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前言
这里讲解一下条形码与二维码的基础知识与应用.
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概念
条形码(barcode)
- 以一组宽度不同的黑条和空白,安照一定编码规则,用来表示一组信息的图形标识.
- 标识一串数字或字母.
- 一般容量小于30个数字或字母
二维码(QRcode)
- 又叫二维条形码.
- 用特定的几何图形按照一定规律在平面上分布的黑白相间的图形.
- 能够存储数字,字母,汉字,图片等.
- 字符集128个字符
- 可存储<几十kb
- 抗损坏
实践
常用类包
| 名称 | 特点 |
|---|---|
| Zxing(Google) | 支持1D,2D的barcode |
| Barcode4J | 纯java生成,只负责生成,不负责解析 |
Zxing
Maven依赖
<dependency> <groupId>com.google.zxing</groupId> <artifactId>javase</artifactId> <version>3.3.3</version> </dependency> 条形码
/** * generateCode 根据code生成相应的一维码 * @param file 一维码目标文件 * @param code 一维码内容 * @param width 图片宽度 * @param height 图片高度 */ public static void generateCode(File file, String code, int width, int height) { //定义位图矩阵BitMatrix BitMatrix matrix = null; try { // 使用code_128格式进行编码生成100*25的条形码 MultiFormatWriter writer = new MultiFormatWriter(); matrix = writer.encode(code,BarcodeFormat.CODE_128, width, height, null); //matrix = writer.encode(code,BarcodeFormat.EAN_13, width, height, null); } catch (WriterException e) { e.printStackTrace(); } //将位图矩阵BitMatrix保存为图片 try (FileOutputStream outStream = new FileOutputStream(file)) { ImageIO.write(MatrixToImageWriter.toBufferedImage(matrix), "png", outStream); outStream.flush(); } catch (Exception e) { e.printStackTrace(); } } /** * readCode 读取一张一维码图片 * @param file 一维码图片名字 */ public static void readCode(File file){ try { BufferedImage image = ImageIO.read(file); if (image == null) { return; } LuminanceSource source = new BufferedImageLuminanceSource(image); BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source)); Map<DecodeHintType, Object> hints = new HashMap<>(); hints.put(DecodeHintType.CHARACTER_SET, "GBK"); hints.put(DecodeHintType.PURE_BARCODE, Boolean.TRUE); hints.put(DecodeHintType.TRY_HARDER, Boolean.TRUE); Result result = new MultiFormatReader().decode(bitmap, hints); System.out.println("条形码内容: "+result.getText()); } catch (Exception e) { e.printStackTrace(); } } 
二维码
/* * 定义二维码的宽高 */ private static int WIDTH = 300; private static int HEIGHT = 300; private static String FORMAT = "png";//二维码格式 //生成二维码 public static void generateQRCode(File file, String content) { //定义二维码参数 Map<EncodeHintType, Object> hints = new HashMap<>(); hints.put(EncodeHintType.CHARACTER_SET, "utf-8");//设置编码 hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.M);//设置容错等级 hints.put(EncodeHintType.MARGIN, 2);//设置边距默认是5 try { BitMatrix bitMatrix = new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE, WIDTH, HEIGHT, hints); Path path = file.toPath(); MatrixToImageWriter.writeToPath(bitMatrix, FORMAT, path);//写到指定路径下 } catch (Exception e) { e.printStackTrace(); } } //读取二维码 public static void readQrCode(File file) { MultiFormatReader reader = new MultiFormatReader(); try { BufferedImage image = ImageIO.read(file); BinaryBitmap binaryBitmap = new BinaryBitmap(new HybridBinarizer(new BufferedImageLuminanceSource(image))); Map<DecodeHintType, Object> hints = new HashMap<>(); hints.put(DecodeHintType.CHARACTER_SET, "utf-8");//设置编码 Result result = reader.decode(binaryBitmap, hints); System.out.println("解析结果:" + result.toString()); System.out.println("二维码格式:" + result.getBarcodeFormat()); System.out.println("二维码文本内容:" + result.getText()); } catch (Exception e) { e.printStackTrace(); } } 
Barcode4J
Maven依赖
<dependency> <groupId>net.sf.barcode4j</groupId> <artifactId>barcode4j</artifactId> <version>2.1</version> </dependency> <dependency> <groupId>org.apache.avalon.framework</groupId> <artifactId>avalon-framework-api</artifactId> <version>4.3.1</version> </dependency> 条形码
public static void generateFile(String msg, String path) { File file = new File(path); try { Code39Bean bean = new Code39Bean(); //EAN13Bean bean = new EAN13Bean(); // dpi精度 final int dpi = 150; // module宽度 //bean.setModuleWidth(0.2); final double width = UnitConv.in2mm(2.0f / dpi); bean.setWideFactor(3); bean.setModuleWidth(width); bean.doQuietZone(false); String format = "image/png"; // 输出到流 BitmapCanvasProvider canvas = new BitmapCanvasProvider(new FileOutputStream(file), format, dpi, BufferedImage.TYPE_BYTE_BINARY, false, 0); // 生成条形码 bean.generateBarcode(canvas, msg); // 结束绘制 canvas.finish(); } catch (Exception e) { e.printStackTrace(); } } 二维码
public static void main(String[] args) throws Exception { BarcodeUtil util = BarcodeUtil.getInstance(); BarcodeGenerator gen = util.createBarcodeGenerator(buildCfg("datamatrix")); OutputStream fout = new FileOutputStream("2dcode.png"); int resolution = 300; BitmapCanvasProvider canvas = new BitmapCanvasProvider(fout, "image/png", resolution, BufferedImage.TYPE_BYTE_BINARY, false, 0); gen.generateBarcode(canvas, "be the coder"); canvas.finish(); } private static Configuration buildCfg(String type) { DefaultConfiguration cfg = new DefaultConfiguration("barcode"); // Bar code type DefaultConfiguration child = new DefaultConfiguration(type); cfg.addChild(child); // Human readable text position DefaultConfiguration attr = new DefaultConfiguration("human-readable"); // DefaultConfiguration subAttr = new DefaultConfiguration("placement"); // subAttr.setValue("bottom"); // attr.addChild(subAttr); // child.addChild(attr); // datamatrix code has no human-readable part // see http://barcode4j.sourceforge.net/2.1/symbol-datamatrix.html attr = new DefaultConfiguration("height"); attr.setValue(50); child.addChild(attr); attr = new DefaultConfiguration("module-width"); attr.setValue("0.6"); child.addChild(attr); return cfg; } 总结
- 注意条形码种类
- 高并发时,注意生成速度
- api较多,需要多查询,练习
参见
文章来源: https://blog.csdn.net/weixin_38500325/article/details/88842454