JAVA生成和解析二维码

目的：

通过谷歌的zxing工具生成支付宝和微信均可扫描的二维码。

步骤：

1 添加maven依赖 地址： https://mvnrepository.com/artifact/com.google.zxing/core

<dependency> <groupId>com.google.zxing</groupId> <artifactId>core</artifactId> <version>3.4.0</version> </dependency>

2 编码实现二维码生成工具类 （1）工具类 QRCodeUtil

public class QRCodeUtil { private static Logger logger = LoggerFactory.getLogger(QRCodeUtil.class); public static final String CHARSET = "utf-8"; public static final String FORMAT_NAME = "png"; private static final int BLACK = 0xFF000000; private static final int WHITE = 0xFFFFFFFF; // 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; public 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); //设置二维码四周空白大小 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) ? BLACK : WHITE); } } 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()) { logger.error("" + 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(); // 绘制缩小后的图 g.drawImage(image, 0, 0, null); 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) { BufferedImage image = null; try { image = QRCodeUtil.createImage(content, imgPath, needCompress); logger.info("图片为："+image); mkdirs(destPath); ImageIO.write(image, FORMAT_NAME, new File(destPath)); } catch (Exception e) { logger.error("创建二维码失败：{}",e); } } 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, String destPath) throws Exception { QRCodeUtil.encode(content, imgPath, destPath, false); } public static void encode(String content, String destPath) throws Exception { QRCodeUtil.encode(content, null, destPath, false); } 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); } public static String decode(File file) throws Exception { BufferedImage image; image = ImageIO.read(file); if (image == null) { return null; } BufferedImageLuminanceSource source = new BufferedImageLuminanceSource(image); BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source)); Result result; Hashtable hints = new Hashtable(); hints.put(DecodeHintType.CHARACTER_SET, CHARSET); result = new MultiFormatReader().decode(bitmap, hints); String resultStr = result.getText(); return resultStr; } public static String decode(String path) throws Exception { return QRCodeUtil.decode(new File(path)); } public static void main(String[] args) throws Exception { // 存放在二维码中的内容 String text = "https://me.csdn.net/DJLDYHZSZ"; // 嵌入二维码的图片路径 String filePath = QRCodeUtil.class.getClass().getResource("/").getPath(); System.out.println(filePath.substring(1,filePath.length())); String imgPath = filePath+"META-INF/resources/images/background.jpg"; // 生成的二维码的路径及名称 String destPath = filePath.substring(1,filePath.length())+"META-INF/resources/images/QRCode.png"; //生成二维码 QRCodeUtil.encode(text, imgPath, destPath, true); // 解析二维码 String str = QRCodeUtil.decode(destPath); // 打印出解析出的内容 System.out.println(str); } }

（2）工具类BufferedImageLuminanceSource

作用：这个类层次的目的是抽象在不同平台上的位图，实现成一个标准的接口用于请求灰度的亮度值。

public class BufferedImageLuminanceSource extends LuminanceSource { private final BufferedImage image; private final int left; private final int top; private static final int black = 0xFF000000; private static final int white = 0xFFFFFFFF; public BufferedImageLuminanceSource(BufferedImage image) { this(image, 0, 0, image.getWidth(), image.getHeight()); } public BufferedImageLuminanceSource(BufferedImage image, int left, int top, int width, int height) { super(width, height); int sourceWidth = image.getWidth(); int sourceHeight = image.getHeight(); if (left + width > sourceWidth || top + height > sourceHeight) { throw new IllegalArgumentException("Crop rectangle does not fit within image data."); } for (int y = top; y < top + height; y++) { for (int x = left; x < left + width; x++) { if ((image.getRGB(x, y) & black) == 0) { image.setRGB(x, y, white); } } } this.image = new BufferedImage(sourceWidth, sourceHeight, BufferedImage.TYPE_BYTE_GRAY); this.image.getGraphics().drawImage(image, 0, 0, null); this.left = left; this.top = top; } @Override public byte[] getRow(int y, byte[] row) { if (y < 0 || y >= getHeight()) { throw new IllegalArgumentException("Requested row is outside the image: " + y); } int width = getWidth(); if (row == null || row.length < width) { row = new byte[width]; } image.getRaster().getDataElements(left, top + y, width, 1, row); return row; } @Override public byte[] getMatrix() { int width = getWidth(); int height = getHeight(); int area = width * height; byte[] matrix = new byte[area]; image.getRaster().getDataElements(left, top, width, height, matrix); return matrix; } @Override public boolean isCropSupported() { return true; } @Override public LuminanceSource crop(int left, int top, int width, int height) { return new BufferedImageLuminanceSource(image, this.left + left, this.top + top, width, height); } @Override public boolean isRotateSupported() { return true; } @Override public LuminanceSource rotateCounterClockwise() { int sourceWidth = image.getWidth(); int sourceHeight = image.getHeight(); AffineTransform transform = new AffineTransform(0.0, -1.0, 1.0, 0.0, 0.0, sourceWidth); BufferedImage rotatedImage = new BufferedImage(sourceHeight, sourceWidth, BufferedImage.TYPE_BYTE_GRAY); Graphics2D g = rotatedImage.createGraphics(); g.drawImage(image, transform, null); g.dispose(); int width = getWidth(); return new BufferedImageLuminanceSource(rotatedImage, top, sourceWidth - (left + width), getHeight(), width); }

