java中二维码的使用（一）生成二维码

生活中随处可见的二维码大家都不陌生，java中常用的是矩阵式二维码QRCode，生成QRCode有很多现成的工具，这里简单记一下。

1.QRCode，这个是日本人写的，下载QRCode.jar就可以用了

package com.util;

import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.io.UnsupportedEncodingException;

import javax.imageio.ImageIO;

import com.swetake.util.Qrcode;

public class QrCodeUtil {
    /**
     * 生成二维码图片
     * @param content 二维码内容
     * @param imgPath 二维码图片的保存路径
     */
    public static void getQrcodeImg(String content,String imgPath){
        int width=140;
        int height=140;
        //实例化Qrcode
        Qrcode qrcode=new Qrcode();
        //设置二维码的排错率L(7%) M(15%) Q(25%) H(35%)
        qrcode.setQrcodeErrorCorrect('M');
        qrcode.setQrcodeEncodeMode('B');        
        //设置二维码尺寸(1~49)
        qrcode.setQrcodeVersion(7);
        //设置图片尺寸
        BufferedImage bufImg=new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
        
        //绘制二维码图片
        Graphics2D gs=bufImg.createGraphics();
        //设置二维码背景颜色
        gs.setBackground(Color.WHITE);
        //创建一个矩形区域
        gs.clearRect(0, 0, width, height);
        //设置二维码的图片颜色值 黑色
        gs.setColor(Color.BLACK);
        
        //获取内容的字节数组,设置编码集
        try {
            byte[] contentBytes=content.getBytes("utf-8");
            int pixoff=2;
            //输出二维码
            if(contentBytes.length>0&&contentBytes.length<120){
                boolean[][] codeOut=qrcode.calQrcode(contentBytes);
                for(int i=0;i<codeOut.length;i++){
                    for(int j=0;j<codeOut.length;j++){
                        if(codeOut[j][i]){
                            gs.fillRect(j*3+pixoff, i*3+pixoff, 3, 3);
                        }
                    }
                }    
            }
            gs.dispose();
            bufImg.flush();
            //生成二维码图片
            File imgFile=new File(imgPath);
            ImageIO.write(bufImg, "png", imgFile);
            
            System.out.println("二维码生成成功！");
            
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    public static void main(String[] args) {
        getQrcodeImg("傻狗", "E:\\qrcode.png");
    }
}

2.ZXing，google的开源项目，除了写二维码条形码一维码什么的也能写

package com.util;

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

import javax.imageio.ImageIO;

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

public class ZxingUtil {
        private static final int BLACK = 0xFF000000;  
        private static final int WHITE = 0xFFFFFFFF;  
         
        private ZxingUtil() {  
        }  
      
        public static BufferedImage toBufferedImage(BitMatrix matrix) {  
            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;  
        }  
      
        public static void writeToFile(BitMatrix matrix, String format, File file) throws IOException {  
            BufferedImage image = toBufferedImage(matrix);  
            if (!ImageIO.write(image, format, file)) {  
                throw new IOException("Could not write an image of format " + format + " to " + file);  
            }  
        }  
      
        public static void writeToStream(BitMatrix matrix, String format, OutputStream stream) throws IOException {  
            BufferedImage image = toBufferedImage(matrix);  
            if (!ImageIO.write(image, format, stream)) {  
                throw new IOException("Could not write an image of format " + format);  
            }  
        }  
        
        public static void main(String[] args) throws WriterException, IOException {
            String text = "榆次丶吴彦祖"; // 二维码内容  
            int width = 300; // 二维码图片宽度  
            int height = 300; // 二维码图片高度  
            String format = "gif";// 二维码的图片格式  
              
            Hashtable<EncodeHintType, String> hints = new Hashtable<EncodeHintType, String>();  
            hints.put(EncodeHintType.CHARACTER_SET, "utf-8");   // 内容所使用字符集编码  
              
            BitMatrix bitMatrix = new MultiFormatWriter().encode(text, BarcodeFormat.QR_CODE, width, height, hints);  
            // 生成二维码  
            File outputFile = new File("E:" + File.separator + "zxing.jpg");  
            writeToFile(bitMatrix, format, outputFile);
            System.out.println("生成成功");
        }
}

3.jquery.qrcode插件，这个也很简单，网页端生成图片，资源消耗小

页面引入js文件

<script type="text/javascript" src="<%=basePath %>/js/jquery.min.js"></script>
<script type="text/javascript" src="<%=basePath %>/js/jquery.qrcode.min.js"></script>```
写js

('#qrcode').qrcode("http://www.baidu.com");
}); ```
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