如何使用 Java 生成二维码？

1. 下载jar包(QRCode.jar)

下载 址如下：

QRCode生成二维码 址：
http://swetake.com/qrcode/index-e.html

2. maven项目手动引入jar包

手动引入成功如下：BUILD SUCCESS

3. 编写实体类实现二维码的生成

package com.st.project.common;import com.swetake.util.Qrcode;import jp.sourceforge.qrcode.QRCodeDecoder;import jp.sourceforge.qrcode.data.QRCodeImage;import jp.sourceforge.qrcode.exception.DecodingFailedException;import java.awt.Color;import java.awt.Graphics2D;import java.awt.image.BufferedImage;import java.io.File;import java.io.IOException;import javax.imageio.ImageIO;/** * 二维码工具类 */public class CreateQRCode { /** * 创建二维码 * @param qrData 生成二维码中要存储的信息 * @param path 二维码图片存储路径 eg："D:/qrcode.png" * @throws Exception */ public static boolean creatQrcode(String qrData, String path) { try { Qrcode qrcode = new Qrcode(); qrcode.setQrcodeErrorCorrect('M');//纠错等级（分为L、M、H三个等级） qrcode.setQrcodeEncodeMode('B');//N代表数字，A代表a-Z，B代表其它字符 qrcode.setQrcodeVersion(7);//版本 //设置一下二维码的像素 int width = 67 + 12 * (7 - 1); int height = 67 + 12 * (7 - 1); BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); //绘图 Graphics2D gs = bufferedImage.createGraphics(); gs.setBackground(Color.WHITE); gs.setColor(Color.BLACK); gs.clearRect(0, 0, width, height);//清除下画板内容 //设置下偏移量,如果不加偏移量，有时会导致出错。 int pixoff = 2; byte[] d = qrData.getBytes("utf-8"); if (d.length > 0 && d.length < 120) { boolean[][] s = qrcode.calQrcode(d); for (int i = 0; i < s.length; i++) { for (int j = 0; j < s.length; j++) { if (s[j][i]) { gs.fillRect(j * 3 + pixoff, i * 3 + pixoff, 3, 3); } } } } gs.dispose(); bufferedImage.flush(); ImageIO.write(bufferedImage, "png", new File(path)); return true; } catch (IOException e) { e.printStackTrace(); return false; } } /** * 解析二维码（QRCode） * * @param imgPath 图片路径 * @return */ public static String decoderQRCode(String imgPath) { //QRCode 二维码图片的文件 File imageFile = new File(imgPath); BufferedImage bufImg = null; String content = null; try { bufImg = ImageIO.read(imageFile); QRCodeDecoder decoder = new QRCodeDecoder(); content = new String(decoder.decode(new TwoDimensionCodeImage(bufImg)), "utf-8"); } catch (IOException e) { System.out.println("Error: " + e.getMessage()); e.printStackTrace(); } catch (DecodingFailedException dfe) { System.out.println("Error: " + dfe.getMessage()); dfe.printStackTrace(); } return content; }}/** * 二维码基础类 */class TwoDimensionCodeImage implements QRCodeImage { //BufferedImage作用将一幅图片加载到内存中 BufferedImage bufImg; public TwoDimensionCodeImage(BufferedImage bufImg) { this.bufImg = bufImg; } @Override public int getWidth() { return bufImg.getWidth();//返回像素宽度 } @Override public int getHeight() { return bufImg.getHeight();//返回像素高度 } @Override public int getPixel(int i, int i1) { return bufImg.getRGB(i, i1);//得到长宽值，即像素值，i,i1代表像素值 }}

4. controller调用

package com.st.project.controller;import com.st.project.common.AjaxResult;import org.springframework.beans.factory.annotation.Value;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.PostMapping;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.ResponseBody;import javax.servlet.http.HttpServletRequest;import static com.st.project.common.CreateQRCode.creatQrcode;import static com.st.project.common.CreateQRCode.decoderQRCode;/** * 创建二维码 */@Controller@RequestMapping("/qrcode")public class QrcodeController { @Value("${portals.upload.image.path}") private String qrcodePath; //二维码存储路径 /** * 创建二维码 * @return */ @ResponseBody @PostMapping("/add.dd") public AjaxResult addQrcode(HttpServletRequest request){ AjaxResult ajaxResult = new AjaxResult(); ajaxResult.setState(false); String qrData=request.getParameter("qrData"); String qrSuffix=request.getParameter("qrSuffix"); String qrcode=System.currentTimeMillis()+"."+qrSuffix; String path=qrcodePath+qrcode; boolean getQrcode=creatQrcode(qrData,path); if(getQrcode==true){ ajaxResult.setState(true); ajaxResult.setData(qrcode); } return ajaxResult; } /** * 解析二维码 * @return */ @ResponseBody @PostMapping("/decoder.dd") public AjaxResult decoderQrcode(HttpServletRequest request){ AjaxResult ajaxResult = new AjaxResult(); ajaxResult.setState(false); String qrcode=request.getParameter("qrcode"); String qrData=decoderQRCode(qrcodePath+qrcode); if(qrData!=null && !"".equals(qrData)){ ajaxResult.setState(true); ajaxResult.setData(qrData); } return ajaxResult; }}

此时已生成一张名为qrcode.png的二维码图片