Spring 使用<img>展示二维码标签

最新推荐文章于 2024-10-16 00:28:29 发布

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文章发表1周内为内容优化高峰期，后续会根据认知迭代继续做完善补充。

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本文介绍如何在Spring环境中生成带有或不带Logo的二维码，并提供在线展示及下载功能。

前言

本文实现 Spring 环境前端访问 <img>,访问后台，展示出一个二维码

出于简化的考虑，本文的二维码在后台固定内容，大小等参数。

1、之前写过一篇文章：关于二维码生成的3种方式

但是其中关于在线生成二维码的方式不是Spring的，所以写本文算是以后可以直接使用代码了

http://blog.youkuaiyun.com/bestcxx/article/details/53116996

2、Spring 基本环境搭建

（MAVEN）Spring MVC 入门之页面跳转

3、pom.xml 增加zxing依赖

 <!-- 字符串生成二维码 -->
	    <dependency>
		    <groupId>com.google.zxing</groupId>
		    <artifactId>core</artifactId>
		    <version>3.3.0</version>
		</dependency>

4、前台页面

logoFlag=yes 则二维码会额外增加logo,logo是20乘以20

<br><br>
	<img alt="纯二维码测试" src="<%=basePath %>/qrCode/qrCode?logoFlag=no">
	<br><br>
	<img alt="二维码增加图标测试" src="<%=basePath %>/qrCode/qrCode?logoFlag=yes">

5、后台Controller

import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Hashtable;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.common.BitMatrix;

@Controller
@RequestMapping("/qrCode")
public class RqCodeController {
	
	/**
	 * 
	 * @param request
	 * @param response
	 * @param logoFlag  是否需要为二维码增加logo  yes:增加，no：不增加
	 * @throws IOException
	 */
	@GetMapping("/qrCode")
	public void getQrCode(HttpServletRequest request,HttpServletResponse response,String logoFlag) throws IOException{
		response.setContentType("image/jpeg");
		OutputStream out = response.getOutputStream();
		response.setHeader("Pragma","No-cache"); 
		response.setHeader("Cache-Control","no-cache"); 
		response.setDateHeader("Expires", 0);
		
		 String url="http://www.bestcxx.cn";
		 int width = 180;   
		 int height = 180;
		 String format = "png";
		 String logoPath="D://1.PNG";//logo的地址
	     Hashtable hints= new Hashtable();   
	     hints.put(EncodeHintType.CHARACTER_SET, "utf-8");   
	     BitMatrix bitMatrix; 
	     
	     try {
				
				bitMatrix = new MultiFormatWriter().encode(url, BarcodeFormat.QR_CODE, width, height,hints);
				//去白边
				int[] rec = bitMatrix.getEnclosingRectangle();  
		     	int resWidth = rec[2] + 1;  
		     	int resHeight = rec[3] + 1;
		     	BitMatrix resMatrix = new BitMatrix(resWidth, resHeight);  
		     	resMatrix.clear();  
		     	for (int i = 0; i < resWidth; i++) {  
		     	    for (int j = 0; j < resHeight; j++) {  
		     	        if (bitMatrix.get(i + rec[0], j + rec[1])) { 
		     	             resMatrix.set(i, j); 
		     	        } 
		     	    }  
		     	}
		     	BufferedImage image = toBufferedImage(resMatrix);
		     	
		     	//增加图标
		     	if("yes".equals(logoFlag)){//标志位为yes 则增加图标
					BufferedImage logo = ImageIO.read(new File(logoPath));
					Graphics2D g = image.createGraphics();
					// logo宽高
					width =20;
					height =20;
					
					// logo起始位置，此目的是为logo居中显示
					int x = (image.getWidth() - width) / 2;
					int y = (image.getHeight() - height) / 2;
					g.drawImage(logo, x, y, null);
					g.dispose();
		     	}
		     	
		     	ImageIO.write(image, "PNG", out); 

			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}   
	}
	
	
	
	 public static BufferedImage toBufferedImage(BitMatrix matrix) {
			int BLACK = 0xFF000000;
			int WHITE = 0xFFFFFFFF;
			int width = matrix.getWidth();
			int height = matrix.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, matrix.get(x, y) ? BLACK : WHITE);
			 	}
			}
			return image;
		}

