Java后台直接生成二维码介绍

Java后台直接生成二维码

1、其实jquery也可以直接生成二维码的，但我测试的时候，二维码生成后太模糊，难以识别。所以在这里介绍在后来生成二维码的方式。

2、不善于文字描述，直接上代码了。

import java.awt.Graphics2D;import java.awt.geom.AffineTransform;import java.awt.image.BufferedImage;import java.io.File;import java.io.IOException;import java.io.OutputStream;import java.util.HashMap;import java.util.Hashtable;import java.util.Map;import javax.imageio.ImageIO;import javax.servlet.http.HttpServletResponse;import org.slf4j.Logger;import org.slf4j.LoggerFactory;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 com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;/** * <p>Title:QRCodeUtil </p> * <p>Description: 二维码生成工具类</p> * @author Administrator * @version  * @since  */public final class QRCodeUtil extends LuminanceSource {    private static final Logger logger = LoggerFactory.getLogger(QRCodeUtil.class);    // 二维码颜色    private static final int BLACK = 0xFF000000;    // 二维码颜色    private static final int WHITE = 0xFFFFFFFF;    private final BufferedImage image;    private final int left;    private final int top;    public QRCodeUtil(BufferedImage image) {        this(image, 0, 0, image.getWidth(), image.getHeight());    }    public QRCodeUtil(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 QRCodeUtil(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 QRCodeUtil(rotatedImage, top, sourceWidth - (left + width), getHeight(), width);    }    /**     * @param matrix     * @return     */    private 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;    }    /**     * 生成二维码图片     *      * @param matrix     * @param format     * @param file     * @throws IOException     */    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);        }    }    /**     * 生成二维码图片流     *      * @param matrix     * @param format     * @param stream     * @throws IOException     */    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);        }    }    /**     * 根据内容，生成指定宽高、指定格式的二维码图片     *     * @param text   内容     * @param width  宽     * @param height 高     * @param format 图片格式     * @return 生成的二维码图片路径     * @throws Exception     */    private static String generateQRCode(String text, int width, int height, String format, String pathName)            throws Exception {        Hashtable<EncodeHintType, Object> hints = new Hashtable<EncodeHintType, Object>();        hints.put(EncodeHintType.CHARACTER_SET, "utf-8");// 指定编码格式        hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);// 指定纠错等级        hints.put(EncodeHintType.MARGIN, 1); // 白边大小，取值范围0~4        BitMatrix bitMatrix = new MultiFormatWriter().encode(text, BarcodeFormat.QR_CODE, width, height, hints);        File outputFile = new File(pathName);        writeToFile(bitMatrix, format, outputFile);        return pathName;    }    /**     * 输出二维码图片流     *      * @param text 二维码内容     * @param width 二维码宽     * @param height 二维码高     * @param format 图片格式eg: png, jpg, gif     * @param response HttpServletResponse     * @throws Exception     */    public static void generateQRCode(String text, int width, int height, String format, HttpServletResponse response)            throws Exception {        Hashtable<EncodeHintType, Object> hints = new Hashtable<EncodeHintType, Object>();        hints.put(EncodeHintType.CHARACTER_SET, "utf-8");// 指定编码格式        hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);// 指定纠错等级        hints.put(EncodeHintType.MARGIN, 1); // 白边大小，取值范围0~4        BitMatrix bitMatrix = new MultiFormatWriter().encode(text, BarcodeFormat.QR_CODE, width, height, hints);        writeToStream(bitMatrix, format, response.getOutputStream());    }    /**     * 解析指定路径下的二维码图片     *     * @param filePath 二维码图片路径     * @return     */    public static String parseQRCode(String filePath) {        String content = "";        try {            File file = new File(filePath);            BufferedImage image = ImageIO.read(file);            LuminanceSource source = new QRCodeUtil(image);            Binarizer binarizer = new HybridBinarizer(source);            BinaryBitmap binaryBitmap = new BinaryBitmap(binarizer);            Map<DecodeHintType, Object> hints = new HashMap<DecodeHintType, Object>();            hints.put(DecodeHintType.CHARACTER_SET, "UTF-8");            MultiFormatReader formatReader = new MultiFormatReader();            Result result = formatReader.decode(binaryBitmap, hints);            logger.info("result 为：" + result.toString());            logger.info("resultFormat 为：" + result.getBarcodeFormat());            logger.info("resultText 为：" + result.getText());            // 设置返回值            content = result.getText();        } catch (Exception e) {            logger.error(e.getMessage());        }        return content;    }    public static void main(String[] args) {        String text = "hello world!"; // 随机生成验证码        System.out.println("随机码： " + text);        int width = 100; // 二维码图片的宽        int height = 100; // 二维码图片的高        String format = "png"; // 二维码图片的格式        try {            // 生成二维码图片，并返回图片路径            String pathName = generateQRCode(text, width, height, format, "D:/new.png");            System.out.println("生成二维码的图片路径： " + pathName);            String content = parseQRCode(pathName);            System.out.println("解析出二维码的图片的内容为： " + content);        } catch (Exception e) {            e.printStackTrace();        }    }}

<dependency><groupId>com.google.zxing</groupId><artifactId>core</artifactId><version>3.3.0</version></dependency>