将一串编码转成二维码给前端
关于后台转换base64给前端
import com.google.zxing.common.BitMatrix; import com.google.zxing.qrcode.QRCodeWriter; import java.io.ByteArrayOutputStream; import com.google.zxing.client.j2se.MatrixToImageWriter; import java.util.Base64; QRCodeWriter qrCodeWriter = new QRCodeWriter(); BitMatrix bitMatrix = qrCodeWriter.encode(userCoupon.getCoupon_no(), BarcodeFormat.QR_CODE, 375, 375); ByteArrayOutputStream pngOutputStream = new ByteArrayOutputStream(); MatrixToImageWriter.writeToStream(bitMatrix, "PNG", pngOutputStream); byte[] pngData = pngOutputStream.toByteArray(); Base64.Encoder encoder = Base64.getEncoder(); String base64Img = encoder.encodeToString(pngData); base64Img = base64Img.replaceAll("\n", "").replaceAll("\r", ""); return "data:image/jpg;base64,"+base64Img;