springboot 生成二维码

你可以使用第三方库生成二维码，比如zxing或者google的qrcode库。以下是使用zxing生成二维码的示例代码：

1. 添加依赖

<dependency>
    <groupId>com.google.zxing</groupId>
    <artifactId>core</artifactId>
    <version>3.4.0</version>
</dependency>
<dependency>
    <groupId>com.google.zxing</groupId>
    <artifactId>javase</artifactId>
    <version>3.4.0</version>
</dependency>

2. 编写生成二维码的代码

import java.io.File;
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.MultiFormatWriter;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;

public class QRCodeGenerator {
    
    private static final String CHARSET = "utf-8";
    private static final String FORMAT_NAME = "JPG";
    private static final int QRCODE_SIZE = 300;
    private static final int WIDTH = 60;
    private static final int HEIGHT = 60;

    private static void createImage(String content, String imgPath) throws Exception {
        Map<EncodeHintType, Object> hints = new HashMap<EncodeHintType, Object>();
        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);
        File outputFile = new File(imgPath);
        MatrixToImageWriter.writeToFile(bitMatrix, FORMAT_NAME, outputFile);
    }

    public static void main(String[] args) throws Exception {
        String content = "https://www.baidu.com"; // 二维码内容
        String imgPath = "C:/Users/Administrator/Desktop/qrcode.jpg"; // 生成的二维码图片路径
        createImage(content, imgPath);
    }
}

运行代码后，会在指定的路径生成一个二维码图片。