二维码生成工具——谷歌zxing

<dependencies>

    <dependency>
      <groupId>com.google.zxinggroupId>
      <artifactId>coreartifactId>
      <version>3.4.0version>
    dependency>
    <dependency>
      <groupId>com.google.zxinggroupId>
      <artifactId>javaseartifactId>
      <version>3.4.0version>
    dependency>

    ......

dependencies>

public class QRCodeUtil {

    //二维码宽度，单位像素
    private static final int CODE_WIDTH = 400;
    //二维码高度，单位像素
    private static final int CODE_HEIGHT = 400;
    //二维码图片格式
    private static final String FORMAT = "jpg";
    //编码格式
    private static final String CHARSET = "UTF-8";
    //默认二维码文件夹路径
    private static final String DEFAULT_FILE_DIR = "E:/tmp/qrcode/";

    //二维码参数
    private static Map hints = new HashMap();

    static{
        //设置字符编码类型
        hints.put(EncodeHintType.CHARACTER_SET, CHARSET);
        //设置纠错等级L/M/Q/H，纠错等级越高越不易识别，当前设置等级为最高等级H
        hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.M);
        //设置二维码边距，单位像素，值越小二维码距离四周越近
        hints.put(EncodeHintType.MARGIN, 1);
    }

    //------------------------------生成二维码------------------------------

    /**
     * 生成二维码，写入文件
     * @param codeContent 二维码内容
     * @param fileName 文件名称
     * @return
     */
    public static String createQRFile(String codeContent, String fileName) throws Exception {
        File file = new File(DEFAULT_FILE_DIR, fileName + "." + FORMAT);
        //生成并保存二维码图片文件
        BitMatrix bitMatrix = new MultiFormatWriter().encode(codeContent, BarcodeFormat.QR_CODE, CODE_WIDTH, CODE_HEIGHT, hints);
        MatrixToImageWriter.writeToPath(bitMatrix, FORMAT, file.toPath());
        return file.getPath();
    }

    /**
     * 生成二维码，写入输出流（例如：response.getOutputStream()）
     * @param codeContent 二维码内容
     * @param out 输出流
     */
    public static void createQROutput(String codeContent, OutputStream out) throws Exception {
        BitMatrix bitMatrix = new MultiFormatWriter().encode(codeContent, BarcodeFormat.QR_CODE, CODE_WIDTH, CODE_HEIGHT, hints);
        MatrixToImageWriter.writeToStream(bitMatrix, FORMAT, out);
    }

    //------------------------------解析二维码------------------------------

    /**
     * 解析二维码文件
     * @param filePath 文件路径
     * @return
     */
    public static String parseQRFile(String filePath) throws Exception {
        File file = new File(filePath);
        if (file == null || !file.exists() || file.isDirectory()) {
            return null;
        }
        BufferedImage bufferedImage = ImageIO.read(file);
        BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(new BufferedImageLuminanceSource(bufferedImage)));
        Hashtable hints = new Hashtable();
        hints.put(DecodeHintType.CHARACTER_SET, CHARSET);
        Result result = new MultiFormatReader().decode(bitmap, hints);
        return result.getText();
    }

    /**
     * 解析网络URL二维码
     * @param urlPath 二维码图片网络地址
     * @return
     */
    public static String parseQRUrl(String urlPath) throws Exception {
        URL url = new URL(urlPath);
        BufferedImage bufferedImage = ImageIO.read(url);
        BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(new BufferedImageLuminanceSource(bufferedImage)));
        Hashtable hints = new Hashtable();
        hints.put(DecodeHintType.CHARACTER_SET, CHARSET);
        Result result = new MultiFormatReader().decode(bitmap, hints);
        return result.getText();
    }

}