程序员在上海之四

今天主要分享下前段时间做微信二维码的一些问题，我们都知道二维码的生产可以放到java后端，也可以直接使用jQuery插件jquery.qrcode.min.js来简单实现。下面简单分享下两种方式：

    1、java代码生产二维码。

       具体实现如下：

import java.awt.BasicStroke;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Shape;
import java.awt.geom.RoundRectangle2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.OutputStream;
import java.util.Hashtable;

import javax.imageio.ImageIO;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.DecodeHintType;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatReader;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.Result;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.common.HybridBinarizer;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
/**
*
* @author ****
*
*/
public class QRCodeUtil {
private static final String CHARSET = "utf-8";
private static final String FORMAT_NAME = "png";
// 二维码尺寸
private static final int QRCODE_SIZE = 300;
// LOGO宽度
private static final int WIDTH = 60;
// LOGO高度
private static final int HEIGHT = 60;

private static BufferedImage createImage(String content, String imgPath,
boolean needCompress) throws Exception {
Hashtable hints = new Hashtable();
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);
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)) {
return image;
}
// 插入图片
QRCodeUtil.insertImage(image, imgPath, needCompress);
return image;
}

private static void insertImage(BufferedImage source, String imgPath,
boolean needCompress) throws Exception {
File file = new File(imgPath);
if (!file.exists()) {
System.err.println(""+imgPath+"   该文件不存在！");
return;
}
Image src = ImageIO.read(new File(imgPath));
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();
}

/**
*
* @param content 二维码内容
* @param imgPath 读取图片路径 放到二维码中间
* @param destPath 存放图片路径
* @param needCompress
* @throws Exception
*/
public static void encode(String content, String imgPath, String destPath,
boolean needCompress) throws Exception {
BufferedImage image = QRCodeUtil.createImage(content, imgPath,
needCompress);
//mkdirs(destPath);
// String file = new Random().nextInt(99999999)+".png";
//String file = "qrcode.png";//生成二维码的图片
//    ImageIO.write(image, FORMAT_NAME, new File(destPath+"/"+file));
ImageIO.write(image, FORMAT_NAME, new File(destPath));
}

public static void mkdirs(String destPath) {
File file =new File(destPath);
//当文件夹不存在时，mkdirs会自动创建多层目录，区别于mkdir．(mkdir如果父目录不存在则会抛出异常)
if (!file.exists() && !file.isDirectory()) {
file.mkdirs();
}
}

public static void encode(String content, String imgPath, String destPath)
throws Exception {
QRCodeUtil.encode(content, imgPath, destPath, false);
}

public static void encode(String content, String destPath,
boolean needCompress) throws Exception {
QRCodeUtil.encode(content, null, destPath, needCompress);
}

public static void encode(String content, String destPath) throws Exception {
QRCodeUtil.encode(content, null, destPath, false);
}

public static void encode(String content, String imgPath,
OutputStream output, boolean needCompress) throws Exception {
BufferedImage image = QRCodeUtil.createImage(content, imgPath,
needCompress);
ImageIO.write(image, FORMAT_NAME, output);
}

public static void encode(String content, OutputStream output)
throws Exception {
QRCodeUtil.encode(content, null, output, false);
}

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 hints = new Hashtable();
hints.put(DecodeHintType.CHARACTER_SET, CHARSET);
result = new MultiFormatReader().decode(bitmap, hints);
String resultStr = result.getText();
return resultStr;
}

public static String decode(String path) throws Exception {
return QRCodeUtil.decode(new File(path));
}

public static void main(String[] args) throws Exception {
String text = "http://blog.csdn.net/tb176";
//下面读取和生产图片路径自己设置
 QRCodeUtil.encode(text, "C:\\Users\\****\\Desktop\\qrcode\\share-wx.png", "C:\\Users\\****\\Desktop\\qrcode\\qrcode.png", true);
}

}

辅助类如下：

  

import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;

import com.google.zxing.LuminanceSource;
/**
*
* @author ****
*
*/
public class BufferedImageLuminanceSource extends LuminanceSource {
private final BufferedImage image;
private final int left;
private final int top;

public BufferedImageLuminanceSource(BufferedImage image) {
this(image, 0, 0, image.getWidth(), image.getHeight());
}

public BufferedImageLuminanceSource(BufferedImage image, int left,
int top, int width, int height) {
super(width, height);

int sourceWidth = image.getWidth();
int sourceHeight = image.getHeight();
if (left + width > sourceWidth || top + height > sourceHeight) {
throw new IllegalArgumentException(
"Crop rectangle does not fit within image data.");
}

for (int y = top; y < top + height; y++) {
for (int x = left; x < left + width; x++) {
if ((image.getRGB(x, y) & 0xFF000000) == 0) {
image.setRGB(x, y, 0xFFFFFFFF); // = white
}
}
}

