Java工具类把URL转换成二维码

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

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
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;

public class CodeUtil {

    private static final int BLACK = 0xFF000000;
    private static final int WHITE = 0xFFFFFFFF;

    public static String createQrCode(String url, String path, String fileName) {
        try {
            Map<EncodeHintType, String> hints = new HashMap<>();
            hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
            BitMatrix bitMatrix = new MultiFormatWriter().encode(url, 
                BarcodeFormat.QR_CODE, 400, 400, hints);
            File file = new File(path, fileName);
            if (file.exists() 
                || ((file.getParentFile().exists() 
                || file.getParentFile().mkdirs()) && file.createNewFile())) {
                writeToFile(bitMatrix, "jpg", file);
                return file.toString();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
 
    static void writeToFile(BitMatrix matrix, String format, File file) 
                throws IOException {
        BufferedImage image = toBufferedImage(matrix);
        if (!ImageIO.write(image, format, file)) {
            throw new IOException("Could not write an image of format " 
                + format + " to " + file);
        }
    }
 
    static void writeToStream(BitMatrix matrix, String format, OutputStream stream) 
                throws IOException {
        BufferedImage image = toBufferedImage(matrix);
        if (!ImageIO.write(image, format, stream)) {
            throw new IOException("Could not write an image of format " + format);
        }
    }
 
    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) ? BLACK : WHITE);
            }
        }
        return image;
    }

    public static void main(String[] args) {
        createQrCode("www.baidu.com","D:\\","code.jpg");
    }

}

参考：把url链接转换成二维码的工具类