springboot二维码生成

可以使用第三方库Zxing来生成二维码。首先需要在pom.xml中添加以下依赖：

<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>

然后可以使用以下代码生成二维码：

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

import javax.imageio.ImageIO;

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;

public class QRCodeGenerator {

    public static void main(String[] args) {
        String text = "https://www.baidu.com/";
        int width = 300;
        int height = 300;
        String format = "png";
        Map<EncodeHintType, Object> hints = new HashMap<>();
        hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
        try {
            BitMatrix bitMatrix = new QRCodeWriter().encode(text, BarcodeFormat.QR_CODE, width, height, hints);
            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);
                }
            }
            File outputFile = new File("qrcode.png");
            ImageIO.write(image, format, outputFile);
        } catch (WriterException | IOException e) {
            e.printStackTrace();
        }
    }

}