使用Google ZXing生成和解析二维码

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.nihaorz</groupId>
    <artifactId>zxing</artifactId>
    <version>1.0-SNAPSHOT</version>
    <dependencies>
        <dependency>
            <groupId>com.google.zxing</groupId>
            <artifactId>core</artifactId>
            <version>2.3.0</version>
        </dependency>
    </dependencies>

</project>

MatrixToImageWriter.java

import com.google.zxing.common.BitMatrix;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;

/**
 * Created by Nihaorz on 2017/5/9.
 */
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);
        }
    }
}

BufferedImageLuminanceSource.java

import com.google.zxing.LuminanceSource;

import java.awt.*;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;

/**
 * Created by Nihaorz on 2017/5/9.
 */
public 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);
    }
}

Test.java

import com.google.zxing.BarcodeFormat;
import com.google.zxing.Binarizer;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.DecodeHintType;
import com.google.zxing.EncodeHintType;
import com.google.zxing.LuminanceSource;
import com.google.zxing.MultiFormatReader;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.Result;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.common.HybridBinarizer;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileInputStream;
import java.util.HashMap;
import java.util.Random;

/**
 * Created by Nihaorz on 2017/5/9.
 */
public class Test {

    public static void main(String[] args) {
        String path = createQrcode("https://github.com/zxing/zxing");
        System.out.println("生成的二维码地址:"+path);
        String text = decodeQr(path);
        System.out.println("扫描二维码得到的文字:"+text);
    }

    public static String createQrcode(String _text){
        String qrcodeFilePath = "";
        try {
            int qrcodeWidth = 256;
            int qrcodeHeight = 256;
            String qrcodeFormat = "png";
            HashMap<EncodeHintType, String> hints = new HashMap<EncodeHintType, String>();
            hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
            BitMatrix bitMatrix = new MultiFormatWriter().encode(_text, BarcodeFormat.QR_CODE, qrcodeWidth, qrcodeHeight, hints);

            BufferedImage image = new BufferedImage(qrcodeWidth, qrcodeHeight, BufferedImage.TYPE_INT_RGB);
            Random random = new Random();
            File QrcodeFile = new File("F:\qrcode\" + random.nextInt() + "." + qrcodeFormat);
            ImageIO.write(image, qrcodeFormat, QrcodeFile);
            MatrixToImageWriter.writeToFile(bitMatrix, qrcodeFormat, QrcodeFile);
            qrcodeFilePath = QrcodeFile.getAbsolutePath();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return qrcodeFilePath;
    }

    public static String decodeQr(String filePath) {
        String retStr = "";
        if ("".equalsIgnoreCase(filePath) && filePath.length() == 0) {
            return "图片路径为空!";
        }
        try {
            BufferedImage bufferedImage = ImageIO.read(new FileInputStream(filePath));
            LuminanceSource source = new BufferedImageLuminanceSource(bufferedImage);
            Binarizer binarizer = new HybridBinarizer(source);
            BinaryBitmap bitmap = new BinaryBitmap(binarizer);
            HashMap<DecodeHintType, Object> hintTypeObjectHashMap = new HashMap<DecodeHintType, Object>();
            hintTypeObjectHashMap.put(DecodeHintType.CHARACTER_SET, "UTF-8");
            Result result = new MultiFormatReader().decode(bitmap, hintTypeObjectHashMap);
            retStr = result.getText();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return retStr;
    }

}

参考：

http://www.cnblogs.com/java-class/p/5251690.html

http://blog.csdn.net/gao36951/article/details/41148075