526互联

使用 Java 生成二维码图片

发布时间 2023-08-27 10:17:51作者: SRIGT

0x01 准备

（1）软件版本

  • IntelliJ IDEA 2023.1.3
  • JDK 18
  • Tomcat 10.1.11
  • Maven 3.8.6

（2）技术栈

  • servlet
  • zxing
    • 谷歌项目
    • 生成黑白二维码并可以附上 logo
  • qrcode
    • github 开源项目
    • 基于并拓展 zxing

（3）创建项目

  1. 创建空项目

  2. 在 菜单栏-文件-项目结构 中设置 JDK 及语言级别

  3. 在 菜单栏-文件-设置-构建-构建工具-Maven 中配置 Maven 路径与用户设置文件 \apache-maven-3.8.6\conf\settings.xml

  4. 在项目中创建新模块

  5. 在新模块中通过“添加框架支持”添加 Web Application 4.0

    • 取消“创建 web.xml ”的选中
    • 在项目结构中选择 模块-[模块名称]-Web-Web 资源目录，修改资源目录为项目中 web 的路径，如 [project_name]\[module_name]\web

  6. 修改 pom.xml

    <!-- 打包方式 -->
 <packaging>war</packaging>

 <!-- 添加依赖 -->
 <dependencies>
     <!-- https://mvnrepository.com/artifact/jakarta.servlet/jakarta.servlet-api -->
     <dependency>
         <groupId>jakarta.servlet</groupId>
         <artifactId>jakarta.servlet-api</artifactId>
         <version>6.0.0</version>
         <scope>provided</scope>
     </dependency>
     <!-- zxing 依赖 -->
     <dependency>
         <groupId>com.google.zxing</groupId>
         <artifactId>javase</artifactId>
         <version>3.1.0</version>
     </dependency>
     <!-- zxing 需要 commons-lang 依赖 -->
     <dependency>
         <groupId>commons-lang</groupId>
         <artifactId>commons-lang</artifactId>
         <version>2.6</version>
     </dependency>
 </dependencies>

  7. 在 菜单栏-运行-编辑配置 中配置 Tomcat 服务器

    • 添加新配置，选择 Tomcat 本地服务器

    • 在 部署栏 中选择添加工件，选择 [module_name]:war exploded

    • 修改 应用上下文 为 /[module_name]

    • 修改 Tomcat 目录下 /conf/logging.properties 文件的内容以避免调试日志乱码

      java.util.logging.ConsoleHandler.encoding = GBK

0x02 zxing

（1）创建基础二维码图片

  1. 在 web/index.jsp 中编辑前端页面

    <%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
  <head>
    <title>QRCode</title>
  </head>
  <body>
  <p>输入文本：<input type="text" id="url" /><button onclick="generateQRCode()">生成二维码</button></p>
  <img id="qrcodeImg" />
  <script type="text/javascript">
    function generateQRCode() {
      document.getElementById("qrcodeImg").src = "/myqrcode/generate?url=" + document.getElementById("url").value
    }
  </script>
  </body>
</html>

  2. 新建 src/main/java/com.qrcode.servlets 包并新建 GenerateQRCode.java

    package com.qrcode.servlets;

public class GenerateQRCode extends HttpServlet {
}

  3. 在类中继承 HttpServlet 类并重写 doGet() 方法

    @WebServlet("/generate")
public class GenerateQRCode extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        // super.doGet(req, resp);
    }
}

  4. 在方法中创建 Map 集合来储存二维码相关属性

    Map map = new HashMap();
// 设置二维码的误差校正级别
map.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
// 设置二维码的字符集
map.put(EncodeHintType.CHARACTER_SET, "utf-8");
// 设置二维码四周的留白
map.put(EncodeHintType.MARGIN, 1);

    • 校正级别（二维码中最大坏像素点占比）：

      L - 7% M - 15% Q - 25% H - 30%

  5. 获取文本对象

    String url = req.getParameter("url");

  6. 创建 zxing 的核心对象

    MultiFormatWriter writer = new MultiFormatWriter();
    • MultiFormatWriter（多格式写入器）是一个便捷的二维码生成类，可以根据传入的 BarcodeFormat 参数，生成对应的二维码

