Zxing is a parsing tool about barcodes (one-R code, QR code) provided by Google. It provides methods for generating and analyzing QR codes. Now I will briefly introduce the use of Java to generate and analyze QR codes using Zxing.
1. Generation of QR code
1.1 Add the Zxing-core.jar package to classpath.
1.2 The generation of QR code requires the help of the MatrixToImageWriter class. This class is provided by Google. You can copy the class to the source code. Here I paste the source code of this class and can be used directly.
import com.google.zxing.common.BitMatrix; import javax.imageio.ImageIO; import java.io.File; import java.io.OutputStream; import java.io.IOException; import java.awt.image.BufferedImage; public final class MatrixToImageWriter { private static final int BLACK = 0xFF000000; private static final int WHITE = 0xFFFFFFFF; private MatrixToImageWriter() {} public 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 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); } } public 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); } } }1.3 Write implementation code that generates QR code
try { String content = "120605181003;http://www.cnblogs.com/jtmjx"; String path = "C:/Users/Administrator/Desktop/testImage"; MultiFormatWriter multiFormatWriter = new MultiFormatWriter(); Map hints = new HashMap(); hints.put(EncodeHintType.CHARACTER_SET, "UTF-8"); BitMatrix bitMatrix = multiFormatWriter.encode(content, BarcodeFormat.QR_CODE, 400, 400,hints); File file1 = new File(path,"Nambeginner.jpg"); MatrixToImageWriter.writeToFile(bitMatrix, "jpg", file1); } catch (Exception e) { e.printStackTrace(); }Now after running, you can generate a QR code picture. Isn’t it very simple? Next, let's take a look at how to parse the QR code
2. Analysis of QR code
2.1 Add the Zxing-core.jar package to classpath.
2.2 Like generation, we need a auxiliary class (BufferedImageLuminanceSource), which is also provided by Google. Here I also paste the source code of this class and can copy and use it directly, saving the trouble of searching.
BufferedImageLuminanceSource import com.google.zxing.LuminanceSource; import java.awt.Graphics2D; import java.awt.geom.AffineTransform; import java.awt.image.BufferedImage; public final class BufferedImageLuminanceSource extends LuminanceSource { private final BufferedImage image; private final int left; private final int top; public BufferedImageLuminanceSource(BufferedImage image) { this(image, 0, 0, image.getWidth(), image.getHeight()); } public BufferedImageLuminanceSource(BufferedImage image, int left, int top, int width, int height) { super(width, height); int sourceWidth = image.getWidth(); int sourceHeight = image.getHeight(); if (left + width > sourceWidth || top + height > sourceHeight) { throw new IllegalArgumentException("Crop rectangle does not fit within image data."); } for (int y = top; y < top + height; y++) { for (int x = left; x < left + width; x++) { if ((image.getRGB(x, y) & 0xFF000000) == 0) { image.setRGB(x, y, 0xFFFFFFF); // = white } } } this.image = new BufferedImage(sourceWidth, sourceHeight, BufferedImage.TYPE_BYTE_GRAY); this.image.getGraphics().drawImage(image, 0, 0, null); this.left = left; this.top = top; } @Override public byte[] getRow(int y, byte[] row) { if (y < 0 || y >= getHeight()) { throw new IllegalArgumentException("Requested row is outside the image: " + y); } int width = getWidth(); if (row == null || row.length < width) { row = new byte[width]; } image.getRaster().getDataElements(left, top + y, width, 1, row); return row; } @Override public byte[] getMatrix() { int width = getWidth(); int height = getHeight(); int area = width * height; byte[] matrix = new byte[area]; image.getRaster().getDataElements(left, top, width, height, matrix); return matrix; } @Override public boolean isCropSupported() { return true; } @Override public LuminanceSource crop(int left, int top, int width, int height) { return new BufferedImageLuminanceSource(image, this.left + left, this.top + top, width, height); } @Override public boolean isRotateSupported() { return true; } @Override public LuminanceSource rotateCounterClockwise() { int sourceWidth = image.getWidth(); int sourceHeight = image.getHeight(); AffineTransform transform = new AffineTransform(0.0, -1.0, 1.0, 0.0, 0.0, sourceWidth); BufferedImage rotatedImage = new BufferedImage(sourceHeight, sourceWidth, BufferedImage.TYPE_BYTE_GRAY); Graphics2D g = rotatedImage.createGraphics(); g.drawImage(image, transform, null); g.dispose(); int width = getWidth(); return new BufferedImageLuminanceSource(rotatedImage, top, sourceWidth - (left + width), getHeight(), width); } }2.3 Write implementation code that parses QR code
try { MultiFormatReader formatReader = new MultiFormatReader(); String filePath = "C:/Users/Administrator/Desktop/testImage/test.jpg"; File file = new File(filePath); BufferedImage image = ImageIO.read(file);; LuminanceSource source = new BufferedImageLuminanceSource(image); Binarizer binarizer = new HybridBinarizer(source); BinaryBitmap binaryBitmap = new BinaryBitmap(binarizer); Map hints = new HashMap(); hints.put(EncodeHintType.CHARACTER_SET, "UTF-8"); Result result = formatReader.decode(binaryBitmap,hints); System.out.println("result = "+ result.toString()); System.out.println("resultFormat = "+ result.getBarcodeFormat()); System.out.println("resultText = "+ result.getText()); } catch (Exception e) { e.printStackTrace(); }Now after running, you can see that the console prints the content of the QR code.
So far, Zxing used Zxing to generate and parse the QR code and the demonstration was completed, mainly making memos for yourself, and at the same time making convenience for those in need. hehe!
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