java生成二维码

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使用Google开源库zxing生成二维码

  1. 在pom.xml文件中添加以下依赖：

    <dependency>
    <groupId>com.google.zxing</groupId>
    <artifactId>core</artifactId>
    <version>2.1</version>
</dependency>
<dependency>
    <groupId>com.google.zxing</groupId>
    <artifactId>javase</artifactId>
    <version>2.1</version>
</dependency>

  2. 生成二维码，并将logo嵌入

    private static byte[] createQRCode(String url) throws Exception {

    QRCodeWriter writer = new QRCodeWriter();
HashMap<EncodeHintType, Object> m = new HashMap<EncodeHintType, Object>();
m.put(EncodeHintType.CHARACTER_SET, com.tencent.jungle.quntribe.helper.CommonUtil.UTF8);

// 按最大尺寸生成
BitMatrix bm = writer.encode(url, BarcodeFormat.QR_CODE, 600, 600, m);
MatrixToImageConfig config = new MatrixToImageConfig(BufferedImage.TYPE_INT_RGB, MatrixToImageConfig.WHITE);
BufferedImage image = MatrixToImageWriter.toBufferedImage(bm, config);
Graphics2D m2 = image.createGraphics();
BufferedImage overlay = ImageIO.read(new URL(BULUO_LOGO_IMAGE)/*new File("D://Penguins.jpg")*/);
int deltaHeight = image.getHeight() - overlay.getHeight();
int deltaWidth = image.getWidth()  - overlay.getWidth();

m2.drawImage(image, 0, 0, null);
m2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 1f));
m2.setColor(Color.WHITE);
m2.drawImage(overlay, (int) Math.round(deltaWidth / 2),
        (int) Math.round(deltaHeight / 2), null);

m2.dispose();

ByteArrayOutputStream buffer = new ByteArrayOutputStream(512);
ImageIO.write(image, "png", buffer);
return buffer.toByteArray();

    }
    ‘
    这里有几个点需要注意：

  • 构造函数要使用可以指定颜色区间的：(否则会导致产生黑白的图片)
    MatrixToImageConfig config = new MatrixToImageConfig(BufferedImage.TYPE_INT_RGB, MatrixToImageConfig.WHITE);
  • setComposite设置对应位置关系，要使用AlphaComposite.SRC_OVER，这样，logo才不会被后面的二维码所覆盖
    参见：Compositing Graphics