1、二維碼簡介

二維碼糾錯(cuò)級別

2、ZXing簡介

3、示例

3.1 搭建一個(gè)maven項(xiàng)目，引入Zxing依賴包

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

3.2 創(chuàng)建QrCodeUtil.java 類

package  QrCodeUtil;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Date;
import java.util.Hashtable;

import javax.imageio.ImageIO;


import com.alibaba.druid.util.StringUtils;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.WriterException;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;

/**
 * 生成二維碼
 */
public class QrCodeUtil {

    private static final int BLACK = 0xFF000000;
    private static final int WHITE = 0xFFFFFFFF;
    private static final int margin = 0;
    private static final int LogoPart = 4;

    public static void main(String[] args) throws WriterException {
//二維碼內(nèi)容
        String content = "IT技術(shù)分享社區(qū)，一個(gè)有態(tài)度的互聯(lián)網(wǎng)社區(qū)交流平臺(tái)";
        String logoPath = "D:\\logo.png"; // 二維碼中間的logo信息 非必須
        String format = "jpg";
        int width = 120; // 二維碼寬度
        int height = 120;// 二維碼高度
        // 設(shè)置二維碼矩陣的信息
        BitMatrix bitMatrix = setBitMatrix(content, width, height);
        // 設(shè)置輸出流
        OutputStream outStream = null;
        String path = "d:/Code" + new Date().getTime() + ".png";//設(shè)置二維碼的文件名
        try {
            outStream = new FileOutputStream(new File(path));
            // 目前 針對容錯(cuò)等級為H reduceWhiteArea  二維碼空白區(qū)域的大小 根據(jù)實(shí)際情況設(shè)置，如果二維碼內(nèi)容長度不固定的話 需要自己根據(jù)實(shí)際情況計(jì)算reduceWhiteArea的大小
            writeToFile(bitMatrix, format, outStream, logoPath, 5);
            outStream.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 設(shè)置生成二維碼矩陣信息
     * @param content 二維碼圖片內(nèi)容
     * @param width   二維碼圖片寬度
     * @param height  二維碼圖片高度
     * @throws WriterException
     */
    private static BitMatrix setBitMatrix(String content, int width, int height) throws WriterException {
        BitMatrix bitMatrix = null;
        Hashtable<EncodeHintType, Object> hints = new Hashtable<EncodeHintType, Object>();
        hints.put(EncodeHintType.CHARACTER_SET, "UTF-8"); // 指定編碼方式,避免中文亂碼
        hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H); // 指定糾錯(cuò)等級 如果二維碼里面的內(nèi)容比較多的話推薦使用H 容錯(cuò)率30%， 這樣可以避免一些掃描不出來的問題
        hints.put(EncodeHintType.MARGIN, margin); // 指定二維碼四周白色區(qū)域大小 官方的這個(gè)方法目前沒有沒有作用默認(rèn)設(shè)置為0
        bitMatrix = new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE, width, height, hints);
        return bitMatrix;
    }
    /**
     * @param matrix
     * @param format
     * @param outStream
     * @param logoPath        logo圖片
     * @param reduceWhiteArea 二維碼空白區(qū)域設(shè)置
     * @throws IOException
     */
    private static void writeToFile(BitMatrix matrix, String format, OutputStream outStream, String logoPath, int reduceWhiteArea) throws IOException {
        BufferedImage image = toBufferedImage(matrix, reduceWhiteArea);
        // 如果設(shè)置了二維碼里面的logo 加入LOGO水印
        if (!StringUtils.isEmpty(logoPath)) {
            image = addLogo(image, logoPath);
        }
        ImageIO.write(image, format, outStream);
    }

    /**
     *
     * @param matrix
     * @param reduceWhiteArea
     * @return
     */
    private static BufferedImage toBufferedImage(BitMatrix matrix, int reduceWhiteArea) {
        int width = matrix.getWidth();
        int height = matrix.getHeight();
        BufferedImage image = new BufferedImage(width - 2 * reduceWhiteArea, height - 2 * reduceWhiteArea, BufferedImage.TYPE_3BYTE_BGR);
        for (int x = reduceWhiteArea; x < width - reduceWhiteArea; x++) {
            for (int y = reduceWhiteArea; y < height - reduceWhiteArea; y++) {
                image.setRGB(x - reduceWhiteArea, y - reduceWhiteArea, matrix.get(x, y) ? BLACK : WHITE);
            }
        }
        return image;
    }

    /**
     * 給二維碼圖片中繪制logo信息 非必須
     * @param image    二維碼圖片
     * @param logoPath logo圖片路徑
     */
    private static BufferedImage addLogo(BufferedImage image, String logoPath) throws IOException {
        Graphics2D g = image.createGraphics();
        BufferedImage logoImage = ImageIO.read(new File(logoPath));
        // 計(jì)算logo圖片大小,可適應(yīng)長方形圖片,根據(jù)較短邊生成正方形
        int width = image.getWidth() < image.getHeight() ? image.getWidth() / LogoPart : image.getHeight() / LogoPart;
        int height = width;
        // 計(jì)算logo圖片放置位置
        int x = (image.getWidth() - width) / 2;
        int y = (image.getHeight() - height) / 2;
        // 在二維碼圖片上繪制中間的logo
        g.drawImage(logoImage, x, y, width, height, null);
        // 繪制logo邊框,可選
        g.setStroke(new BasicStroke(2)); // 畫筆粗細(xì)
        g.setColor(Color.WHITE); // 邊框顏色
        g.drawRect(x, y, width, height); // 矩形邊框
        logoImage.flush();
        g.dispose();
        return image;
    }

}