java實現二維碼的生成與解析

簡單介紹下二維碼：二維碼其實就是一種編碼技術，只是這種編碼技術是用在圖片上了，將給定的一些文字，數字轉換為一張經過特定編碼的圖片，而解析二維碼則相反，就是將一張經過編碼的圖片解析為數字或者文字。

當然了，這種編碼的低層實現並不是那么的簡單，都是那些頂級研發人員做的事，我們只需要簡單了解並知道怎么使用就可以了。

那么肯定是要導入jar包依賴的吧，那不用說，是要導包的，我用的是谷歌提供的一個com.google.zxing.core版本是3.3.0的。

下面我們直接創建一個maven項目，用maven管理jar包很方便，而且我們需要的jar包基本都可以從官網下載進行依賴的添加。

創建好maven項目后，在項目的pom.xml中添加依賴：

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

上面這段依賴可以直接到maven的官網進行copy，在maven依賴查詢官網直接搜索zxing，我用的是3.3.0的版本。

相信大家對maven也已經比較熟悉了，具體大家可參考我的文章里面的《maven入門筆記》

jar包依賴添加完后，我們直接上代碼：

第一個類：

package com.yc.qrcode;
 
import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import com.google.zxing.LuminanceSource;
 
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;
    }
 
    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;
    }
 
    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;
    }
 
    public boolean isCropSupported() {
        return true;
    }
 
    public LuminanceSource crop(int left, int top, int width, int height) {
        return new BufferedImageLuminanceSource(image, this.left + left, this.top + top, width, height);
    }
 
    public boolean isRotateSupported() {
        return true;
    }
 
    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);
    }
 
}

上面這個類是谷歌提供的幫助類

第二個類：

package com.zh.quartz_demo.util;


import java.awt.BasicStroke;
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.IOException;
import java.io.OutputStream;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.Map;
import java.util.Random;
import javax.imageio.ImageIO;

import com.google.zxing.*;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.common.HybridBinarizer;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
import com.zh.quartz_demo.test.BufferedImageLuminanceSource;

public class QRCodeUtil {
    private static final String CHARSET = "utf-8";
    private static final String FORMAT_NAME = "JPG";
    // 二維碼尺寸
    private static final int QRCODE_SIZE = 300;
    // LOGO寬度
    private static final int WIDTH = 60;
    // LOGO高度
    private static final int HEIGHT = 60;

    private static BufferedImage createImage(String content, String imgPath, boolean needCompress) throws Exception {
        Hashtable hints = new Hashtable();
        hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
        hints.put(EncodeHintType.CHARACTER_SET, CHARSET);
        hints.put(EncodeHintType.MARGIN, 1);
        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;
        }
        // 插入圖片
        QRCodeUtil.insertImage(image, imgPath, needCompress);
        return image;
    }

    private static void insertImage(BufferedImage source, String imgPath, boolean needCompress) throws Exception {
        File file = new File(imgPath);
        if (!file.exists()) {
            System.err.println("" + imgPath + "   該文件不存在！");
            return;
        }
        Image src = ImageIO.read(new File(imgPath));
        int width = src.getWidth(null);
        int height = src.getHeight(null);
        if (needCompress) { // 壓縮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); // 繪制縮小后的圖
            g.dispose();
            src = image;
        }
        // 插入LOGO
        Graphics2D graph = source.createGraphics();
        int x = (QRCODE_SIZE - width) / 2;
        int y = (QRCODE_SIZE - height) / 2;
        graph.drawImage(src, x, y, width, height, null);
        Shape shape = new RoundRectangle2D.Float(x, y, width, width, 6, 6);
        graph.setStroke(new BasicStroke(3f));
        graph.draw(shape);
        graph.dispose();
    }

    public static void encode(String content, String imgPath, String destPath, boolean needCompress) throws Exception {
        BufferedImage image = QRCodeUtil.createImage(content, imgPath, needCompress);
        mkdirs(destPath);
        ImageIO.write(image, FORMAT_NAME, new File(destPath));
    }

    public static BufferedImage encode(String content, String imgPath, boolean needCompress) throws Exception {
        BufferedImage image = QRCodeUtil.createImage(content, imgPath, needCompress);
        return image;
    }

    public static void mkdirs(String destPath) {
        File file = new File(destPath);
        // 當文件夾不存在時，mkdirs會自動創建多層目錄，區別於mkdir．(mkdir如果父目錄不存在則會拋出異常)
        if (!file.exists() && !file.isDirectory()) {
            file.mkdirs();
        }
    }

    public static void encode(String content, String imgPath, String destPath) throws Exception {
        QRCodeUtil.encode(content, imgPath, destPath, false);
    }
    // 被注釋的方法
    /*
     * public static void encode(String content, String destPath, boolean
     * needCompress) throws Exception { QRCodeUtil.encode(content, null, destPath,
     * needCompress); }
     */

    public static void encode(String content, String destPath) throws Exception {
        QRCodeUtil.encode(content, null, destPath, false);
    }

