Java中基于maven实现zxing二维码功能

下面我将提供一个完整的攻略，教你如何在Java中基于maven实现zxing二维码功能。

1. 环境准备

首先需要安装Maven，同时在pom.xml中添加以下依赖：

<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>

然后在代码中引入zxing二维码库，例如：

import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.WriterException;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.QRCodeWriter;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

2. 生成二维码

首先，需要创建一个QRCodeWriter对象，然后使用这个对象将文本生成一个二维码。可以通过下面的代码获取一个二维码图片的BufferedImage对象：

try {  
   Map<EncodeHintType, Object> hints = new HashMap<EncodeHintType, Object>();  
   hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
   hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);  
   QRCodeWriter writer = new QRCodeWriter();  
   BitMatrix bitMatrix = writer.encode("www.example.com", BarcodeFormat.QR_CODE, 200, 200, hints);  
   BufferedImage image = new BufferedImage(200, 200, BufferedImage.TYPE_INT_RGB);
   for (int x = 0; x < 200; x++) {
       for (int y = 0; y < 200; y++) {
           image.setRGB(x, y, bitMatrix.get(x, y) ? Color.BLACK.getRGB() : Color.WHITE.getRGB());
       }
   }
   File qrFile = new File("qrcode.png");
   ImageIO.write(image, "png", qrFile);
} catch (WriterException e) {  
   e.printStackTrace();  
} catch (IOException e) {  
   e.printStackTrace();  
}

上面这个例子中，我使用了UTF-8编码和纠错等级L。如果你需要更高的纠错等级，可以改为ErrorCorrectionLevel.H。

3. 解析二维码

接下来，我们看一下如何解析一个二维码。首先，需要创建一个MultiFormatReader对象，然后通过这个对象将一个二维码解析为一个字符串。可以使用下面的代码：

try {
   File qrFile = new File("qrcode.png");
   BufferedImage image = ImageIO.read(qrFile);
   Map<DecodeHintType, Object> hints = new HashMap<DecodeHintType, Object>();  
   hints.put(DecodeHintType.CHARACTER_SET, "UTF-8");
   hints.put(DecodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);  
   MultiFormatReader reader = new MultiFormatReader();  
   Result result = reader.decode(new BinaryBitmap(new HybridBinarizer(new BufferedImageLuminanceSource(image))), hints);  
   System.out.println(result.getText());
} catch (NotFoundException e) {  
   e.printStackTrace();  
} catch (IOException e) {  
   e.printStackTrace();  
}

上面这个例子中，我设置了相同的编码和纠错等级，然后使用MultiFormatReader对象的decode方法解析二维码。我们可以在控制台中打印出二维码的内容。

4. 示例应用

除此之外，我们也可以将这个二维码生成和解析的程序封装成一个简单的示例应用。例如，我们可以创建一个控制台应用，让用户选择生成二维码还是解析二维码。具体代码参考下面的示例：

import com.google.zxing.BarcodeFormat;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatReader;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.Result;
import com.google.zxing.WriterException;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.common.HybridBinarizer;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

public class QrCodeApp {

    public static void main(String[] args) {
        System.out.println("Please select an option:");
        System.out.println("1. Generate QR Code");
        System.out.println("2. Parse QR Code");
        Scanner scanner = new Scanner(System.in);
        int option = scanner.nextInt();
        if (option == 1) {
            generateQrCode();
        } else if (option == 2) {
            parseQrCode();
        } else {
            System.out.println("Invalid option.");
        }
    }

    private static void generateQrCode() {
        try {
            System.out.print("Enter text to encode: ");
            Scanner scanner = new Scanner(System.in);
            String textToEncode = scanner.nextLine();
            Map<EncodeHintType, Object> hints = new HashMap<>();
            hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
            hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);
            QRCodeWriter writer = new QRCodeWriter();
            BitMatrix bitMatrix = writer.encode(textToEncode, BarcodeFormat.QR_CODE, 200, 200, hints);
            BufferedImage image = new BufferedImage(200, 200, BufferedImage.TYPE_INT_RGB);
            for (int x = 0; x < 200; x++) {
                for (int y = 0; y < 200; y++) {
                    image.setRGB(x, y, bitMatrix.get(x, y) ? Color.BLACK.getRGB() : Color.WHITE.getRGB());
                }
            }
            File qrFile = new File("qrcode.png");
            ImageIO.write(image, "png", qrFile);
            System.out.println("QR Code generated.");
        } catch (WriterException | IOException e) {
            e.printStackTrace();
        }
    }

    private static void parseQrCode() {
        try {
            System.out.print("Enter path to QR Code image file: ");
            Scanner scanner = new Scanner(System.in);
            String imagePath = scanner.nextLine();
            File qrFile = new File(imagePath);
            BufferedImage image = ImageIO.read(qrFile);
            MultiFormatReader reader = new MultiFormatReader();
            Result result = reader.decode(new BinaryBitmap(new HybridBinarizer(new BufferedImageLuminanceSource(image))), null);
            System.out.println("QR Code content: " + result.getText());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

该应用程序通过控制台接收输入，用户可以选择生成二维码还是解析二维码。

以上就是关于在Java中基于maven实现zxing二维码功能的完整攻略了，希望能对你有所帮助。