AgainFly当根据需要，我们需要在页面上生成动态可变的二维码的时候，可以根据本例做为参考，本例使用Servlet做范例，使用的是Google的zxing二维码工具。
更新代码：2016-10-19
1.重构了重载
2.现在二维码是彩色的！
首先，我们需要写两个工具类，外加一个Servlet，总共三个类。
第一个：BufferedImageLuminanceSource.java
package com.againfly.qrcode;
import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import com.google.zxing.LuminanceSource;
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);
}
}
第二个：QRCodeUtil.java
package com.againfly.qrcode;
import java.awt.BasicStroke;
import java.awt.Color;
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.IOException;
import java.util.HashMap;
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.common.BitMatrix;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
public class QRCodeUtil {
public static void main(String[] args) throws IOException {
String charset = "utf-8";
String text = "http://www.againfly.com/";
String insertImg = "D://q.png";
BufferedImage qr = null;
try {
QRCodeUtil.CHARSET = charset;
qr = QRCodeUtil.createImage(text, 300, insertImg, 62);
} catch (Exception e) {
e.printStackTrace();
}
ImageIO.write(qr, "png", new File("D://q.jpg"));
}
private static String CHARSET = "utf-8";
// 二维码尺寸
private static final int QRCODE_SIZE = 300;
public static BufferedImage createImage(String content) throws Exception{
return createImage(content, "");
}
public static BufferedImage createImage(String content, String logoPath) throws Exception{
File logoFile = new File(logoPath);
return createImage(content, QRCODE_SIZE, logoFile);
}
public static BufferedImage createImage(String content, File logoFile) throws Exception{
return createImage(content, QRCODE_SIZE, logoFile);
}
public static BufferedImage createImage(String content, int size, File logoFile) throws Exception{
return createImage(content, size, logoFile, (int)(size / 5));
}
public static BufferedImage createImage(String content, int size, String logoPath, int logoSize)
throws Exception {
return createImage(content, size, new File(logoPath), logoSize);
}
public static BufferedImage createImage(String content, int size, File logoFile, int logoSize)
throws Exception {
Map<EncodeHintType, Object> hints = new HashMap<EncodeHintType, Object>();
hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.Q);
hints.put(EncodeHintType.CHARACTER_SET, CHARSET);
hints.put(EncodeHintType.MARGIN, 1);
BitMatrix bitMatrix = new MultiFormatWriter().encode(content,
BarcodeFormat.QR_CODE, size, 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++) {
//自定义二维码颜色和背景颜色
int num1 = (int) (50 - (50.0 - 13.0) / bitMatrix.getHeight() * (y + 1));
int num2 = (int) (165 - (165.0 - 72.0) / bitMatrix.getHeight() * (y + 1));
int num3 = (int) (162 - (162.0 - 107.0) / bitMatrix.getHeight() * (y + 1));
Color color = new Color(num1, num2, num3);
int colorInt = color.getRGB();
//image.setRGB(x, y, bitMatrix.get(x, y) ? 0xFF000000 : 0xFFFFFFFF);
image.setRGB(x, y, bitMatrix.get(x, y) ? colorInt : 0xFFFFFFFF);
}
}
// 插入logo图片
if (null != logoFile) {
QRCodeUtil.insertImage(image, size, logoFile, logoSize);
}
return image;
}
private static void insertImage(BufferedImage source, int size, File logoFile, int logoSize)
throws Exception {
if (!logoFile.exists()) {
System.err.println("" + logoFile +" 该文件不存在！");
return;
}
Image src = ImageIO.read(logoFile);
int width = src.getWidth(null);
int height = src.getHeight(null);
{ // 压缩LOGO
if (width > logoSize) {
width = logoSize;
}
if (height > logoSize) {
height = logoSize;
}
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;
}
Graphics2D graph = source.createGraphics();// 插入LOGO
int x = (size - width) / 2;
int y = (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();
}
}
第三个Servlet：QRDemo.java
package com.againfly.demo;
import java.awt.image.BufferedImage;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.againfly.qrcode.QRCodeUtil;
public class QRDemo extends HttpServlet {
@Override
protected void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("image/png");
response.setHeader("Pragma", "no-cache");//禁止图像缓存。
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
String formatName = "PNG";
String charset = "utf-8";
String text = "http://www.againfly.com";
String insertImg = "/MYOTee.JPG";
BufferedImage qr = null;
try {
qr = QRCodeUtil.createImage(text, insertImg);
} catch (Exception e) {
e.printStackTrace();
}
ImageIO.write(qr, formatName, response.getOutputStream());
}
}
////////////////////////////////////////////_/
这是彩色的图：
效果图：
2016-10-19
补充内容：从webroot下获取File文件
public static File getRootFile(String src) {
ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
if (classLoader == null) {
classLoader = ClassLoader.getSystemClassLoader();
}
java.net.URL url = classLoader.getResource("");
String ROOT_CLASS_PATH = url.getPath() + "/";
File rootFile = new File(ROOT_CLASS_PATH);
String WEB_INFO_DIRECTORY_PATH = rootFile.getParent() + "/";
File webInfoDir = new File(WEB_INFO_DIRECTORY_PATH);
String SERVLET_CONTEXT_PATH = webInfoDir.getParent() + "/";
// 这里 SERVLET_CONTEXT_PATH 就是WebRoot的路径
String path = SERVLET_CONTEXT_PATH + "/" + src;
path = path.replaceAll("%20", " ");
return new File(path);
}
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