  7. 传入二维码参数并获取宽高

    BitMatrix bitMatrix = writer.encode(url, BarcodeFormat.QR_CODE, 300, 300, map);
int height = bitMatrix.getHeight();
int width = bitMatrix.getWidth();
    • BarcodeFormat（码格式）是枚举类，用来指定二维码格式
      • QR_CODE：最常见二维码格式之一
      • AZTEC：高密度高可靠二维码格式
      • PDF_417：储存大量信息的二维码格式
      • DATA_MATRIX：一种小巧的二维码格/式
    • BitMatrix（位矩阵对象）是表示二维码矩阵的数据结构，实际上是一个紧凑型的布尔型二维数组，常用于将编码后的信息转化为矩阵类型，具有以下方法
      • getHeight()：获取矩阵高度
      • getWidth()：获取矩阵宽度
      • get(x, y)：获取指定位置的坐标值，值为true（黑色块）或 false（白色块）

  8. 生成二维码

    // 创建图片对象
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
// 遍历位矩阵对象，创建图像
for (int x = 0; x < width; x++) {
    for (int y = 0; y < height; y++) {
        image.setRGB(x, y, bitMatrix.get(x, y) ? 0xFF000000 : 0xFFFFFFFF);
    }
}

  9. 将图片返回到浏览器

    ServletOutputStream servletOutputStream = resp.getOutputStream();
ImageIO.write(image, "png", servletOutputStream);
servletOutputStream.flush();
servletOutputStream.close();

完整代码：

package com.qrcode.servlets;

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;
import jakarta.servlet.ServletException;
import jakarta.servlet.ServletOutputStream;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

@WebServlet("/generate")
public class GenerateQRCode extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        try {
            String url = req.getParameter("url");
            Map map = new HashMap();
            map.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
            map.put(EncodeHintType.CHARACTER_SET, "utf-8");
            map.put(EncodeHintType.MARGIN, 1);
            MultiFormatWriter writer = new MultiFormatWriter();
            BitMatrix bitMatrix = writer.encode(url, BarcodeFormat.QR_CODE, 300, 300, map);
            int height = bitMatrix.getHeight();
            int width = bitMatrix.getWidth();
            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);
                }
            }
            ServletOutputStream servletOutputStream = resp.getOutputStream();
            ImageIO.write(image, "png", servletOutputStream);
            servletOutputStream.flush();
            servletOutputStream.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

（2）带 logo 的二维码生成

  1. 修改前端页面 index.jsp

    <%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
  <head>
    <title>QRCode</title>
  </head>
  <body>
  <form action="/myqrcode/generate" method="post" enctype="multipart/form-data">
    输入文本：<input type="text" name="url" /><br />
    logo：<input type="file" name="logo" /><br />
    <input type="submit" value="生成二维码">
  </form>
  </body>
</html>

  2. 添加文件上传注释

    @MultipartConfig(fileSizeThreshold = 1024 * 1024 * 2, maxFileSize = 1024 * 1024 * 10, maxRequestSize = 1024 * 1024 * 100)

  3. 在 GenerateQRCode.java 中获取上传的 Logo

    Part logoPart = req.getPart("logo");
InputStream inputStream = logoPart.getInputStream();
Image logoImage = ImageIO.read(inputStream);

  4. 使用平滑缩放算法进行缩放

    int logoWidth = logoImage.getWidth(null);
int logoHeight = logoImage.getHeight(null);
logoWidth = logoWidth > 60 ? 60 : logoWidth;
logoHeight = logoHeight > 60 ? 60 : logoHeight;
Image logoImageScaledInstance = logoImage.getScaledInstance(logoWidth, logoHeight, Image.SCALE_SMOOTH);

  5. 获取 2D 画笔

    Graphics2D graphics2D = image.createGraphics();

  6. 指定开始作画的坐标

    int x = (300 - logoWidth) / 2;
int y = (300 - logoHeight) / 2;

  7. 绘制 Logo

    graphics2D.drawImage(logoImageScaledInstance, x, y, null);

    • 绘制圆角矩形

      Shape shape = new RoundRectangle2D.Float(x, y, logoWidth, logoHeight, 10, 10);
graphics2D.setStroke(new BasicStroke(4f));
graphics2D.draw(shape);

  8. 释放画笔

    graphics2D.dispose();

完整代码：

package com.qrcode.servlets;

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;
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.MultipartConfig;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import jakarta.servlet.http.Part;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.geom.RoundRectangle2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Map;

