrcodeImg) throws IOException, FormatException, ChecksumException, NotFoundException {        BufferedImage image = ImageUtil.getImageByPath(qrcodeImg);        return decode(image);    }    public static String decode(BufferedImage image) throws FormatException, ChecksumException, NotFoundException {        if (image == null) {            throw new IllegalStateException("can not load qrCode!");        }        LuminanceSource source = new BufferedImageLuminanceSource(image);        BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));        QRCodeReader qrCodeReader = new QRCodeReader();        Result result = qrCodeReader.decode(bitmap);        return result.getText();    }}