JAVA获取小程序二维码A,B,C接口，然后解析遇到的坑

一、问题描述

最近公司有个需求是，从小程序哪里获取二维码，然后从二维码中解析出URL来，自己定制下二维码。。。嫌微信生成的码太难看了。。。微信小程序的获取二维码的文档如下:https://developers.weixin.qq.com/miniprogram/dev/api/qrcode.html 看着这个文档。。。就想吐槽下。。写的太含糊了。

竟然没写返回值是什么。。最后得知，它是以流的形式返回。。。文档里有三A、B、C三种类型的接口，不清楚微信怎么想的。。。分这么多种接口，做什么。。A,B接口有生成次数限制,B接口没有限制。。

测试代码如下:

public class Test {
    public static void main(String[] args) {
        try {
            URL url = new URL("https://api.weixin.qq.com/wxa/getwxacodeunlimit?access_token=你的access_token");
            HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
            httpURLConnection.setRequestMethod("POST");// 提交模式
            // conn.setConnectTimeout(10000);//连接超时 单位毫秒
            // conn.setReadTimeout(2000);//读取超时 单位毫秒
            // 发送POST请求必须设置如下两行
            httpURLConnection.setDoOutput(true);
            httpURLConnection.setDoInput(true);
            // 获取URLConnection对象对应的输出流
            PrintWriter printWriter = new PrintWriter(httpURLConnection.getOutputStream());
            // 发送请求参数
            JSONObject paramJson = new JSONObject();
            paramJson.put("scene", "a=1234567890");
            paramJson.put("page", "pages/index/index");
            paramJson.put("width", 430);
            paramJson.put("auto_color", true);
            /**
             * line_color生效
             * paramJson.put("auto_color", false);
             * JSONObject lineColor = new JSONObject();
             * lineColor.put("r", 0);
             * lineColor.put("g", 0);
             * lineColor.put("b", 0);
             * paramJson.put("line_color", lineColor);
             * */

            printWriter.write(paramJson.toString());
            // flush输出流的缓冲
            printWriter.flush();
            //开始获取数据
            BufferedInputStream bis = new BufferedInputStream(httpURLConnection.getInputStream());
            OutputStream os = new FileOutputStream(new File("/Users/Xxxx/Music/abc.png"));
            int len;
            byte[] arr = new byte[1024];
            while ((len = bis.read(arr)) != -1) {
                os.write(arr, 0, len);
                os.flush();
            }
            os.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

生成的二维码如下:

但是这种二维码不管怎么搞，都解析不出来二维码中的数据，我试了QRCode.jar与Zxing都不能解析出来，都是报:

com.google.zxing.NotFoundException

这种错，网上说是二维码复杂了,或者是中间有LOGO的时候就报错。。但是C接口返回的二维码

通过Zxing解析是也报上面那种错，但是在网上找到了中解决方法，把二维码下面的那串中文去掉就可以了。

二、解决方法

解决方法如下，在微信返回的流中，对图片解析截取:

            ByteArrayInputStream inputStream= new ByteArrayInputStream(swapStream.toByteArray());
            BufferedImage image = ImageIO.read(inputStream);
            /**裁剪原图  目前访问微信 微信返回的是 470*535 像素 170620*/
            BufferedImage subImage = image.getSubimage(0, 0, image.getWidth(), (int) (image.getHeight() * 0.85));

把下面的中文去掉,效果如下

相对应的URL为:

https://mp.weixin.qq.com/a/~~JtIAAAEESEGtXoPLOk~fPZXTPs0T7Y3SaxauUqasw~~

完整代码如下:

1.引入Zxing

		<dependency>
			<groupId>com.google.zxing</groupId>
			<artifactId>javase</artifactId>
			<version>3.2.1</version>
		</dependency>

2.创建BufferedImageLuminanceSource类

package com.quna.app.pay;

import com.google.zxing.LuminanceSource;

import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;

/**
 * @version: V1.0
 * @author: fendo
 * @className: BufferedImageLuminanceSource
 * @packageName: com.xxx
 * @description:
 * @data: 2018-04-17 14:23
 **/
public final 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;
    }

    @Override
    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;
    }

    @Override
    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;
    }

    @Override
    public boolean isCropSupported() {
        return true;
    }

    @Override
    public LuminanceSource crop(int left, int top, int width, int height) {
        return new BufferedImageLuminanceSource(image, this.left + left, this.top + top, width, height);
    }

