java实现电脑端扫描二维码

下面是Java实现电脑端扫描二维码的攻略。

一、使用Zxing库实现

Zxing是一个开源的条码/二维码处理库，可以通过它来实现二维码的生成和解码。下面是实现步骤：

1. 引入依赖

在pom.xml文件中添加如下依赖：

xml
<dependency>
<groupId>com.google.zxing</groupId>
<artifactId>core</artifactId>
<version>3.4.1</version>
</dependency>
<dependency>
<groupId>com.google.zxing</groupId>
<artifactId>javase</artifactId>
<version>3.4.1</version>
</dependency>

1. 编写生成二维码的代码

java
//生成二维码
public static void encode(String contents, String filePath) {
int width = 300, height = 300;
String format = "png";
Map<EncodeHintType, Object> hints = new HashMap<>();
hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
BitMatrix bitMatrix;
try {
bitMatrix = new MultiFormatWriter().encode(contents, BarcodeFormat.QR_CODE, width, height, hints);
} catch (WriterException e) {
e.printStackTrace();
return;
}
Path path = FileSystems.getDefault().getPath(filePath);
MatrixToImageWriter.writeToPath(bitMatrix, format, path);
}

1. 编写解码二维码的代码

```java
//解码二维码
public static String decode(String filePath) {
BufferedImage image;
try {
image = ImageIO.read(new File(filePath));
} catch (IOException e) {
e.printStackTrace();
return null;
}

   if (image == null) {
       System.out.println("Could not decode image");
       return null;
   }

   BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(new BufferedImageLuminanceSource(image)));
   Result result;
   Map<DecodeHintType, Object> hints = new HashMap<>();
   hints.put(DecodeHintType.CHARACTER_SET, "UTF-8");
   try {
       result = new MultiFormatReader().decode(bitmap, hints);
   } catch (NotFoundException e) {
       System.out.println("Could not decode image");
       return null;
   }
   return result.getText();

}
```

1. 在main方法中调用

java
public static void main(String[] args) {
String text = "二维码内容";
String filePath = "二维码存放路径";
//生成二维码
QRCodeUtil.encode(text, filePath);
//解码二维码
String content = QRCodeUtil.decode(filePath);
System.out.println(content);
}

二、使用JavaFX实现

JavaFX是Java平台上的一种富客户端应用程序用户界面框架，其可以用来开发桌面应用程序。下面是实现步骤：

1. 引入依赖

在pom.xml文件中添加如下依赖：

xml
<dependency>
<groupId>com.google.zxing</groupId>
<artifactId>core</artifactId>
<version>3.4.1</version>
</dependency>
<dependency>
<groupId>com.google.zxing</groupId>
<artifactId>javase</artifactId>
<version>3.4.1</version>
</dependency>
<dependency>
<groupId>com.jfoenix</groupId>
<artifactId>jfoenix</artifactId>
<version>8.0.10</version>
</dependency>
<dependency>
<groupId>de.jensd</groupId>
<artifactId>fontawesomefx-materialdesign-fonts</artifactId>
<version>2.2.0-9.14.0</version>
</dependency>

1. 在FXML文件中添加节点

```xml

```

1. 编写代码

```java
public class QRCodeController {

   @FXML
   private JFXButton startButton;

   @FXML
   private ImageView imageView;

   private Webcam webcam;

   private boolean capturing;

   private void startCapture() {
       capturing = true;
       Thread captureThread = new Thread(() -> {
           while (capturing) {
               //获取摄像头数据
               BufferedImage image = webcam.getImage();
               //将图片转换为二进制流
               ByteArrayOutputStream baos = new ByteArrayOutputStream();
               try {
                   ImageIO.write(image, "jpeg", baos);
               } catch (IOException e) {
                   e.printStackTrace();
               }
               byte[] bytes = baos.toByteArray();

               //使用Zxing解码二维码
               BinaryBitmap binaryBitmap = new BinaryBitmap(new HybridBinarizer(new BufferedImageLuminanceSource(ImageIO.read(new ByteArrayInputStream(bytes)))));
               Map<DecodeHintType, Object> hints = new HashMap<>(1);
               hints.put(DecodeHintType.CHARACTER_SET, "UTF-8");
               try {
                   Result result = new MultiFormatReader().decode(binaryBitmap, hints);
                   //解码成功，更新UI
                   Platform.runLater(() -> {
                       startButton.setDisable(false);
                       capturing = false;
                       imageView.setDisable(true);
                       Alert alert = new Alert(Alert.AlertType.INFORMATION);
                       alert.setTitle("扫描结果");
                       alert.setHeaderText(null);
                       alert.setContentText(result.getText());
                       alert.showAndWait();
                   });
               } catch (NotFoundException | IOException e) {
                   //解码失败，继续扫描
                   e.printStackTrace();
               }
           }
       });
       captureThread.start();
   }

   @FXML
   public void handleStartButtonAction(ActionEvent event) {
       //开始扫描
       startButton.setDisable(true);
       imageView.setDisable(false);
       webcam = Webcam.getDefault();
       webcam.open();
       startCapture();
   }

}
```

1. 在main方法中启动JavaFX应用程序

```java
public class Main extends Application {

   @Override
   public void start(Stage primaryStage) throws Exception {
       Parent root = FXMLLoader.load(getClass().getResource("/fxml/QRCode.fxml"));
       Scene scene = new Scene(root, 400, 450);
       primaryStage.setScene(scene);
       primaryStage.setTitle("扫描二维码");
       primaryStage.show();
   }

   public static void main(String[] args) {
       launch(args);
   }

}
```

以上就是Java实现电脑端扫描二维码的两种方法。