生成二维码案例

1.引入依赖

<!-- zxing生成二维码 -->
<dependency><groupId>com.google.zxing</groupId><artifactId>core</artifactId><version>3.3.3</version>
</dependency><dependency><groupId>com.google.zxing</groupId><artifactId>javase</artifactId><version>3.3.3</version>
</dependency>

2.生成二维码工具包

/*** 二维码工具* @Author:debug (SteadyJack)* @Link: weixin-> debug0868  qq-> 1948831260* @Date: 2020/11/16 22:38**/
public class QRCodeUtil {private static final Logger log= LoggerFactory.getLogger(QRCodeUtil.class);//CODE_WIDTH：二维码宽度，单位像素private static final int CODE_WIDTH = 400;//CODE_HEIGHT：二维码高度，单位像素private static final int CODE_HEIGHT = 400;//FRONT_COLOR：二维码前景色，0x000000 表示黑色private static final int FRONT_COLOR = 0x000000;//BACKGROUND_COLOR：二维码背景色，0xFFFFFF 表示白色//演示用 16 进制表示，和前端页面 CSS 的取色是一样的，注意前后景颜色应该对比明显，如常见的黑白private static final int BACKGROUND_COLOR = 0xFFFFFF;public static void createCodeToFile(String content, File codeImgFileSaveDir, String fileName) {try {if (StringUtils.isBlank(content) || StringUtils.isBlank(fileName)) {return;}content = content.trim();if (codeImgFileSaveDir==null || codeImgFileSaveDir.isFile()) {//二维码图片存在目录为空，默认放在桌面...codeImgFileSaveDir = FileSystemView.getFileSystemView().getHomeDirectory();}if (!codeImgFileSaveDir.exists()) {//二维码图片存在目录不存在，开始创建...codeImgFileSaveDir.mkdirs();}//核心代码-生成二维码BufferedImage bufferedImage = getBufferedImage(content);File codeImgFile = new File(codeImgFileSaveDir, fileName);ImageIO.write(bufferedImage, "png", codeImgFile);log.info("二维码图片生成成功：" + codeImgFile.getPath());} catch (Exception e) {e.printStackTrace();}}/*** 生成二维码并输出到输出流, 通常用于输出到网页上进行显示，输出到网页与输出到磁盘上的文件中，区别在于最后一句 ImageIO.write* write(RenderedImage im,String formatName,File output)：写到文件中* write(RenderedImage im,String formatName,OutputStream output)：输出到输出流中* @param content  ：二维码内容* @param outputStream ：输出流，比如 HttpServletResponse 的 getOutputStream*/public static void createCodeToOutputStream(String content, OutputStream outputStream) {try {if (StringUtils.isBlank(content)) {return;}content = content.trim();//核心代码-生成二维码BufferedImage bufferedImage = getBufferedImage(content);//图片路径addQrCodeLogo(bufferedImage,new File("E://shFiles//QRCode//20231213151849.png"));//区别就是这一句，输出到输出流中，如果第三个参数是 File，则输出到文件中ImageIO.write(bufferedImage, "png", outputStream);log.info("二维码图片生成到输出流成功...");} catch (Exception e) {e.printStackTrace();}}//核心代码-生成二维码private static BufferedImage getBufferedImage(String content) throws WriterException {//com.google.zxing.EncodeHintType：编码提示类型,枚举类型Map<EncodeHintType, Object> hints = new HashMap();//EncodeHintType.CHARACTER_SET：设置字符编码类型hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");//EncodeHintType.ERROR_CORRECTION：设置误差校正//ErrorCorrectionLevel：误差校正等级，L = ~7% correction、M = ~15% correction、Q = ~25% correction、H = ~30% correction//不设置时，默认为 L 等级，等级不一样，生成的图案不同，但扫描的结果是一样的hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.M);//EncodeHintType.MARGIN：设置二维码边距，单位像素，值越小，二维码距离四周越近hints.put(EncodeHintType.MARGIN, 1);MultiFormatWriter multiFormatWriter = new MultiFormatWriter();BitMatrix bitMatrix = multiFormatWriter.encode(content, BarcodeFormat.QR_CODE, CODE_WIDTH, CODE_HEIGHT, hints);BufferedImage bufferedImage = new BufferedImage(CODE_WIDTH, CODE_HEIGHT, BufferedImage.TYPE_INT_BGR);for (int x = 0; x < CODE_WIDTH; x++) {for (int y = 0; y < CODE_HEIGHT; y++) {bufferedImage.setRGB(x, y, bitMatrix.get(x, y) ? FRONT_COLOR : BACKGROUND_COLOR);}}return bufferedImage;}/*** 二维码下载方法* @param url* @param fileName* @param request* @param response*/public static void downFile(String url, String fileName, HttpServletRequest request, HttpServletResponse response) {try {//1.