    @Override
    public boolean isRotateSupported() {
        return true;
    }

    @Override
    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);
    }

}

3.二维码工具类

package com.quna.app.pay;

import com.google.zxing.*;
import com.google.zxing.common.HybridBinarizer;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;

/**
 * @version: V1.0
 * @author: fendo
 * @className: QrCodeUtils
 * @packageName: com.xxx
 * @description: 二维码工具类
 * @data: 2018-04-17 14:23
 **/
public class QrCodeUtils {

    /**
     * 解析二维码（QRCode）
     * @param image
     * @return
     */
    public static String decodeQrcode(BufferedImage image) throws NotFoundException {

        MultiFormatReader formatReader = new MultiFormatReader();

        BinaryBitmap binaryBitmap=new BinaryBitmap(new HybridBinarizer(new BufferedImageLuminanceSource(image)));

        //定义二维码的参数:
        Map<DecodeHintType, Object> hints = new HashMap<DecodeHintType, Object>();
        hints.put(DecodeHintType.CHARACTER_SET,"utf-8");//定义字符集
        hints.put(DecodeHintType.PURE_BARCODE, Boolean.TRUE);
        Result result = formatReader.decode(binaryBitmap, hints);//开始解析

        return result.getText();
    }

    /**
     * 流图片解码
     * @param   input
     * @return  String
     */
    public static String decodeQrcode(InputStream input) throws NotFoundException, IOException {

        BufferedImage image = ImageIO.read(input);
        LuminanceSource source = new BufferedImageLuminanceSource(image);
        BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));

        Map<DecodeHintType,Object> hints = new LinkedHashMap<DecodeHintType,Object>();
        // 解码设置编码方式为：utf-8，
        hints.put(DecodeHintType.CHARACTER_SET, "UTF-8");
        //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 result = new MultiFormatReader().decode(bitmap, hints);
        return result.getText();
    }


}

4.测试类

package com.quna.app.pay;

import com.alibaba.fastjson.JSONObject;
import org.junit.Test;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;

/**
 * @version: V1.0
 * @author: fendo
 * @className: TestQR
 * @packageName: com.xxx
 * @description: 二维码测试类
 * @data: 2018-04-17 14:23
 **/
public class TestQR {

    public static void main(String[] args) {
        try {
            URL url = new URL("https://api.weixin.qq.com/cgi-bin/wxaapp/createwxaqrcode?access_token=你的token");
            HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
            httpURLConnection.setRequestMethod("POST");// 提交模式
            // conn.setConnectTimeout(10000);//连接超时 单位毫秒
            // conn.setReadTimeout(2000);//读取超时 单位毫秒
            // 发送POST请求必须设置如下两行
            httpURLConnection.setDoOutput(true);
            httpURLConnection.setDoInput(true);
            // 获取URLConnection对象对应的输出流
            PrintWriter printWriter = new PrintWriter(httpURLConnection.getOutputStream());
            // 发送请求参数
            JSONObject paramJson = new JSONObject();
            paramJson.put("path", "pages/home/index");
            paramJson.put("width", 430);
            printWriter.write(paramJson.toString());
            // flush输出流的缓冲
            printWriter.flush();
            //开始获取数据
            BufferedInputStream bis = new BufferedInputStream(httpURLConnection.getInputStream());

            ByteArrayOutputStream swapStream = new ByteArrayOutputStream();
            //buff用于存放循环读取的临时数据
            byte[] buff = new byte[100];
            int rc = 0;
            while ((rc = bis.read(buff, 0, 100)) > 0) {
                swapStream.write(buff, 0, rc);
            }
            ByteArrayInputStream inputStream= new ByteArrayInputStream(swapStream.toByteArray());
            BufferedImage image = ImageIO.read(inputStream);
            /**裁剪原图  目前访问微信 微信返回的是 470*535 像素 170620*/
            BufferedImage subImage = image.getSubimage(0, 0, image.getWidth(), (int) (image.getHeight() * 0.85));

            System.out.println(QrCodeUtils.decodeQrcode(subImage));

            BufferedImage inputbig = new BufferedImage(256, 256, BufferedImage.TYPE_INT_BGR);
            Graphics2D g = (Graphics2D) inputbig.getGraphics();
            g.drawImage(subImage, 0, 0,256,256,null); //画图
            g.dispose();
            inputbig.flush();
            ImageIO.write(inputbig, "jpg", new File("C:\\Users\\luojialin\\Desktop\\jar\\2018-4-20\\124567890.png"));
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

}