java生成二维码图片

1.依赖

    <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><version>2.7.18</version></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId><version>2.7.18</version></dependency><dependency><groupId>com.google.zxing</groupId><artifactId>javase</artifactId><version>3.5.2</version><scope>compile</scope></dependency>

2.代码

package org.example.qrcode;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.mock.web.MockMultipartFile;
import org.springframework.web.multipart.MultipartFile;import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;public class MyQrcode {public static MultipartFile generateQrCode(String content, int width, int height) {MultipartFile multipartFile = null;try {Map<EncodeHintType, Object> hints = new HashMap<>();hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);BitMatrix bitMatrix = null;bitMatrix = new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE, width, height, hints);BufferedImage bufferedImage = MatrixToImageWriter.toBufferedImage(bitMatrix);ByteArrayOutputStream baos = new ByteArrayOutputStream();ImageIO.write(bufferedImage,"png",new File("./ad.png"));ImageIO.write(bufferedImage, "png", baos);byte[] imageBytes = baos.toByteArray();ByteArrayInputStream bais = new ByteArrayInputStream(imageBytes);String fileName = "qrcode.png";multipartFile = new MockMultipartFile("file", fileName, "image/png", bais);} catch (Exception e) {e.printStackTrace();}return multipartFile;}public static void main(String[] args) throws IOException {generateQrCode("中国", 300, 300);}
}

3.说明

代码中有两次ImageIO.write的方法，第一个是把二维码图片存储到了指定的路径，适合本地测试；第二个是把文件流通过multipartFile返回了，适合生成二维码文件流后上传到服务器的操作。两个方法留一个即可。