java通过opencv解析二维码（微信开源解码工具）

        以往java解析二维码都是使用google.zxing，但是zxing解析二维码的成功率比较低，很多美化或者个性化的二维码无法解析。

        微信开源了其二维码的解码功能，并贡献给 OpenCV 社区。其开源的 wechat_qrcode 项目被收录到 OpenCV contrib 项目中。从 OpenCV 4.5.2 版本开始，就可以直接使用。

先导入依赖包

<dependency>
   <groupId>org.bytedecogroupId>
   <artifactId>javacppartifactId>
   <version>1.5.7version>
   <classifier>windows-x86_64classifier>
dependency>
<dependency>
    <groupId>org.bytedecogroupId>
    <artifactId>openblasartifactId>
    <version>0.3.19-1.5.7version>
    <classifier>windows-x86_64classifier>
dependency>
<dependency>
    <groupId>org.bytedecogroupId>
    <artifactId>opencvartifactId>
    <version>4.5.5-1.5.7version>
dependency>
<dependency>
     <groupId>org.bytedecogroupId>
     <artifactId>opencvartifactId>
      <version>4.5.5-1.5.7version>
      <classifier>windows-x86_64classifier>
dependency>

以上依赖用于windows系统 如果要发布到liunx系统把windows-x86_64改成liunx-x86_64

下面是解析代码

package com.dyserver.bean;
 
import org.bytedeco.opencv.opencv_core.Mat;
import org.bytedeco.opencv.opencv_core.StringVector;
import org.bytedeco.opencv.opencv_wechat_qrcode.WeChatQRCode;
 
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.net.URLConnection;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;
 
import javax.imageio.ImageIO;
 
import static org.bytedeco.opencv.global.opencv_imgcodecs.imread;
 
/**
 * 
 */
public class WeChatDeCode {
 
	public static void main(String... args) {
		Mat img = imread("d:\\img" + "\\" + "1.png");
		System.out.println(deCode(img));
		
		//下载二维码到本地识别
		String url="";
		System.out.println(openPic(url));
	}
 
	public static String openPic(String url) {
 
		String savePath = "d:\\img";
		String filename = UUID.randomUUID().toString() + ".jpg";
		String re="0";
		try {
			dxz(url, savePath, filename);		
			Mat img = imread(savePath + "\\" + filename);
			re=deCode(img);
			//如果识别失败那么尝试放大缩小图片尝试识别，提高准确率
			if(re.equals("0")) {
				ys(savePath, filename);
				Mat img1 = imread(savePath + "\\1_" + filename);
				re=deCode(img1);
			}
			if(re.equals("0")) {
				fd(savePath, filename);
				Mat img2 = imread(savePath + "\\2_" + filename);
				re=deCode(img2);
			}
			return re;
			
			
			
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			return "0";
		}
	}
 
	private static void ys(String savePath, String filename) throws Exception {
		try {
			// 读取原始图片
			BufferedImage image = ImageIO.read(new FileInputStream(savePath + "\\" + filename));
			System.out.println("Width: " + image.getWidth());
			System.out.println("Height: " + image.getHeight());
			// 调整图片大小
			BufferedImage newImage = ImageUtils.resizeImage(image, image.getWidth()*2, image.getHeight()*2);
			// 图像缓冲区图片保存为图片文件(文件不存在会自动创建文件保存，文件存在会覆盖原文件保存)
			ImageIO.write(newImage, "jpg", new File(savePath + "\\1_" + filename));
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
 
	private static void fd(String savePath, String filename) throws Exception {
		try {
			// 读取原始图片
			BufferedImage image = ImageIO.read(new FileInputStream(savePath + "\\" + filename));
			System.out.println("Width: " + image.getWidth());
			System.out.println("Height: " + image.getHeight());
			// 调整图片大小
			BufferedImage newImage = ImageUtils.resizeImage(image, 200, 200);
			// 图像缓冲区图片保存为图片文件(文件不存在会自动创建文件保存，文件存在会覆盖原文件保存)
			ImageIO.write(newImage, "jpg", new File(savePath + "\\2_" + filename));
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
 
	private static void dxz(String urlString, String savePath, String filename) throws Exception {
		// 构造URL
		URL url = new URL(urlString);
		// 打开连接
		URLConnection con = url.openConnection();
		// 设置请求超时为20s
		con.setConnectTimeout(20 * 1000);
		// 文件路径不存在 则创建
		File sf = new File(savePath);
		if (!sf.exists()) {
			sf.mkdirs();
		}
		// jdk 1.7 新特性自动关闭
		try (InputStream in = con.getInputStream();
				OutputStream out = new FileOutputStream(sf.getPath() + "\\" + filename)) {
			// 创建缓冲区
			byte[] buff = new byte[1024];
			int n;
			// 开始读取
			while ((n = in.read(buff)) >= 0) {
				out.write(buff, 0, n);
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
 
	private static String deCode(Mat img) {
		// 微信二维码对象，要返回二维码坐标前2个参数必传；后2个在二维码小或不清晰时必传。
		WeChatQRCode we = new WeChatQRCode();
		List points = new ArrayList();
		// 微信二维码引擎解码，返回的valList中存放的是解码后的数据，points中Mat存放的是二维码4个角的坐标
		StringVector stringVector = we.detectAndDecode(img);
 
		if (stringVector.empty()) {
			return "0";
		}
 
		System.out.println(stringVector.get(0).getString(StandardCharsets.UTF_8));
		return stringVector.get(0).getString(StandardCharsets.UTF_8);
	}
 
}