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：本文转自点击打开链接

1、二维码的生成

将Zxing-core.jar 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。