Java将字符串生成二维码并下载图片

曾经终败给现在 2023-02-25 02:13 22阅读 0赞

## 前言 ##

今天记录一下最近写的下载二维码的代码，实现类似微信样式的二维码。主要是先生成二维码，再用Java的Graphics2D画图添加边框样式和文字，最后下载图片。

## 具体实现 ##

1.  添加依赖包

<dependency>
    		    <groupId>com.google.zxing</groupId>
    		    <artifactId>core</artifactId>
    		    <version>3.3.0</version>
    		</dependency>
    		<dependency>
    		    <groupId>com.google.zxing</groupId>
    		    <artifactId>javase</artifactId>
    		    <version>3.3.0</version>
    		</dependency>

1.  代码引入包

import java.awt.AlphaComposite;
    import java.awt.Color;
    import java.awt.Font;
    import java.awt.Graphics2D;
    import java.awt.image.BufferedImage;
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileOutputStream;
    import java.io.OutputStream;
    import java.net.URLEncoder;
    import java.util.HashMap;
    import java.util.Map;
    
    import javax.imageio.ImageIO;
    import javax.servlet.http.HttpServletResponse;
    
    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;

1.  具体方法代码

public void exportQuickResponseCode(HttpServletRequest request, HttpServletResponse response) throws Exception{
    		String msg = "好孩子，你还扫这个码";
            String filename = "123.png";
            String path = "D:/1000/" + filename;
            String orgText = "中华人民共和国人民的二维码";
            String goodsNameText = "送你一亿二维码";
            try {
                File file=new File(path);
                OutputStream ous=new FileOutputStream(file);
                Map<EncodeHintType,String> map =new HashMap<EncodeHintType, String>();
                //设置编码 EncodeHintType类中可以设置MAX_SIZE， ERROR_CORRECTION，CHARACTER_SET，DATA_MATRIX_SHAPE，AZTEC_LAYERS等参数
                map.put(EncodeHintType.CHARACTER_SET,"UTF-8");
                map.put(EncodeHintType.MARGIN,"2");
                //生成二维码
                BitMatrix bitMatrix = new MultiFormatWriter().encode(msg, BarcodeFormat.QR_CODE,600,600,map);
                MatrixToImageWriter.writeToStream(bitMatrix,"png",ous);
                
                // 绘制图片
                BufferedImage backgroundImage = new BufferedImage(1000, 1100, BufferedImage.TYPE_INT_RGB);
                BufferedImage image = ImageIO.read(file);
                Graphics2D rng=backgroundImage.createGraphics();
                rng.setColor( new Color(30, 171, 58));//设置笔刷颜色
                rng.fillRect(0,0,1000,1100);
                rng.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP));
                rng.drawImage(image,200,250,600,600,null);
                // 绘制文字
                rng.setColor(Color.white);
                rng.setFont(new Font("黑体",Font.BOLD,46));
                rng.drawString(orgText,(1000-13*46)/2,220);
                rng.drawString(goodsNameText,(1000-7*46)/2,900);
                
                rng.dispose();
                image = backgroundImage;
                image.flush();
                ImageIO.write(image, "png", file);
                
                // 以下是下载图片
    			// 当文件名不是英文名的时候，最好使用url解码器去编码一下，
    			filename=URLEncoder.encode(filename,"UTF-8");
    			// 将响应的类型设置为图片
    			response.setContentType("image/png");
    			response.setHeader("Content-Disposition", "attachment;filename=" + filename);
    			FileInputStream fileInputStream = new FileInputStream(file);
    			OutputStream out = response.getOutputStream();
    			int len = 0;
    			byte[] by = new byte[1024*10];
    			while ((len = fileInputStream.read(by))>0){
    				out.write(by,0,len);
    			}
    			out.close();
    			fileInputStream.close();
            }catch (Exception e) {
                e.printStackTrace();
            }
    	}

## 后记 ##

代码分为三部分，第一部分生成二维码，如果只需要二维码，第一部分就足够了，第二部分是绘制外边绿色边框和文字，第三部分是下载图片。

最终图片  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM2NjM3NzA1_size_16_color_FFFFFF_t_70]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM2NjM3NzA1_size_16_color_FFFFFF_t_70]: /images/20230209/15757b8072cf43e2afc9bef319a2a0ab.png