Top 21 Techblog

Generating QR Codes in Java with ZXing

The following code snipped gives you a ready to use Java method for generating QR Codes. For this example we used ZXing-1.5.

/**
     * Call this method to create a QR-code image. You must provide the OutputStream where the image data can be written.
     * 
     * @param outputStream The OutputStream where the QR-code image data is written.
     * @param content The string that should be encoded with the QR-code.
     * @param qrCodeSize The QR-code must be quadratic. So this is the number of pixel in width and height.
     * @param imageFormat The image format in which the image should be rendered. As Example 'png' or 'jpg'. See @javax.imageio.ImageIO for
     *        more information which image formats are supported.
     * @throws Exception If an Exception occur during the create of the QR-code or while writing the data into the OutputStream.
     */
    public void createQrCode(OutputStream outputStream, String content, int qrCodeSize, String imageFormat) throws SolseitException
    {
        try
        {
            // Create the ByteMatrix for the QR-Code that encodes the given String.

            Hashtable<EncodeHintType, ErrorCorrectionLevel> hintMap = new Hashtable<EncodeHintType, ErrorCorrectionLevel>();
            hintMap.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);

            QRCodeWriter qrCodeWriter = new QRCodeWriter();
            ByteMatrix byteMatrix = qrCodeWriter.encode(content, BarcodeFormat.QR_CODE, qrCodeSize, qrCodeSize, hintMap);

            // Make the BufferedImage that are to hold the QRCode

            int matrixWidth = byteMatrix.getWidth();

            BufferedImage image = new BufferedImage(matrixWidth, matrixWidth, BufferedImage.TYPE_INT_RGB);
            image.createGraphics();

            Graphics2D graphics = (Graphics2D) image.getGraphics();
            graphics.setColor(Color.WHITE);
            graphics.fillRect(0, 0, matrixWidth, matrixWidth);

            // Paint and save the image using the ByteMatrix

            graphics.setColor(Color.BLACK);

            for (int i = 0; i < matrixWidth; i++)
            {
                for (int j = 0; j < matrixWidth; j++)
                {
                    if (byteMatrix.get(i, j) == 0)
                    {
                        graphics.fillRect(i, j, 1, 1);
                    }
                }
            }

            ImageIO.write(image, imageFormat, outputStream);
        }
        catch (Exception ex)
        {
            ...
        }
    }

You can download the latest version of the library on the ZXing download site.