在Spring Boot项目中整合ZXing库来生成二维码是一个常见的需求。
zxing，全称"Zebra Crossing"，是一个功能强大的开源Java库，专门用于二维码的生成与解析。它不仅能够生成QR码，还能解析包括QR码在内的多种二维码格式。ZXing提供了多语言API，使得开发者能够轻松地将二维码功能集成到各种应用中。它支持Android、iOS、Java等多个平台，并且除了QR码，还能解析其他一维码和二维码，如EAN、UPC、DataMatrix等。
1. 添加zxing库的依赖
代码语言：javascript复制<dependency>
<groupId>com.google.zxing</groupId>
<artifactId>core</artifactId>
<version>3.5.2</version>
</dependency>
<dependency>
<groupId>com.google.zxing</groupId>
<artifactId>javase</artifactId>
<version>3.5.2</version>
</dependency>2. 生成二维码
创建一个SpringBoot服务类QRCodeService，用于生成二维码图片：
import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.client.j2se.MatrixToImageWriter;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
import org.springframework.stereotype.Service;
import java.io.IOException;
import java.nio.file.FileSystems;
import java.nio.file.Path;
import java.util.HashMap;
import java.util.Map;
@Service
public class QRCodeService {
public void generateQRCodeImage(String text, int width, int height, String filePath)
throws IOException {
Map<EncodeHintType, Object> hints = new HashMap<>();
hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.M);
hints.put(EncodeHintType.MARGIN, 2);
BitMatrix bitMatrix = new MultiFormatWriter().encode(text, BarcodeFormat.QR_CODE, width, height, hints);
Path path = FileSystems.getDefault().getPath(filePath);
MatrixToImageWriter.writeToPath(bitMatrix, "PNG", path);
}
}3. 调用二维码服务
3.1 将二维码图拍你保存
最后在SpringBoot的Controller中调用这个服务：
代码语言：javascript复制import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import java.io.IOException;
@RestController
public class QRCodeController {
@Autowired
private QRCodeService qrCodeService;
@GetMapping("/generateQRCode")
public String generateQRCode(@RequestParam String text, @RequestParam int width, @RequestParam int height) {
try {
qrCodeService.generateQRCodeImage(text, width, height, "myqrcode.png");
return "QR Code generated successfully!";
} catch (IOException e) {
return "QR Code generation failed: " e.getMessage();
}
}
}当访问/generateQRCode端点并传递text、width和height参数时，它将生成一个名为myqrcode.png的二维码图片并保存到项目根目录下。
http://localhost:8080/generateQRCode?text=Hello,World!&width=350&height=3503.2. 直接返回二维码图片
修改QRCodeController来返回二维码图片：
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.ByteArrayResource;
import org.springframework.core.io.Resource;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import javax.imageio.ImageIO;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
@RestController
public class QRCodeController {
@GetMapping("/generateQRCode")
public ResponseEntity<Resource> generateQRCode(@RequestParam String text, @RequestParam Integer width, @RequestParam Integer height) throws IOException {
BitMatrix bitMatrix = new MultiFormatWriter().encode(text, BarcodeFormat.QR_CODE, width, height, getHints());
BufferedImage qrCodeImage = MatrixToImageWriter.toBufferedImage(bitMatrix);
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
ImageIO.write(qrCodeImage, "PNG", byteArrayOutputStream);
byte[] qrCodeBytes = byteArrayOutputStream.toByteArray();
HttpHeaders headers = new HttpHeaders();
headers.add(HttpHeaders.CONTENT_TYPE, MediaType.IMAGE_PNG_VALUE);
return ResponseEntity.ok()
.headers(headers)
.contentLength(qrCodeBytes.length)
.body(new ByteArrayResource(qrCodeBytes));
}
private Map<EncodeHintType, Object> getHints() {
Map<EncodeHintType, Object> hints = new HashMap<>();
hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.M);
hints.put(EncodeHintType.MARGIN, 2);
return hints;
}
}generateQRCode先生成二维码的BitMatrix，然后转换为BufferedImage，以便获取二维码图片的字节流。
3.2 注册BufferedImage消息转换器返回图片
3.2中返回图片也可以通过注册一个SpringBoot的消息转换器来实现:
代码语言：javascript复制@Bean
public HttpMessageConverter<BufferedImage> createImageHttpMessageConverter() {
return new BufferedImageHttpMessageConverter();
}返回图片
代码语言：javascript复制package com.example.demo.controller;
import java.awt.image.BufferedImage;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.client.j2se.MatrixToImageWriter;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.QRCodeWriter;
@RestController
@RequestMapping("/qr")
public class QrCodeController {
@GetMapping(value = "/{barcode}", produces = MediaType.IMAGE_PNG_VALUE)
public ResponseEntity<BufferedImage> barbecueEAN13Barcode(@PathVariable("barcode") String barcode)
throws Exception {
QRCodeWriter barcodeWriter = new QRCodeWriter();
BitMatrix bitMatrix =
barcodeWriter.encode(barcode, BarcodeFormat.QR_CODE, 200, 200);
return new ResponseEntity<>(MatrixToImageWriter.toBufferedImage(bitMatrix),HttpStatus.OK);
}
}现在，当访问/qr端点时，将直接收到一个二维码图片作为响应。