this.image = new BufferedImage(sourceWidth, sourceHeight,
BufferedImage.TYPE_BYTE_GRAY);
this.image.getGraphics().drawImage(image, 0, 0, null);
this.left = left;
this.top = top;
}

public byte[] getRow(int y, byte[] row) {
if (y < 0 || y >= getHeight()) {
throw new IllegalArgumentException(
"Requested row is outside the image: " + y);
}
int width = getWidth();
if (row == null || row.length < width) {
row = new byte[width];
}
image.getRaster().getDataElements(left, top + y, width, 1, row);
return row;
}

public byte[] getMatrix() {
int width = getWidth();
int height = getHeight();
int area = width * height;
byte[] matrix = new byte[area];
image.getRaster().getDataElements(left, top, width, height, matrix);
return matrix;
}

public boolean isCropSupported() {
return true;
}

public LuminanceSource crop(int left, int top, int width, int height) {
return new BufferedImageLuminanceSource(image, this.left + left,
this.top + top, width, height);
}

public boolean isRotateSupported() {
return true;
}

public LuminanceSource rotateCounterClockwise() {
int sourceWidth = image.getWidth();
int sourceHeight = image.getHeight();
AffineTransform transform = new AffineTransform(0.0, -1.0, 1.0,
0.0, 0.0, sourceWidth);
BufferedImage rotatedImage = new BufferedImage(sourceHeight,
sourceWidth, BufferedImage.TYPE_BYTE_GRAY);
Graphics2D g = rotatedImage.createGraphics();
g.drawImage(image, transform, null);
g.dispose();
int width = getWidth();
return new BufferedImageLuminanceSource(rotatedImage, top,
sourceWidth - (left + width), getHeight(), width);
}
}

以上是简单java实现二维码的生产，你可以通过扫描来查看是不是你想要的，下面来看下前段js怎么生成二维码的，这里我把工具改为WebStorm这样我们不需要每次都启动tomcat服了，它直接集成了这些功能，方便一些纯前端开发。最好参考《点击打开链接》因为这里说的太简单明了了。

接下来是关于文本内容过长导致二维码识别度降低的问题，我们这是会选择吧长链接转为短链接，具体可以参考《点击打开链接》下面是个人的测试案例

public static String Long2short(String url) throws IOException{

//生成短连接
String reqUrl = "http://980.so/api.php?url="+ URLEncoder.encode(url,"UTF-8");
logger.info("------转换之前的reqUrl="+reqUrl);
Map<String,String> map = new HashMap<String,String>();
String tinyUrl = GetRequest.getRequest(reqUrl,map);//http请求
if(tinyUrl != null && tinyUrl.startsWith("http://980.so/"))
{
url = tinyUrl;
}
logger.info("------转换之后的url="+url);
return url;
}
主函数也贴出来吧

public static void main(String[] args) throws IOException {
String url = "https://www.baidu.com/s?ie=utf-8&f=3&rsv_bp=1&tn=monline_dg&wd=980.so&oq=js%E7%94%9F%E6%88%90%E4%BA%8C%E7%BB%B4%E7%A0%81&rsv_pq=9f72e3720004d0d6&rsv_t=4723nWbFLUDh%2BxsJxCGBAJ%2BIyt%2F3OrwBNiGnGzQOpohNKYSqP9%2FbfPxFd9RIHq9s6A&rqlang=cn&rsv_enter=1&inputT=7382&rsv_sug3=15&rsv_sug1=15&rsv_sug7=100&bs=js%E7%94%9F%E6%88%90%E4%BA%8C%E7%BB%B4%E7%A0%81";
Long2short(url);
}

运行后，我们可以看到控制台结果

------转换之前的reqUrl=http://980.so/api.php?url=https%3A%2F%2Fwww.baidu.com%2Fs%3Fie%3Dutf-8%26f%3D3%26rsv_bp%3D1%26tn%3Dmonline_dg%26wd%3D980.so%26oq%3Djs%25E7%2594%259F%25E6%2588%2590%25E4%25BA%258C%25E7%25BB%25B4%25E7%25A0%2581%26rsv_pq%3D9f72e3720004d0d6%26rsv_t%3D4723nWbFLUDh%252BxsJxCGBAJ%252BIyt%252F3OrwBNiGnGzQOpohNKYSqP9%252FbfPxFd9RIHq9s6A%26rqlang%3Dcn%26rsv_enter%3D1%26inputT%3D7382%26rsv_sug3%3D15%26rsv_sug1%3D15%26rsv_sug7%3D100%26bs%3Djs%25E7%2594%259F%25E6%2588%2590%25E4%25BA%258C%25E7%25BB%25B4%25E7%25A0%2581
------转换之后的url=http://980.so/31pVn4从结果，我们可以看出效果。这时候你可以吧转换之后的url复制到浏览器地址栏看看效果了，是不是一样的咯~
今天到此了，后续……