java生成二维码、条形码和二维码、条形码的解码

首先，使用java生成二维码和条形码需要ZXing

ZXing是一个开源Java类库用于解析多种格式的条形码和二维码.

官网：http://code.google.com/p/zxing/

MatrixToImageWriter类辅助生成二维码，该类是由Google提供的，我们可以把它复制到自己的项目中使用：

下面是MatrixToImageWriter类的源代码：

package learn;import java.awt.image.BufferedImage;import java.io.File;import java.io.IOException;import java.io.OutputStream;import javax.imageio.ImageIO;import com.google.zxing.common.BitMatrix;public class WriteBitMatricToFile {private static final int BLACK = 0xFF000000;private static final int WHITE = 0xFFFFFFFF;private static BufferedImage toBufferedImage(BitMatrix bm) {int width = bm.getWidth();int height = bm.getHeight();BufferedImage image = new BufferedImage(width, height,        BufferedImage.TYPE_3BYTE_BGR);for (int i = 0; i < width; i++) {for (int j = 0; j < height; j++) {image.setRGB(i, j, bm.get(i, j) ? BLACK : WHITE);}}return image;}public static void writeBitMatricToFile(BitMatrix bm, String format,        File file) {BufferedImage image = toBufferedImage(bm);try {if (!ImageIO.write(image, format, file)) {throw new RuntimeException("Can not write an image to file" + file);}} catch (IOException e) {e.printStackTrace();}}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);}}}

生成二维码和条形码的格式不同，二维码的编码格式是二维码的格式是BarcodeFormat.QR_CODE，条形码的编码格式是条形码的格式是 BarcodeFormat.EAN_13 ，下面是源代码：

package learn;import java.io.File;import java.util.HashMap;import com.google.zxing.BarcodeFormat;import com.google.zxing.EncodeHintType;import com.google.zxing.MultiFormatWriter;import com.google.zxing.common.BitMatrix;public class EncodeTest {public static void main(String[] args) throws Exception {int width = 300;int height = 300;// int width = 105;// int height = 50;// 条形码的输入是13位的数字// String text = "6923450657713";// 二维码的输入是字符串String text = "testtesttest生成条形码图片";String format = "png";HashMap<EncodeHintType, String> hints = new HashMap<>();hints.put(EncodeHintType.CHARACTER_SET, "utf-8");// 条形码的格式是 BarcodeFormat.EAN_13// 二维码的格式是BarcodeFormat.QR_CODEBitMatrix bm = new MultiFormatWriter().encode(text,        BarcodeFormat.QR_CODE, width, height, hints);File out = new File("new.png");// 生成条形码图片// File out = new File("ean3.png");WriteBitMatricToFile.writeBitMatricToFile(bm, format, out);}}

以下是生成的二维码和条形码：

条形码的输入是6923450657713

解码的过程就是二值化使用Binarizer实现，一维码使用getBlackRow方法，二维码的使用getBlackMatrix方法。Binarizer有两个生成类，GlobalHistogramBinarizer和HybridBinarizer；这两个类对getBlackMatrix方法的实现有不同，但使用时都是一样的没什么分别。

如果对解码过程感兴趣的话，可以阅读：http://blog.csdn.net/mihenyinghua/article/details/17224019

解码时需要zxing-j2se.jar，将jar添加到classpath下。

package learn;import java.awt.image.BufferedImage;import java.io.File;import java.io.FileInputStream;import java.util.HashMap;import java.util.Map;import javax.imageio.ImageIO;import com.google.zxing.BinaryBitmap;import com.google.zxing.DecodeHintType;import com.google.zxing.LuminanceSource;import com.google.zxing.MultiFormatReader;import com.google.zxing.Result;import com.google.zxing.client.j2se.BufferedImageLuminanceSource;import com.google.zxing.common.GlobalHistogramBinarizer;public class DecodeTest {public static void main(String[] args) throws Exception {// 这里可以是条形图片码或者二维码图片// 这是二维码图片BufferedImage bi = ImageIO.read(new FileInputStream(new File("new.png")));// 这是条形码图片// BufferedImage bi = ImageIO.read(new FileInputStream(new// File("ean3.png")));if (bi != null) {Map<DecodeHintType, String> hints = new HashMap<>();hints.put(DecodeHintType.CHARACTER_SET, "utf-8");LuminanceSource source = new BufferedImageLuminanceSource(bi);// 这里还可以是 BinaryBitmap bitmap = new BinaryBitmap(new// HybridBinarizer(source));BinaryBitmap bitmap = new BinaryBitmap(        new GlobalHistogramBinarizer(source));Result res = new MultiFormatReader().decode(bitmap, hints);System.out.println(res);System.out.println("decode successfully!");}}}

参考资料：http://blog.csdn.net/mihenyinghua/article/details/17224019