后台Java生成二维码
这里用到了谷歌的zxing包，maven依赖如下：
<!-- 二维码依赖开始--><dependency><groupId>com.google.zxing</groupId><artifactId>core</artifactId><version>3.4.0</version></dependency><!-- 二维码依赖结束-->
一、场景
需要根据设备信息生成二维码，然后写回给前端去下载。
二、工具类代码
import com.google.zxing.BarcodeFormat;import com.google.zxing.EncodeHintType;import com.google.zxing.MultiFormatWriter;import com.google.zxing.WriterException;import com.mon.BitMatrix;import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;import lombok.extern.slf4j.Slf4j;import mons.lang3.StringUtils;import org.ponent;import java.awt.*;import java.awt.image.BufferedImage;import java.util.Hashtable;/*** 生成二维码工具类.** @author linzp* @version 1.0.0* CreateDate /1/26 10:39*/@Slf4j@Componentpublic class QrCodeUtils {//二维码宽度private static final int QRCODE_SIZE = 430;//编码private static final String CHARSET = "utf-8";// 二维码绘制高度偏移量，留出空间写文字描述二维码信息private static final int OFFSET_HEIGHT = 25;//二维码标题字体private static final String TITLE_FONT = "黑体";//标题前缀private static final String TITLE_PREFIX = "编号：";/*** 生成二维码.** @param content 内容* @return 图片*/public BufferedImage buildQrCodeImage(String content) {return createImage(content, content);}/*** 生成二维码.** @param content 扫描成功的内容* @param title 二维码标题* @return 二维码图片*/private BufferedImage createImage(String content, String title) {//等同于hashmap,hashtable是线程安全的Hashtable hints = new Hashtable();hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);hints.put(EncodeHintType.CHARACTER_SET, CHARSET);hints.put(EncodeHintType.MARGIN, 1);BitMatrix bitMatrix = null;try {bitMatrix = new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE, QRCODE_SIZE, QRCODE_SIZE, hints);} catch (WriterException e) {log.error("生成二维码异常了..content【{}】", content, e);throw new RuntimeException("生成二维码信息异常，请稍后重试");}int width = bitMatrix.getWidth();int height = bitMatrix.getHeight();BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);for (int x = 0; x < width; x++) {for (int y = 0; y < height; y++) {image.setRGB(x, y, bitMatrix.get(x, y) ? 0xFF000000 : 0xFFFFFFFF);}}log.info("生成二维码成功！");//有标题，合成带标题的二维码if (StringUtils.isNotBlank(title)) {return drawDetailForQR(image, title);}//直接返回生成的二维码return image;}/*** 绘制二维码描述信息.** @param source 源二维码图片* @param title 二维码标题* @return 合成后的图片*/private BufferedImage drawDetailForQR(BufferedImage source, String title) {//新建模板图片BufferedImage bufferedImage = new BufferedImage(QRCODE_SIZE, QRCODE_SIZE + OFFSET_HEIGHT, BufferedImage.TYPE_INT_RGB);Graphics2D graphics = bufferedImage.createGraphics();//绘制矩形背景graphics.setColor(Color.white);graphics.fillRect(0, 0, QRCODE_SIZE, OFFSET_HEIGHT);//绘制描述信息Font font = new Font(TITLE_FONT, Font.PLAIN, 22);graphics.setColor(Color.black);graphics.setFont(font);graphics.drawString(TITLE_PREFIX + title, 20, OFFSET_HEIGHT - 2);//绘制二维码graphics.drawImage(source, 0, OFFSET_HEIGHT, QRCODE_SIZE, QRCODE_SIZE, null);graphics.dispose();return bufferedImage;}}
正常生成二维码就好了，但是我需要再拼接二维码的说明信息，好下载时分辨出是那个设备的二维码。于是做了点加工。
三、效果图
码字不易，如果帮助到了你，顺便点个赞叭~
