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今天忙了一天的二维码,用了QRcode和ZXing两个开源包。结果发现
ZXing比QRcode更好用一些,它直接可以定义二维码生成图案的大小,而QRcode生成的二维码是根据二维码包含的内容多少来定的。所以生成的二维码图片大小不好确定。
下面主要说一下ZXing生成二维码的方法:
ZXing是google的开源资源,但是由于中国的某些原因使得访问谷歌的资源比较难,所以在网上找到了一个可以下载的连接:http://www.cr173.com/soft/65529.html
下载好需要的核心jar包后我们还需要下载一个可以将资源输出到文件或流的工具类MatrixToImageWriter,以下是百度到的源码:
1 package zxingTest; 2 import com.google.zxing.common.BitMatrix; 3 4 import javax.imageio.ImageIO; 5 import java.io.File; 6 import java.io.OutputStream; 7 import java.io.IOException; 8 import java.awt.image.BufferedImage; 9 10 11 public final class MatrixToImageWriter { 12 13 private static final int BLACK = 0xFF000000; 14 private static final int WHITE = 0xFFFFFFFF; 15 16 private MatrixToImageWriter() {} 17 18 19 public static BufferedImage toBufferedImage(BitMatrix matrix) { 20 int width = matrix.getWidth(); 21 int height = matrix.getHeight(); 22 BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); 23 for (int x = 0; x < width; x++) { 24 for (int y = 0; y < height; y++) { 25 image.setRGB(x, y, matrix.get(x, y) ? BLACK : WHITE); 26 } 27 } 28 return image; 29 } 30 31 32 public static void writeToFile(BitMatrix matrix, String format, File file) 33 throws IOException { 34 BufferedImage image = toBufferedImage(matrix); 35 if (!ImageIO.write(image, format, file)) { 36 throw new IOException("Could not write an image of format " + format + " to " + file); 37 } 38 } 39 40 41 public static void writeToStream(BitMatrix matrix, String format, OutputStream stream) 42 throws IOException { 43 BufferedImage image = toBufferedImage(matrix); 44 if (!ImageIO.write(image, format, stream)) { 45 throw new IOException("Could not write an image of format " + format); 46 } 47 } 48 49 }
接下来需要写一个测试类了,不过我已经测试过了,并进行了简单包装:
1 package zxingTest; 2 3 import java.io.File; 4 import java.io.IOException; 5 import java.io.OutputStream; 6 import java.util.Hashtable; 7 8 import com.google.zxing.BarcodeFormat; 9 import com.google.zxing.EncodeHintType; 10 import com.google.zxing.MultiFormatWriter; 11 import com.google.zxing.WriterException; 12 import com.google.zxing.common.BitMatrix; 13 14 public class TwoDimCodeUtil { 15 16 /** 17 * @Title: writeToFile 将二维码输出到文件 18 * @Description: 将二维码输出到文件 19 * @param fileName 文件名称 20 * @param contents 二维码包含的内容 21 * @param encodeType 字符编码 22 * @param imgSize 二维码生成图片大小,单位像素 23 * @param imgType 图片格式,jpg,png等 24 * @throws 25 */ 26 public static void writeToFile(String fileName,String contents,String encodeType,int imgSize,String imgType){ 27 Hashtable<EncodeHintType, String> hints = new Hashtable<EncodeHintType, String>(); 28 hints.put(EncodeHintType.CHARACTER_SET,encodeType); 29 BitMatrix matrix = null; 30 try { 31 matrix = new MultiFormatWriter().encode(contents,BarcodeFormat.QR_CODE, imgSize, imgSize, hints); 32 File file = new File(fileName); 33 MatrixToImageWriter.writeToFile(matrix, imgType, file); 34 } catch (WriterException e) { 35 e.printStackTrace(); 36 } catch (IOException e) { 37 e.printStackTrace(); 38 } 39 } 40 41 /** 42 * @Title: writeToFile 将二维码输出到流 43 * @Description: 将二维码输出到流 44 * @param outputStream 输出流 45 * @param contents 二维码包含的内容 46 * @param encodeType 字符编码 47 * @param imgSize 二维码生成图片大小 48 * @param imgType 图片格式,jpg,png等 49 * @throws 50 */ 51 public static void writeToStream(OutputStream outputStream,String contents,String encodeType,int imgSize,String imgType){ 52 Hashtable<EncodeHintType, String> hints = new Hashtable<EncodeHintType, String>(); 53 hints.put(EncodeHintType.CHARACTER_SET,encodeType); 54 BitMatrix matrix = null; 55 try { 56 matrix = new MultiFormatWriter().encode(contents,BarcodeFormat.QR_CODE, imgSize, imgSize, hints); 57 MatrixToImageWriter.writeToStream(matrix, imgType, outputStream); 58 } catch (WriterException e) { 59 e.printStackTrace(); 60 } catch (IOException e) { 61 e.printStackTrace(); 62 } 63 } 64 65 /** 66 * @Title: writeToFile 将二维码输出到流,默认编码utf-8,文件类型jpg 67 * @Description: 将二维码输出到流 68 * @param outputStream 输出流 69 * @param contents 二维码包含的内容 70 * @param imgSize 二维码生成图片大小 71 * @throws 72 */ 73 public static void writeToStream(OutputStream outputStream,String contents,int imgSize){ 74 TwoDimCodeUtil.writeToStream(outputStream, contents, "UTF-8", imgSize, "jpg"); 75 } 76 }
下面是调用的一个例子:
1 public void showQRCode(){ 2 HttpServletRequest request=this.getRequest(); 3 HttpServletResponse response=this.getResponse(); 4 response.setHeader("Pragma","No-cache"); 5 response.setHeader("Cache-Control","no-cache"); 6 response.setDateHeader("Expires", 0); 7 response.setContentType("image/jpeg"); 8 9 String content=request.getParameter("content"); 10 String widthstr= request.getParameter("width"); 11 int width=(widthstr==null||widthstr.equals(""))?140:Integer.valueOf(widthstr); 12 System.out.println(content); 13 try { 14 TwoDimCodeUtil.writeToStream(response.getOutputStream(), content, width); 15 } catch (IOException e) { 16 e.printStackTrace(); 17 } 18 }
页面调用:
<img src="/showQRCode.do?content=helloworld&width=140" />
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原文地址:http://www.cnblogs.com/andong2015/p/4316530.html