1.依賴

        <!--QRCode-->
        <dependency>
            <groupId>com.google.zxing</groupId>
            <artifactId>core</artifactId>
            <version>3.1.0</version>
        </dependency>

2.工具類

import com.google.zxing.*;
import com.google.zxing.client.j2se.BufferedImageLuminanceSource;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.common.HybridBinarizer;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
import lombok.
 
extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
import org.springframework.web.multipart.MultipartFile;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.UUID;

@Component
@Slf4j
 
public class QRCodeUtil {
    private static final String CHARSET = "utf-8";
    private static final String FORMAT_NAME = "jpg";
    // 二維碼尺寸
    private static final int QRCODE_SIZE = 300;

    // 二維碼儲存地址
    private static String path;

    public static String getPath() {
        return path;
    }

    @Value(
 
"${file.linux.path}")
    public void setPath(String path) {
        QRCodeUtil.path = path;
    }
    /**
     * 生成二維碼
     * @param content
     * @return
     * @throws Exception
     */
    public static String createImage(String content) throws Exception {
        Hashtable<EncodeHintType, Object> hints = new Hashtable<>();
        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);
        int width = bitMatrix.getWidth();
        int height = bitMatrix.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, bitMatrix.get(x, y) ? 0xFF000000 : 0xFFFFFFFF);
            }
        }
        File files = new File(path);
        log.debug("資料夾{}",files);
        if (!files.exists()) {//目錄不存在就建立
            files.mkdirs();
        }
        String newName = UUID.randomUUID().toString();
        ImageIO.write(image, FORMAT_NAME, new File(files + File.separator + newName + "." + FORMAT_NAME));
        return path + newName + "." + FORMAT_NAME;
    }
    public static String readImage(MultipartFile file) throws Exception {
        MultiFormatReader formatReader = new MultiFormatReader();
        BufferedImage image = ImageIO.read(file.getInputStream());
        BinaryBitmap binaryBitmap = new BinaryBitmap(new HybridBinarizer(new BufferedImageLuminanceSource(image)));
        HashMap hints = new HashMap();
        hints.put(EncodeHintType.CHARACTER_SET, CHARSET);
        hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
        hints.put(EncodeHintType.MARGIN, 1);
        Result result = formatReader.decode(binaryBitmap,hints);
        return result.getText();
    }
}