解决Type mismatch: cannot convert from ByteMatrix to BitMatrix

问题背景: 微信支付时，生成二维码使用的是zxing 

BitMatrix bitMatrix = new MultiFormatWriter().encode(code_url,
					BarcodeFormat.QR_CODE, width, height, hints); //Type mismatch: cannot convert from ByteMatrix to BitMatrixBitMatrix bitM