package dev.simplesolution.generateqr.controller;

​

import dev.simplesolution.generateqr.service.QRCodeService;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Controller;

import org.springframework.ui.Model;

import org.springframework.web.bind.annotation.GetMapping;

import org.springframework.web.bind.annotation.PostMapping;

import org.springframework.web.bind.annotation.RequestMapping;

​

import javax.servlet.http.HttpServletResponse;

import java.io.IOException;

import java.io.OutputStream;

​

@Controller

public class QRCodeController {

​

    @Autowired

    private QRCodeService qrCodeService;

​

    @RequestMapping("/")

    public String index() {

        return "index";

    }

​

    @PostMapping("/showQRCode")

    public String showQRCode(String qrContent, Model model) {

        model.addAttribute("qrCodeContent", "/generateQRCode?qrContent=" + qrContent);

        return "show-qr-code";

    }

​

    @GetMapping("/generateQRCode")

    public void generateQRCode(String qrContent, HttpServletResponse response) throws IOException {

        response.setContentType("image/png");

        byte[] qrCode = qrCodeService.generateQRCode(qrContent, 500, 500);

        OutputStream outputStream = response.getOutputStream();

        outputStream.write(qrCode);

    }

}

package dev.simplesolution.generateqr.service.impl;

​

import com.google.zxing.BarcodeFormat;

import com.google.zxing.WriterException;

import com.google.zxing.client.j2se.MatrixToImageWriter;

import com.google.zxing.common.BitMatrix;

import com.google.zxing.qrcode.QRCodeWriter;

import dev.simplesolution.generateqr.service.QRCodeService;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import org.springframework.stereotype.Service;

​

import java.io.ByteArrayOutputStream;

import java.io.IOException;

​

@Service

public class QRCodeServiceImpl implements QRCodeService {

​

    private Logger logger = LoggerFactory.getLogger(QRCodeServiceImpl.class);

​

    @Override

    public byte[] generateQRCode(String qrContent, int width, int height) {

        try {

            QRCodeWriter qrCodeWriter = new QRCodeWriter();

            BitMatrix bitMatrix = qrCodeWriter.encode(qrContent, BarcodeFormat.QR_CODE, width, height);

            ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();

            MatrixToImageWriter.writeToStream(bitMatrix, "PNG", byteArrayOutputStream);

            return byteArrayOutputStream.toByteArray();

        } catch (WriterException e) {

            logger.error(e.getMessage(), e);

        } catch (IOException e) {

            logger.error(e.getMessage(), e);

        }

        return null;

    }

}