@WebServlet("/generate")
@MultipartConfig(fileSizeThreshold = 1024 * 1024 * 2, maxFileSize = 1024 * 1024 * 10, maxRequestSize = 1024 * 1024 * 100)
public class GenerateQRCode extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        try {
            String url = req.getParameter("url");
            Map map = new HashMap();
            map.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
            map.put(EncodeHintType.CHARACTER_SET, "utf-8");
            map.put(EncodeHintType.MARGIN, 1);
            MultiFormatWriter writer = new MultiFormatWriter();
            BitMatrix bitMatrix = writer.encode(url, BarcodeFormat.QR_CODE, 300, 300, map);
            int height = bitMatrix.getHeight();
            int width = bitMatrix.getWidth();
            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);
                }
            }
            Part logoPart = req.getPart("logo");
            InputStream inputStream = logoPart.getInputStream();
            Image logoImage = ImageIO.read(inputStream);
            int logoWidth = logoImage.getWidth(null);
            int logoHeight = logoImage.getHeight(null);
            logoWidth = Math.min(logoWidth, 60);
            logoHeight = Math.min(logoHeight, 60);
            Image logoImageScaledInstance = logoImage.getScaledInstance(logoWidth, logoHeight, Image.SCALE_SMOOTH);
            Graphics2D graphics2D = image.createGraphics();
            int x = (300 - logoWidth) / 2;
            int y = (300 - logoHeight) / 2;
            graphics2D.drawImage(logoImageScaledInstance, x, y, null);
            Shape shape = new RoundRectangle2D.Float(x, y, logoWidth, logoHeight, 10, 10);
            graphics2D.setStroke(new BasicStroke(4f));
            graphics2D.draw(shape);
            graphics2D.dispose();
            ImageIO.write(image, "png", resp.getOutputStream());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

0x03 qrcode

在 pom.xml 中添加依赖

<dependency>
    <groupId>com.github.liuyueyi.media</groupId>
    <artifactId>qrcode-plugin</artifactId>
    <version>2.5.2</version>
</dependency>

（1）黑白二维码

package com.qrcode.servlets;

import com.github.hui.quick.plugin.qrcode.wrapper.QrCodeGenWrapper;
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

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

@WebServlet("/generate")
public class GenerateQRCode extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        try {
            String url = req.getParameter("url");
            BufferedImage image = QrCodeGenWrapper.of(url).asBufferedImage();
            ImageIO.write(image, "png", resp.getOutputStream());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
  • of()：设置二维码内容
  • asBufferedImage()：生成二维码图片

（2）logo 二维码

package com.qrcode.servlets;

import com.github.hui.quick.plugin.qrcode.wrapper.QrCodeGenWrapper;
import com.github.hui.quick.plugin.qrcode.wrapper.QrCodeOptions;
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.MultipartConfig;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

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

@WebServlet("/generate")
@MultipartConfig(fileSizeThreshold = 1024 * 1024 * 2, maxFileSize = 1024 * 1024 * 10, maxRequestSize = 1024 * 1024 * 100)
public class GenerateQRCode extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        try {
            String url = req.getParameter("url");
            BufferedImage image = QrCodeGenWrapper.of(url)
                    .setLogo(req.getPart("logo").getInputStream())
                    .setLogoRate(7)
                    .setLogoStyle(QrCodeOptions.LogoStyle.ROUND)
                    .asBufferedImage();
            ImageIO.write(image, "png", resp.getOutputStream());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
  • setLogo()：设置 Logo 文件
  • setLogoRate(x)：设置 Logo 缩放比，logo 宽高占二维码宽高的 x 分之一
  • setLogoStyle()：设置 Logo 样式

（3）彩色二维码

BufferedImage image = QrCodeGenWrapper.of(url)
                    .setDrawPreColor(Color.BLUE)
                    .asBufferedImage();
  • setDrawPreColor()：设置前景色

（4）背景图二维码

BufferedImage image = QrCodeGenWrapper.of(url)
                    .setBgImg(req.getPart("logo").getInputStream())
                    .setBgOpacity(0.7F)
                    .asBufferedImage();
  • setBgImg()：设置背景图
  • setBgOpacity()：设置背景图透明度

（5）特殊形状二维码

BufferedImage image = QrCodeGenWrapper.of(url)
                    .setDrawEnableScale(true)
                    .setDrawStyle(QrCodeOptions.DrawStyle.DIAMOND)
                    .asBufferedImage();
  • setDrawEnableScale(true)：启用二维码绘制时的缩放功能
  • setDrawStyle()：设置绘制样式

（6）图片填充二维码

BufferedImage image = QrCodeGenWrapper.of(url)
                    .setErrorCorrection(ErrorCorrectionLevel.H)
                    .setDrawStyle(QrCodeOptions.DrawStyle.IMAGE)
                    .addImg(1, 1, req.getPart("logo").getInputStream())
                    .asBufferedImage();

  • setErrorCorrection()：设置二维码的错误校正级别

  • setDrawStyle()：绘制二维码时采用图片填充

  • addImg()：添加图片

-End-