如今二维码这么流行的时刻。也必须知道二维码是怎么生成。如今我们就来看看，是怎么生成的。
事实上主要是利用goggle公布的jar来使用：本文转自
1、二维码的生成
将 包增加到classpath下。
二维码的生成须要借助MatrixToImageWriter类，该类是由Google提供的，能够将该类复制到源代码中。这里我将该类的源代码贴上，能够直接使用。
直接能够生成二维码的代码
public void test1() throws Exception{ String content = "www.baidu.com"; String path = "d://"; MultiFormatWriter multiFormatWriter = new MultiFormatWriter();//Zxing是Google提供的关于条码 Map hints = new HashMap(); hints.put(EncodeHintType.CHARACTER_SET, "UTF-8"); BitMatrix bitMatrix = multiFormatWriter.encode(content, BarcodeFormat.QR_CODE, 400, 400,hints);//这里是照片的大小 File file1 = new File(path,"my.jpg"); MatrixToImageWriter.writeToFile(bitMatrix, "jpg", file1); System.out.println("运行完成"); } 当我们能发现，这个代码拷贝上后发现有一个 MatrixToImageWriter报错，所以须要我们去找。可是这里我贴出代码，能够直接使用。
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); } } }
如今就能够d盘的根文件夹下载看生成的二维码了
二维码解析
和生成一样，我们须要一个辅助类（ BufferedImageLuminanceSource），相同该类Google也提供了，这里我相同将该类的源代码贴出来，能够直接拷贝使用个，省去查找的麻烦
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, 0xFFFFFFFF); // = 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); } } 解析二维码的代码
MultiFormatReader formatReader = new MultiFormatReader(); String filePath = "图片的路径"; 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(); } 如今这样能够在控制台看到二维码的内容。
纯粹是笔记。