java实现二维码的生成与解析

二维码的生成及解析的低层实现并不简单，我们只需要知道怎么使用就可以了，参考博客：https://blog.csdn.net/jam_fanatic/article/details/82818857

1.maven中jar包引用com.google.zxing；

2.创建QRCodeUtil二维码工具类，使用谷歌提供的帮助类BufferedImageLuminanceSource绘制二维码。

　　生成二维码：QRCodeUtil.encode(编码到二维码中的内容, 嵌入二维码的图片路径, 生成的二维码的存放路径, 图片是否进行压缩);

　　解析二维码：QRCodeUtil.decode(要解析的二维码的存放路径);

　　注意事项：如果你想让别人扫描后跳转一个页面的话，直接在编码的方法里，将编码内容改为一个地址就可以了，这样别人扫描二维码后会自动跳转。二维码存的信息越多，二维码图片也就越复杂，容错率也就越低，识别率也越低，并且二维码能存的内容大小也是有限的（大概500个汉字左右）

package com.gsafety.consumer.util;

import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Shape;
import java.awt.geom.RoundRectangle2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.OutputStream;
import java.util.Hashtable;

import javax.imageio.ImageIO;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.DecodeHintType;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatReader;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.Result;
import com.google.zxing.client.j2se.BufferedImageLuminanceSource;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.common.HybridBinarizer;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;

import lombok.extern.slf4j.Slf4j;

/**
 *   二维码工具类  
 */
@Slf4j
public class QRCodeUtil {
    
    
    
    private static final String CHARSET = "utf-8";
    private static final String FORMAT_NAME = "JPG";
    // 二维码尺寸
    private static final int QRCODE_SIZE = 250;
    // LOGO宽度
    private static final int WIDTH = 50;
    // LOGO高度
    private static final int HEIGHT = 50;
    static SnowflakeIdWorker snowflakeIdWorker = new SnowflakeIdWorker(0,0);
    private static BufferedImage createImage(String content, String imgPath, boolean needCompress) throws Exception {
        Hashtable<EncodeHintType, Object> hints = new Hashtable<EncodeHintType, Object>();
        hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
        hints.put(EncodeHintType.CHARACTER_SET, CHARSET);
        hints.put(EncodeHintType.MARGIN, 0);
        BitMatrix bitMatrix = new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE, QRCODE_SIZE, QRCODE_SIZE,
                hints);
        int width = bitMatrix.getWidth();
        int height = bitMatrix.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, bitMatrix.get(x, y) ? 0xFF000000 : 0xFFFFFFFF);
            }
        }
        if (imgPath == null || "".equals(imgPath)) {
            return image;
        }
        // 插入图片
        QRCodeUtil.insertImage(image, imgPath, needCompress);
        return image;
    }
    /**
     *  插入LOGO          
     * @param source    二维码图片    
     * @param imgPath  LOGO图片地址    
     * @param needCompress   是否压缩    
     * @throws Exception    
     */
    private static void insertImage(BufferedImage source, String imgPath, boolean needCompress) throws Exception {
        File file = new File(imgPath);
        if (!file.exists()) {
            log.info("{}该文件不存在！",imgPath);
            return;
        }
        Image src = ImageIO.read(new File(imgPath));
        int width = src.getWidth(null);
        int height = src.getHeight(null);
        if (needCompress) { // 压缩LOGO
            if (width > WIDTH) {
                width = WIDTH;
            }
            if (height > HEIGHT) {
                height = HEIGHT;
            }
            Image image = src.getScaledInstance(width, height, Image.SCALE_SMOOTH);
            BufferedImage tag = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            Graphics g = tag.getGraphics();
            g.drawImage(image, 0, 0, null); // 绘制缩小后的图
            g.dispose();
            src = image;
        }
        // 插入LOGO
        Graphics2D graph = source.createGraphics();
        int x = (QRCODE_SIZE - width) / 2;
        int y = (QRCODE_SIZE - height) / 2;
//        graph.setClip(new RoundRectangle2D.Double(0, 0, width, height, 90, 90));
        graph.drawImage(src, x, y, width, height, null);
        Shape shape = new RoundRectangle2D.Float(x, y, width, width, 90,90);
//        graph.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
//        graph.setStroke(new BasicStroke(-1f));
        graph.draw(shape);
        graph.dispose();
    }