}

6、效果

+2017-11-28+

我们可以将这个方法优化为工具类，不直接对外开放，有修改，这样可以提供二维码在线展示或者下载

import java.awt.Graphics2D;  
import java.awt.image.BufferedImage;  
import java.io.File;  
import java.io.IOException;  
import java.io.OutputStream;
import java.util.Date;
import java.util.Hashtable;  
  
import javax.imageio.ImageIO;  
import javax.servlet.http.HttpServletRequest;  
import javax.servlet.http.HttpServletResponse;  
  
import com.google.zxing.BarcodeFormat;  
import com.google.zxing.EncodeHintType;  
import com.google.zxing.MultiFormatWriter;  
import com.google.zxing.common.BitMatrix;

/**
 * 生成二维码的工具类
 * @author Administrator
 *
 */
public class RqCodeUtil {

	/** 
     *  
     * @param request 
     * @param response 
     * @param logoFlag  是否需要为二维码增加logo  yes:增加，no：不增加 
     * @param typeFlag  1-图片下载 ，2-图片在线展示
     * @param fielName  图片名称
     * @throws IOException 
     */  
    public void getQrCode(HttpServletRequest request,HttpServletResponse response,
    		String logoFlag,String url,String typeFlag,String fielName) throws IOException{  
        if("1".equals(typeFlag)){
        	response.setContentType("application/octet-stream"); //图片下载        	
        }else{
        	response.setContentType("image/jpeg"); //图片展示
        }
        
        OutputStream out = response.getOutputStream();  
        response.setHeader("Pragma","No-cache");   
        response.setHeader("Cache-Control","no-cache");   
        response.setDateHeader("Expires", 0);  
        response.addHeader("Content-Disposition","attachment;filename="+new String((fielName+new Date().getTime()+".png").getBytes()));//设置header，文件名字  
       
	    int width = 180;     
	    int height = 180;  
	    String format = "png";  
	    String logoPath="D://1.PNG";//logo的地址  
	    Hashtable hints= new Hashtable();     
	    hints.put(EncodeHintType.CHARACTER_SET, "utf-8");     
	    BitMatrix bitMatrix;   
           
        try {  
                  
            bitMatrix = new MultiFormatWriter().encode(url, BarcodeFormat.QR_CODE, width, height,hints);  
            //去白边  
            int[] rec = bitMatrix.getEnclosingRectangle();    
            int resWidth = rec[2] + 1;    
            int resHeight = rec[3] + 1;  
            BitMatrix resMatrix = new BitMatrix(resWidth, resHeight);    
            resMatrix.clear();    
            for (int i = 0; i < resWidth; i++) {    
                for (int j = 0; j < resHeight; j++) {    
                    if (bitMatrix.get(i + rec[0], j + rec[1])) {   
                         resMatrix.set(i, j);   
                    }   
                }    
            }  
            BufferedImage image = toBufferedImage(resMatrix);  
              
            //增加图标  
            if("yes".equals(logoFlag)){//标志位为yes 则增加图标  
                BufferedImage logo = ImageIO.read(new File(logoPath));  
                Graphics2D g = image.createGraphics();  
                // logo宽高  
                width =20;  
                height =20;  
                  
                // logo起始位置，此目的是为logo居中显示  
                int x = (image.getWidth() - width) / 2;  
                int y = (image.getHeight() - height) / 2;  
                g.drawImage(logo, x, y, null);  
                g.dispose();  
            }  
              
            ImageIO.write(image, "PNG", out);   
  
            } catch (Exception e) {  
                // TODO Auto-generated catch block  
            e.printStackTrace();  
        }     
    }  
     
     public static BufferedImage toBufferedImage(BitMatrix matrix) {  
        int BLACK = 0xFF000000;  
        int WHITE = 0xFFFFFFFF;  
        int width = matrix.getWidth();  
        int height = matrix.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, matrix.get(x, y) ? BLACK : WHITE);  
            }  
        }  
        return image;  
     }  
  
}

+20190313如果要指定图片名称+

response.setHeader("Content-Disposition", "attachment;filename=名字.jpg");