生成二维码

依赖

<dependency>
    <groupId>com.google.zxing</groupId>
    <artifactId>core</artifactId>
    <version>3.4.1</version>
</dependency>
<dependency>
    <groupId>com.google.zxing</groupId>
    <artifactId>javase</artifactId>
    <version>3.4.1</version>
</dependency>

service

import com.google.zxing.*;
import com.google.zxing.client.j2se.MatrixToImageWriter;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.QRCodeWriter;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
import org.springframework.stereotype.Service;

import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.HashMap;

@Service
public class QRCodeService {

    public BufferedImage generateQRCode(String text, int width, int height) throws WriterException, IOException {
        QRCodeWriter qrCodeWriter = new QRCodeWriter();

        // 设置二维码参数
        HashMap<EncodeHintType, Object> hints = new HashMap<>();
        hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);
        hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
        hints.put(EncodeHintType.MARGIN, 1);

        BitMatrix bitMatrix = qrCodeWriter.encode(text, BarcodeFormat.QR_CODE, width, height, hints);
        return MatrixToImageWriter.toBufferedImage(bitMatrix);
    }
}

controller

package boot.controller;

import boot.service.QRCodeService;
import com.google.zxing.WriterException;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.*;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;

@RestController
public class QRCodeController {

    @Autowired
    private QRCodeService qrCodeService;

    @GetMapping(value = "/qrcode/{text}", produces = MediaType.IMAGE_PNG_VALUE)
    public byte[] getQRCode(@PathVariable("text") String text,
                            @RequestParam(defaultValue = "200") int width,
                            @RequestParam(defaultValue = "200") int height) throws IOException, WriterException {
        BufferedImage qrcodeImage = qrCodeService.generateQRCode(text, width, height);

        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        ImageIO.write(qrcodeImage, "PNG", outputStream);
        return outputStream.toByteArray();
    }

    @PostMapping(value = "/qrcode2", produces = MediaType.IMAGE_PNG_VALUE)
    public byte[] getQRCode2(@RequestBody String text,
                             @RequestParam(defaultValue = "200") int width,
                             @RequestParam(defaultValue = "200") int height) throws IOException, WriterException {
        BufferedImage qrcodeImage = qrCodeService.generateQRCode(text, width, height);

        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        ImageIO.write(qrcodeImage, "PNG", outputStream);
        return outputStream.toByteArray();
    }
}

测试