ZXing生成二维码

使用Google开源项目二维码读取和生成工具ZXing实现。

1、配置pom.xml文件：

<!-- QRCode 生成动态二维码 -->
        <dependency>  
            <groupId>com.google.zxing</groupId>
            <artifactId>core</artifactId>  
            <version>2.2</version>  
        </dependency>  
        <dependency>  
            <groupId>com.google.zxing</groupId>  
            <artifactId>javase</artifactId>  
            <version>2.2</version>  
        </dependency> 

2、在web.xml中配置请求的servlet:

<!-- QRCode -->
    <servlet>
          <servlet-name>qrCode</servlet-name>
          <servlet-class>com.fan.servlet.BarCode2DServlet</servlet-class>
      </servlet>
      <servlet-mapping>
          <servlet-name>qrCode</servlet-name>
          <url-pattern>/qrCode</url-pattern>
      </servlet-mapping>

3、servlet代码：

@Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        OutputStream stream = null;
        try {
            stream = resp.getOutputStream();
            String  filePath = getServletConfig().getServletContext().getRealPath("/");
            QRCodeUtil.encode("根据什么生成二维码", "嵌入图片的地址", stream, true, filePath); 
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (stream != null) {
                stream.flush(); 
                stream.close(); 
            } 
        } 
    } 
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        this.doGet(req, resp);
    }

4、生成二维码的工具类QRCodeUtil.java：

/**
 * 二维码工具类
 * 
 */
public class QRCodeUtil {

    private static final String CHARSET = "utf-8";
    private static final String FORMAT_NAME = "JPG";
    // 二维码尺寸
    private static final int QRCODE_SIZE = 200;
    // LOGO宽度
    private static final int WIDTH = 40;
    // LOGO高度
    private static final int HEIGHT = 40;

    private static BufferedImage createImage(String content, String imgPath,
            boolean needCompress) throws Exception {
        Hashtable<EncodeHintType, Object> hints = new Hashtable<EncodeHintType, Object>();
        hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
        hints.put(EncodeHintType.CHARACTER_SET, CHARSET);
        hints.put(EncodeHintType.MARGIN, 1);
        BitMatrix bitMatrix = new MultiFormatWriter().encode(content,
                BarcodeFormat.QR_CODE, QRCODE_SIZE, QRCODE_SIZE, hints);
        // 去掉白边
        int[] rec = bitMatrix.getEnclosingRectangle();  
        if(rec != null){
            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); 
                    } 
                }  
            }  
        }

        int width = bitMatrix.getWidth();
        int height = bitMatrix.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, bitMatrix.get(x, y) ? 0xFF000000 : 0xFFFFFFFF);
            }
        }
        if (imgPath == null || "".equals(imgPath)) {
            Log.info("no logo success：");
            return image;
        }
        
        // 配置了logo路径时插入图片
        QRCodeUtil.insertImage(image, imgPath, needCompress);
        Log.info("have logo success");
        return image;
    }

    /**
     * 插入LOGO
     */
    private static void insertImage(BufferedImage source, String imgPath, boolean needCompress) throws Exception {
        //new一个URL对象  
        URL url = new URL(imgPath);  
        //打开链接  
        HttpURLConnection conn = (HttpURLConnection)url.openConnection();  
        //设置请求方式为"GET"  
        conn.setRequestMethod("GET");  
        //超时响应时间为5秒  
        conn.setConnectTimeout(5 * 1000);  
        //通过输入流获取图片数据  
        InputStream inStream = conn.getInputStream();  
        //得到图片的二进制数据，以二进制封装得到数据，具有通用性  
        byte[] data = readInputStream(inStream);  
        //创建文件用于暂存公司LOGO
        File tmpFile = createTmpFile();
        //new一个文件对象用来保存图片，默认保存当前工程根目录  
        //创建输出流  
        FileOutputStream outStream = new FileOutputStream(tmpFile);  
        //写入数据  
        outStream.write(data);
        //关闭输出流  
        outStream.close();  
        Image src = ImageIO.read(tmpFile);
        if(src != null){
            int width = src.getWidth(null);
            int height = src.getHeight(null);
            if (needCompress) { // 压缩LOGO
                if (width > WIDTH) {
                    width = WIDTH;
                }
                if (height > HEIGHT) {
                    height = HEIGHT;
                }
                Image image = src.getScaledInstance(width, height,
                        Image.SCALE_SMOOTH);
                BufferedImage tag = new BufferedImage(width, height,
                        BufferedImage.TYPE_INT_RGB);
                Graphics g = tag.getGraphics();
                g.drawImage(image, 0, 0, null); // 绘制缩小后的图
                g.dispose();
                src = image;
            }
            // 插入LOGO
            Graphics2D graph = source.createGraphics();
            int x = (QRCODE_SIZE - width) / 2;
            int y = (QRCODE_SIZE - height) / 2;
            graph.drawImage(src, x, y, width, height, null);
            Shape shape = new RoundRectangle2D.Float(x, y, width, width, 6, 6);
            graph.setStroke(new BasicStroke(3f));
            graph.draw(shape);
            graph.dispose();
        }
    }
    
    private static File createTmpFile(){
        String path = "/tmpLogo";
        File f = new File(path);
        if(!f.exists()){
            f.mkdirs();
        } 
        // fileName表示你创建的文件名；为txt类型；
        String fileName="zxing_tmp.png";
        File tmpFile = new File(f,fileName);
        if(!tmpFile.exists()){
            try {
                tmpFile.createNewFile();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return tmpFile;
    }
    
