Java如何实现二维码?【附源码】

步骤1

第一步首先创建一个普通的 Maven 项目,然后要实现二维码功能,我们肯定要使用别人提供好的 Jar 包,这里我用的是 google 提供的 jar,pom.xml 文件配置如下:

<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0"          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">     <modelVersion>4.0.0</modelVersion>      <groupId>org.javaboy</groupId>     <artifactId>QRCode</artifactId>     <version>1.0-SNAPSHOT</version>       <dependencies>         <!-- 添加 google 提供的二维码依赖 -->         <dependency>             <groupId>com.google.zxing</groupId>             <artifactId>core</artifactId>             <version>3.3.0</version>         </dependency>     </dependencies>  </project> 

步骤2

然后使用 google 提供的工具类,在项目根目录下创建一个 util 包,将所需要的工具类放进去。

Java如何实现二维码?【附源码】

工具类1 (BufferedImageLuminanceSource)

不废话,直接上代码

package org.javaboy.util;  import java.awt.Graphics2D; import java.awt.geom.AffineTransform; import java.awt.image.BufferedImage;  import com.google.zxing.LuminanceSource;  /**  * @author bai <br/>  * @date 2020/7/1 9:27<br/>  */ public class BufferedImageLuminanceSource extends LuminanceSource {      private final BufferedImage image;     private final int left;     private final int top;      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) & 0xFF000000) == 0) {                     image.setRGB(x, y, 0xFFFFFFFF); // = 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);     }  }  

工具类2 (QRCodeUtil)

这里面可以修改一些参数,例如二维码的尺寸,宽高等等。

package org.javaboy.util;   import java.awt.BasicStroke; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.Image; import java.awt.Shape; import java.awt.geom.RoundRectangle2D; import java.awt.image.BufferedImage; import java.io.File; import java.io.OutputStream; import java.util.Hashtable; import javax.imageio.ImageIO;  import com.google.zxing.BarcodeFormat; import com.google.zxing.BinaryBitmap; import com.google.zxing.DecodeHintType; import com.google.zxing.EncodeHintType; import com.google.zxing.MultiFormatReader; import com.google.zxing.MultiFormatWriter; import com.google.zxing.Result; import com.google.zxing.common.BitMatrix; import com.google.zxing.common.HybridBinarizer; import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;  /**  * @author bai <br/>  * @date 2020/7/1 9:29<br/>  */ 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);         // String file = new Random().nextInt(99999999)+".jpg";         // ImageIO.write(image, FORMAT_NAME, new File(destPath+"/"+file));         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, String destPath) throws Exception {         QRCodeUtil.encode(content, imgPath, destPath, false);     }     // 被注释的方法     /*      * public static void encode(String content, String destPath, boolean      * needCompress) throws Exception { QRCodeUtil.encode(content, null, destPath,      * needCompress); }      */      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));     }  }  

启动类

这一步就是调用方法,一般大家使用这种功能都是为了实现业务,例如常见的扫描二维码跳转链接(页面),扫描二维码出现文字等等。有些二维码中间还带有 Logo 这种图片,将需要嵌入二维码的图片路径准备好就没有问题。

package org.javaboy;  import org.javaboy.util.QRCodeUtil;  /**  * @author bai <br/>  * @date 2020/7/1 9:31<br/>  */ public class QRCodeApplication {     public static void main(String[] args) throws Exception {         // 存放在二维码中的内容         // 二维码中的内容可以是文字,可以是链接等         String text = "http://www.baidu.com";         // 嵌入二维码的图片路径         //String imgPath = "C:\Users\Administrator\Pictures\img\dog.jpg";         // 生成的二维码的路径及名称         String destPath = "C:\Users\bai\Pictures\img\code" + System.currentTimeMillis() + ".jpg";         //生成二维码         QRCodeUtil.encode(text, null, 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);     } }  

效果截图

Java如何实现二维码?【附源码】

源码奉上

码云 https://gitee.com/jian_bo_bai/QRCode

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