Java微信扫码支付流程重要点

  1 import java.awt.image.BufferedImage;   
  2 import java.io.File;
  3 import java.io.IOException;
  4 import java.util.HashMap;
  5 import java.util.Map;
  6 
  7 import javax.imageio.ImageIO;
  8 import javax.servlet.http.HttpServletResponse;
  9 
 10 import org.apache.commons.lang3.StringUtils;
 11 
 12 import com.google.zxing.BarcodeFormat;
 13 import com.google.zxing.EncodeHintType;
 14 import com.google.zxing.MultiFormatWriter;
 15 import com.google.zxing.WriterException;
 16 import com.google.zxing.common.BitMatrix;
 17 /**
 18  * 生成二维码
 19  *2015年7月7日
 20  * @author clc
 21  *
 22  */
 23 public class GenerateQrCodeUtil {
 24     private static final int WHITE = 0xFFFFFFFF;
 25     private static final int BLACK = 0xFF000000;
 26     private static final String UPLOAD ="upload";
 27     /**
 28      * 静态生成二维码 存储在磁盘上
 29      * @param content  //二维码信息
 30      * @param contextPath //上下文相对路径
 31      * @param realPath    //磁盘真实路径
 32      * @param subPath     //子路径
 33      * @return
 34      */
 35     @SuppressWarnings({ "rawtypes", "unchecked" })
 36     public static String generateQrcode(String content,String contextPath,String realPath,String subPath){
 37         if(content==null || realPath==null)
 38             return null;
 39         String fileName = generateFileName(content.getBytes())+".png";
 40         String url = "/" + UPLOAD + contextPath + "/" + subPath + "/" + fileName;//图片在项目中存储的相对路径
 41         String filePath = url;
 42         //如果是部署在服务器上的情况，则需要到webapps/下面的upload目录
 43         if (StringUtils.isNotBlank(contextPath) || realPath.endsWith("root")) {    
 44             filePath = ".." + url;
 45         }
 46         MultiFormatWriter multiFormatWriter = new MultiFormatWriter();
 47         Map hints = new HashMap();
 48         hints.put(EncodeHintType.CHARACTER_SET, "UTF-8"); //设置字符集编码类型
 49         BitMatrix bitMatrix = null;
 50         try {
 51             bitMatrix = multiFormatWriter.encode(content, BarcodeFormat.QR_CODE, 300, 300,hints);
 52             File file1 = new File(realPath,filePath); //创建存储图片的文件
 53             try {
 54                 GenerateQrCodeUtil.writeToFile(bitMatrix, "png", file1); //存储二维码图片
 55                 return filePath;
 56             } catch (IOException e) {
 57                 // TODO Auto-generated catch block
 58                 e.printStackTrace();
 59             }
 60         } catch (WriterException e1) {
 61             // TODO Auto-generated catch block
 62             e1.printStackTrace();
 63         }         
 64         return null;
 65     }
 66     private static void writeToFile(BitMatrix matrix, String format, File file) throws IOException {
 67         BufferedImage image = toBufferedImage(matrix);
 68         if (!ImageIO.write(image, format, file)) {
 69             throw new IOException("Could not write an image of format " + format + " to " + file);
 70         }
 71     }
 72     private static BufferedImage toBufferedImage(BitMatrix matrix) {
 73          int width = matrix.getWidth();
 74          int height = matrix.getHeight();
 75          BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
 76          for (int x = 0; x ) {
 77            for (int y = 0; y ) {
 78              image.setRGB(x, y, matrix.get(x, y) ? BLACK : WHITE);
 79            }
 80          }
 81          return image;
 82     }    
 83     private static String generateFileName(byte[] content) {
 84         return CryptUtil.md5(content);  //md5加密
 85     }
 86     
 87     /**
 88      * 生成二维码图片 不存储 直接以流的形式输出到页面
 89      * @param content
 90      * @param response
 91      */
 92     @SuppressWarnings({ "unchecked", "rawtypes" })
 93     public static void encodeQrcode(String content,HttpServletResponse response){
 94         if(StringUtils.isBlank(content))
 95             return;
 96         MultiFormatWriter multiFormatWriter = new MultiFormatWriter();
 97         Map hints = new HashMap();
 98         hints.put(EncodeHintType.CHARACTER_SET, "UTF-8"); //设置字符集编码类型
 99         BitMatrix bitMatrix = null;
100         try {
101             bitMatrix = multiFormatWriter.encode(content, BarcodeFormat.QR_CODE, 300, 300,hints);
102             BufferedImage image = toBufferedImage(bitMatrix);
103             //输出二维码图片流
104             try {
105                 ImageIO.write(image, "png", response.getOutputStream());
106             } catch (IOException e) {
107                 // TODO Auto-generated catch block
108                 e.printStackTrace();
109             }
110         } catch (WriterException e1) {
111             // TODO Auto-generated catch block
112             e1.printStackTrace();
113         }         
114     }
115 }

 

然后生成的图片，通过微信扫码就可以发起支付了。

支付成功后，微信会调用，你之前设置的回调函数地址。并且会把你之前传给微信的商户自定义参数带给你，以帮助商户完成余下业务流程。