    
    /**
     * 把文件读出来
     */
   public static byte[] readInputStream(InputStream inStream) throws Exception{  
        ByteArrayOutputStream outStream = new ByteArrayOutputStream();  
        //创建一个Buffer字符串  
        byte[] buffer = new byte[1024];  
        //每次读取的字符串长度，如果为-1，代表全部读取完毕  
        int len = 0;  
        //使用一个输入流从buffer里把数据读取出来  
        while( (len=inStream.read(buffer)) != -1 ){  
            //用输出流往buffer里写入数据，中间参数代表从哪个位置开始读，len代表读取的长度  
            outStream.write(buffer, 0, len);  
        }  
        //关闭输入流  
        inStream.close();  
        //把outStream里的数据写入内存  
        return outStream.toByteArray();  
    }

    /**
     * 生成二维码(内嵌LOGO)
     */
    public static void encode(String content, String imgPath, HttpServletResponse resp, boolean needCompress) throws Exception {
        BufferedImage image = QRCodeUtil.createImage(content, imgPath, needCompress);
        ImageIO.write(image, FORMAT_NAME, resp.getOutputStream());
    }

    /**
     * 生成二维码(内嵌LOGO)
     */
    public static void encode(String content, String imgPath, HttpServletResponse resp)
            throws Exception {
        QRCodeUtil.encode(content, imgPath, resp, false);
    }

    /**
     * 生成二维码
     */
    public static void encode(String content, HttpServletResponse resp,
            boolean needCompress) throws Exception {
        QRCodeUtil.encode(content, null, resp, needCompress);
    }

    /**
     * 生成二维码
     */
    public static void encode(String content, HttpServletResponse resp) throws Exception {
        QRCodeUtil.encode(content, null, resp, false);
    }

    /**
     * 生成二维码(内嵌LOGO)
     */
    public static void encode(String content, String imgPath,
            OutputStream output, boolean needCompress, String realPath) throws Exception {
        BufferedImage image = QRCodeUtil.createImage(content, imgPath,
                needCompress);
        
        File file =new File(realPath + "res/qrcodeTmp");
        if (!file.exists() && !file.isDirectory()) {
            file.mkdirs();
        }
        ImageIO.setCacheDirectory(file);
        
        ImageIO.write(image, FORMAT_NAME, output);
    }
    
    /**
     * 生成二维码
     */
    public static void encode(String content, OutputStream output)
            throws Exception {
        QRCodeUtil.encode(content, null, output, false, "/");
    }

    /**
     * 解析二维码
     */
    public static String decode(File file) throws Exception {
        BufferedImage image;
        image = ImageIO.read(file);
        if (image == null) {
            return null;
        }
        BufferedImageLuminanceSource source = new BufferedImageLuminanceSource(
                image);
        BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
        Result result;
        Hashtable<DecodeHintType, Object> hints = new Hashtable<DecodeHintType, Object>();
        hints.put(DecodeHintType.CHARACTER_SET, CHARSET);
        result = new MultiFormatReader().decode(bitmap, hints);
        String resultStr = result.getText();
        return resultStr;
    }

    /**
     * 解析二维码
     */
    public static String decode(String path) throws Exception {
        return QRCodeUtil.decode(new File(path));
    }
}

5、页面上如何请求：

<img src="${base}/qrCode">

这样就可以把生成的二维码到指定<img>标签的位置。

注意：ImageIO.write(image, FORMAT_NAME, resp.getOutputStream()); 的write方法会默认找temp目录，如果服务器上没有temp目录则图片展示不出来，且报错Can't create cache file!具体报错信息如下：

javax.imageio.IIOException: Can't create output stream!
        at javax.imageio.ImageIO.write(ImageIO.java:1560)
        at com.fan.util.QRCodeUtil.encode(QRCodeUtil.java:237)
        at com.fan.BarCode2DServlet.doGet(BarCode2DServlet.java:44)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:620)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
        at com.lenovo.moc.portal.controller.SecurityFilter.doFilter(SecurityFilter.java:43)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
        at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
        at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)
        at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1074)
        at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
        at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2466)
        at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2455)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        at java.lang.Thread.run(Thread.java:662)
Caused by: javax.imageio.IIOException: Can't create cache file!
        at javax.imageio.ImageIO.createImageOutputStream(ImageIO.java:397)
        at javax.imageio.ImageIO.write(ImageIO.java:1558)
        ... 28 more
Caused by: java.io.IOException: No such file or directory
        at java.io.UnixFileSystem.createFileExclusively(Native Method)
        at java.io.File.checkAndCreate(File.java:1705)
        at java.io.File.createTempFile0(File.java:1726)
        at java.io.File.access$100(File.java:120)
        at java.io.File$1.createTempFile(File.java:1955)
        at sun.misc.IOUtils.createTempFile(IOUtils.java:88)
        at javax.imageio.stream.FileCacheImageOutputStream.<init>(FileCacheImageOutputStream.java:71)
        at com.sun.imageio.spi.OutputStreamImageOutputStreamSpi.createOutputStreamInstance(OutputStreamImageOutputStreamSpi.java:50)
        at javax.imageio.ImageIO.createImageOutputStream(ImageIO.java:393)

为什么呢？源码如下：在默认的temp下生成一个imgio**************.tmp的临时文件然后删除。

 

 

怎样让他缓存在自己想要的目录下呢？使用ImageIO中的cacheDirectory属性来设置即可。