}

3 将二维码展示给前端

@RestController @RequestMapping("/auth/qrCode/*") public class QRCodeController { private static Logger logger = LoggerFactory.getLogger(QRCodeController.class); /** * 生成不带背景图片的二维码 * @param context * @param response */ @GetMapping("getQRCode.htm") public void getQRCode(@RequestParam String context, HttpServletResponse response) { String filename = "QRCode.png"; try { //BufferedImage 转 InputStream ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream(); ImageOutputStream imageOutput = null; if (StringUtils.isEmpty(context)){ throw new ValidateException("二维码内容不为空"); } BufferedImage image = QRCodeUtil.createImage(context, null, Boolean.TRUE); imageOutput = ImageIO.createImageOutputStream(byteArrayOutputStream); ImageIO.write(image, "png", imageOutput); InputStream inputStream = new ByteArrayInputStream(byteArrayOutputStream.toByteArray()); long length = imageOutput.length(); response.setContentType("application/x-msdownload"); response.setContentLength((int)length); response.setHeader("Content-Disposition","attachment;filename="+new String(filename.getBytes(QRCodeUtil.CHARSET),"iso-8859-1")); //输出流 byte[] bytes = new byte[1024]; OutputStream outputStream = response.getOutputStream(); long count = 0; while(count < length){ int len = inputStream.read(bytes, 0, 1024); count +=len; outputStream.write(bytes, 0, len); } outputStream.flush(); } catch (Exception e) { logger.error("创建二维码失败：{}",e); } } /** * 生成带背景图片的二维码 ——暂时不用 * @param context * @param response */ @GetMapping("getQRCodeByBackgroundImag.htm") public void getQRCodeByBackgroundImag(String context,HttpServletResponse response) { String filename = "QRCode.png"; try { //BufferedImage 转 InputStream ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream(); ImageOutputStream imageOutput = ImageIO.createImageOutputStream(byteArrayOutputStream); Resource resource = SpringContextHolder.getApplicationContext().getResource("classpath:"); File file = resource.getFile(); BufferedImage backgroundImage = QRCodeUtil.createImage("https://blog.csdn.net/static_coder/article/details/78972800", file.getPath() + "/META-INF/resources/images/background.jpg", Boolean.TRUE); String destPath = file.getPath() + "/META-INF/resources/images/dest.png"; QRCodeUtil.mkdirs(destPath); ImageIO.write(backgroundImage, QRCodeUtil.FORMAT_NAME, new File(destPath)); // 生成二维码 BufferedImage destImage =ImageIO.read(new File(destPath)); ImageIO.write(destImage, "png", imageOutput); InputStream inputStream = new ByteArrayInputStream(byteArrayOutputStream.toByteArray()); long length = imageOutput.length(); response.setContentType("application/x-msdownload"); response.setContentLength((int)length); response.setHeader("Content-Disposition","attachment;filename="+new String(filename.getBytes("gbk"),"iso-8859-1")); //输出流 byte[] bytes = new byte[1024]; OutputStream outputStream = response.getOutputStream(); long count = 0; while(count < length){ int len = inputStream.read(bytes, 0, 1024); count +=len; outputStream.write(bytes, 0, len); } outputStream.flush(); } catch (Exception e) { logger.error("创建二维码失败：{}", e); } } }

4 浏览器中展示:

在浏览器中输入地址 ：https://项目域名/auth/qrCode/getQRCode.htm?context=https://me.csdn.net/DJLDYHZSZ 其中context指的的微信或支付宝扫描二维码后进入的网址。 展示二维码如下：

扫描二维码，即可进入我的博客。

注意：如果想生成带背景图片的二维码，只需要在浏览器中请求Controller中的第二个方法即可。