定义ContentType为("multipart/form-data")让浏览器自己解析文件格式response.setContentType("multipart/form-data");//2.中文名转码//response.setHeader("Content-disposition", "attachment; filename=\""+encodeChineseDownloadFileName(request, fileName+".xlsx") +"\"");response.setHeader("Content-Disposition", "attachment;filename=" + new String(fileName.getBytes("UTF-8"), "ISO-8859-1"));//获得文件File file = new File(url+fileName);FileInputStream in = new FileInputStream(file);//3.将文件写入缓冲区OutputStream(out)OutputStream out = new BufferedOutputStream(response.getOutputStream());int b = 0;byte[] buffer = new byte[2048];while ((b=in.read(buffer)) != -1){//4.将缓冲区文件输出到客户端(out)out.write(buffer,0,b);}in.close();out.flush();out.close();} catch (IOException e) {e.printStackTrace();}}/*** 给二维码添加logo* @Date 2023/09/24 22:33* @Param [bufferedImage, logoFile]* @return java.awt.image.BufferedImage*/public static BufferedImage addQrCodeLogo(BufferedImage bufferedImage, File logoFile) throws IOException {Graphics2D graphics = bufferedImage.createGraphics();int matrixWidth = bufferedImage.getWidth();int matrixHeigh = bufferedImage.getHeight();// 读取logo图片文件BufferedImage logo = ImageIO.read(logoFile);int logoWidth = logo.getWidth();int logoHeight = logo.getHeight();//  计算logo放置位置int x = bufferedImage.getWidth()  / 5*2;int y = bufferedImage.getHeight() / 5*2;int width = matrixWidth / 5;int height = matrixHeigh / 5;// 开始绘制图片graphics.drawImage(logo, x, y, width, height, null);graphics.drawRoundRect(x, y, logoWidth, logoHeight, 15, 15);graphics.setStroke(new BasicStroke(5.0F, 1, 1));graphics.setColor(Color.white);graphics.drawRect(x, y, logoWidth, logoHeight);graphics.dispose();bufferedImage.flush();return bufferedImage;}}

3.Controller 中调用生成二维码工具包

@RestController
@RequestMapping("/qrCode")
public class QrCodeController {private static final String RootPath="H:\\shFiles\\QRCode";private static final String FileFormat=".png";private static final ThreadLocal<SimpleDateFormat> LOCALDATEFORMAT=ThreadLocal.withInitial(() -> new SimpleDateFormat("yyyyMMddHHmmss"));//生成二维码并将其存放于本地目录@PostMapping("generate/file")public AjaxResult generateV1(String content){try {final String fileName=LOCALDATEFORMAT.get().format(new Date());File file = null;QRCodeUtil.createCodeToFile(content,file,fileName+FileFormat);}catch (Exception e){return AjaxResult.error(e.getMessage());}return AjaxResult.success();}//生成二维码并将其返回给前端调用者@PostMapping("generate/img")public AjaxResult generateV2(String content,HttpServletResponse servletResponse){try {QRCodeUtil.createCodeToOutputStream(content,servletResponse.getOutputStream());}catch (Exception e){return AjaxResult.error(e.getMessage());}return AjaxResult.success();}}

4.在postman测试