    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);
    }

    public static void encode(String content, OutputStream output) throws Exception {
        QRCodeUtil.encode(content, null, output, false);
    }

    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 hints = new Hashtable();
        hints.put(DecodeHintType.CHARACTER_SET, CHARSET);
        result = new MultiFormatReader().decode(bitmap, hints);
        String resultStr = result.getText();
        return resultStr;
    }

    public static String decode(String path) throws Exception {
        return QRCodeUtil.decode(new File(path));
    }

 /*
     *  生成二維碼
     * @param content 二維碼的內容
     * @return BitMatrix對象
     */
    public static BitMatrix createCode(String content) throws IOException {
        //二維碼的寬高
        int width = 200;
        int height = 200;

        //其他參數，如字符集編碼
        Map<EncodeHintType, Object> hints = new HashMap<EncodeHintType, Object>();
        hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
        //容錯級別為H
        hints.put(EncodeHintType.ERROR_CORRECTION , ErrorCorrectionLevel.H);
        //白邊的寬度，可取0~4
        hints.put(EncodeHintType.MARGIN , 0);

        BitMatrix bitMatrix = null;
        try {
            //生成矩陣，因為我的業務場景傳來的是編碼之后的URL，所以先解碼
            bitMatrix = new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE, width, height, hints);

            //bitMatrix = deleteWhite(bitMatrix);
        } catch (WriterException e) {
            e.printStackTrace();
        }

        return bitMatrix;
    }

}

 

上面這個是工具類，里面的方法我都寫了注釋，編碼和解碼方法都有多個重載方法，根據參數列表的不同，選擇不同的方法執行。其中生成的二維碼的圖片的名字可以隨機命名，也可以自己給定。我把隨機命名的方法注釋了，用的是給定圖片名稱。

主類：

 public static void main(String[] args) {
        try {
            // 存放在二維碼中的內容
            String text = "我是小銘";
            // 嵌入二維碼的圖片路徑
            String imgPath = "C:\\Users\\zipzia02\\Desktop\\微信圖片_20191204154102.jpg";//"D:/img/59fc0ffb3ecf2.jpg";
            // 生成的二維碼的路徑及名稱
            String destPath = "D:/img/jam.jpg";
            //生成二維碼
            QRCodeUtil.encode(text, imgPath, destPath, true);

            // 解析二維碼
            String str = QRCodeUtil.decode(destPath);
            // 打印出解析出的內容
            System.out.println(str);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

 

請求api：

@GetMapping("getCode")
public void getCode(HttpServletResponse response) {

    try {
        // 設置響應流信息
        response.setContentType("image/jpg");
        response.setHeader("Pragma", "no-cache");
        response.setHeader("Cache-Control", "no-cache");
        response.setDateHeader("Expires", 0);

        OutputStream stream = response.getOutputStream();

        //獲取一個二維碼圖片
        BitMatrix bitMatrix = new QRCodeService().GetQRCode();//調用層

        //以流的形式輸出到前端
        MatrixToImageWriter.writeToStream(bitMatrix, "jpg", stream);


    } catch (Exception e) {
        e.printStackTrace();
    }

}

QRCodeService類：

public class QRCodeService {

public BitMatrix GetQRCode() {
        BitMatrix bitMatrix = null;
        try{

            String content = "包含的信息";

            //調用接口生成二維碼
            QRCodeUtils.createCode(content);
            //獲取一個二維碼圖片
            bitMatrix = QRCodeUtils.createCode(content);


        } catch (IOException e) {
            log.error("獲取二維碼異常", e);
        }
        return bitMatrix;
    }
}

 

 

這里面的代碼注釋我都寫得很清楚了，相信大家都可以看明白，其中：

生成二維碼方法：

QRCodeUtil.encode(text, imgPath, destPath, true);

text：編碼到二維碼中的內容，這里是“我是小銘”

imgPath：要嵌入二維碼的圖片路徑，如果不寫或者為null則生成一個沒有嵌入圖片的純凈的二維碼

destPath：生成的二維碼的存放路徑

true：表示將嵌入二維碼的圖片進行壓縮，如果為“false”則表示不壓縮。

解析二維碼方法：

QRCodeUtil.decode(destPath);

destPath：將要解析的二維碼的存放路徑

該方法返回值為String類型，即返回解析出的文字或者數字等。  

轉載：https://blog.csdn.net/jam_fanatic/article/details/82818857