springboot 批量生成二维码

可以使用Google开源的Zxing库来生成二维码，以下是基于Spring Boot的批量生成二维码的示例代码：

1. 引入依赖

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>

2. 编写生成二维码的工具类

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

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 QrCodeUtils {

    private static final int WIDTH = 300; // 二维码宽度
    private static final int HEIGHT = 300; // 二维码高度
    private static final String FORMAT = "png"; // 二维码格式
    private static final String CHARSET = "UTF-8"; // 字符集
    private static final int MARGIN = 1; // 边距

    /**
     * 生成二维码
     * 
     * @param content 二维码内容
     * @param file    二维码文件
     * @throws Exception
     */
    public static void generateQRCode(String content, File file) throws Exception {
        BitMatrix bitMatrix = new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE, WIDTH, HEIGHT,
                getDecodeHintType());
        BufferedImage image = toBufferedImage(bitMatrix);
        ImageIO.write(image, FORMAT, file);
    }

    /**
     * 批量生成二维码
     * 
     * @param contents 二维码内容列表
     * @param dir      二维码目录
     * @throws Exception
     */
    public static void batchGenerateQRCode(List<String> contents, File dir) throws Exception {
        if (!dir.exists()) {
            dir.mkdirs();
        }

        for (int i = 0; i < contents.size(); i++) {
            String content = contents.get(i);
            String fileName = "qrcode_" + (i + 1) + "." + FORMAT;
            File file = new File(dir, fileName);
            generateQRCode(content, file);
        }
    }

    /**
     * 获取编码提示类型
     * 
     * @return
     */
    private static EncodeHintType getDecodeHintType() {
        EncodeHintType encodeHintType = EncodeHintType.ERROR_CORRECTION;
        ErrorCorrectionLevel errorCorrectionLevel = ErrorCorrectionLevel.H;
        return encodeHintType;
    }

    /**
     * BitMatrix转BufferedImage
     * 
     * @param matrix
     * @return
     */
    private static BufferedImage toBufferedImage(BitMatrix matrix) {
        int width = matrix.getWidth();
        int height = matrix.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, matrix.get(x, y) ? 0xFF000000 : 0xFFFFFFFF);
            }
        }
        return image;
    }

}

3. 调用工具类批量生成二维码

import java.io.File;
import java.util.ArrayList;
import java.util.List;

public class QrCodeTest {

    public static void main(String[] args) throws Exception {
        List<String> contents = new ArrayList<>();
        contents.add("http://www.baidu.com");
        contents.add("http://www.google.com");
        contents.add("http://www.github.com");

        File dir = new File("D:/qrcode");
        QrCodeUtils.batchGenerateQRCode(contents, dir);
    }

}

以上代码会在D:/qrcode目录下生成三个二维码文件，内容分别为http://www.baidu.com、http://www.google.com、http://www.github.com。