    /**
     *    
     *  生成二维码(内嵌LOGO)   
     *  @param content   内容    
     *  @param imgPath   LOGO地址   
     *  @param destPath  存放目录    
     *  @param needCompress   是否压缩LOGO    
     *  @throws Exception    
     */
    
    public static String encode(String content, String imgPath, String destPath, boolean needCompress) throws Exception {
        BufferedImage image = QRCodeUtil.createImage(content, imgPath, needCompress);
        mkdirs(destPath);
        String random = snowflakeIdWorker.nextId();
        String file = random + ".jpg";
        ImageIO.write(image, FORMAT_NAME, new File(destPath + "/" + file));
        return "/consumer_qrcode/"+file;
    }

    /**
     *  当文件夹不存在时，mkdirs会自动创建多层目录，区别于mkdir．(mkdir如果父目录不存在则会抛出异常)    
     * @author  
      * @date 2013-12-11 上午10:16:36
     * @param destPath 存放目录    
     */
    public static void mkdirs(String destPath) {
        File file = new File(destPath);
        // 当文件夹不存在时，mkdirs会自动创建多层目录，区别于mkdir．(mkdir如果父目录不存在则会抛出异常)
        if (!file.exists() && !file.isDirectory()) {
            file.mkdirs();
        }
    }

    /**
     *     
     *  生成二维码(内嵌LOGO)         
     *  @param content  内容    
     *  @param imgPath  LOGO地址     
     *  @param destPath  存储地址   
     *  @throws Exception    
     */
    public static void encode(String content, String imgPath, String destPath) throws Exception {
        QRCodeUtil.encode(content, imgPath, destPath, false);
    }

    /**
     *   
     *   生成二维码     
     *  @param content   内容    
     *  @param destPath  存储地址   
     *  @param needCompress   是否压缩LOGO    
     *  @throws Exception    
     */
    public static void encode(String content, String destPath, boolean needCompress) throws Exception {
        QRCodeUtil.encode(content, null, destPath, needCompress);
    }

    /**
     *     
     *  生成二维码  
     * @param content   内容    
     * @param destPath  存储地址    
     * @throws Exception    
     */
    public static void encode(String content, String destPath) throws Exception {
        QRCodeUtil.encode(content, null, destPath, false);
    }

    /**
     *     
     *   生成二维码(内嵌LOGO)     
     *  @param content  内容     
     *  @param imgPath  LOGO地址    
     *  @param output   输出流    
     *  @param needCompress  是否压缩LOGO    
     *  @throws Exception    
     */
    public static void encode(String content, String imgPath, OutputStream output, boolean needCompress)
            throws Exception {
        BufferedImage image = QRCodeUtil.createImage(content, imgPath, needCompress);
        ImageIO.write(image, FORMAT_NAME, output);
    }

    /**
     *    
     *  生成二维码    
     *  @param content  内容    
     *  @param output   输出流
     *  @throws Exception    
     */
    public static void encode(String content, OutputStream output) throws Exception {
        QRCodeUtil.encode(content, null, output, false);
    }

    /**
     *     
     *   解析二维码     
     *   @param file 二维码图片     
     *   @return    
     *   @throws
     * Exception    
     */
    public static String decode(File file) throws Exception {
        BufferedImage image;
        image = ImageIO.read(file);
        if (image == null) {
            return null;
        }
        BufferedImageLuminanceSource source = new BufferedImageLuminanceSource(image);
        BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
        Result result;
        Hashtable<DecodeHintType, Object> hints = new Hashtable<DecodeHintType, Object>();
        // 解码设置编码方式为：utf-8，
        hints.put(DecodeHintType.CHARACTER_SET, CHARSET);
        //优化精度
        hints.put(DecodeHintType.TRY_HARDER, Boolean.TRUE);
        //复杂模式，开启PURE_BARCODE模式
        hints.put(DecodeHintType.PURE_BARCODE, Boolean.TRUE);
        result = new MultiFormatReader().decode(bitmap, hints);
        
        String resultStr = result.getText();
        return resultStr;
    }

    /**
     *    
     * 
     *  解析二维码      
     * @param   path   二维码图片地址    
     * @return    
     * @throws  Exception    
     */
    public static String decode(String path) throws Exception {
        return QRCodeUtil.decode(new File(path));
    }
    
    public static void main(String[] args) throws Exception {
        String text = "爱你一万年"; // 二维码内容
         String logoPath = "D:\work\二维码.png"; //嵌入二维码的图片路径
        String destPath = "D:\work";//生成二维码的地址
        QRCodeUtil.encode(text, logoPath, destPath, false);//生成二维码
//        String decode = QRCodeUtil.decode("D:\work/659518998202810368.jpg");//解析二维码
//        System.out.println(decode);//答应解析二维码的内容
    }
}

待补充。。。

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