Java生成、解析二维码
今天遇到需求，使用Java生成二维码图片，网搜之后，大神们早就做过，个人总结一下。
目标：借助Google提供的ZXing Core工具包，使用Java语言实现二维码的生成和解析。
步骤如下：
1.maven项目中，pom.xml中引入ZXing Core工具包：
com.google.zxing core 3.3.0 2.首先，需要引出Google提供MatrixToImageWriter类，它是实现生成二维码图片的核心类：
import com.google.zxing.common.BitMatrix;import javax.imageio.ImageIO;
import java.io.File;
import java.io.OutputStream;
import java.io.IOException;
import java.awt.image.BufferedImage;/*** 用于二维码的生成，由Google提供。** Created by Eric on 2017/2/15.*/
public final class MatrixToImageWriter {private static final int BLACK = 0xFF000000;private static final int WHITE = 0xFFFFFFFF;private MatrixToImageWriter() {}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);}}再次，需要引出Google提供BufferedImageLuminanceSource类，它是实现解析二维码图片的核心类：
import com.google.zxing.LuminanceSource;import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;/*** 用于二维码的解析，由Google提供。** Created by Eric on 2017/2/15.*/
public final 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;}@Overridepublic 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;}@Overridepublic 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;}@Overridepublic boolean isCropSupported() {return true;}@Overridepublic LuminanceSource crop(int left, int top, int width, int height) {return new BufferedImageLuminanceSource(image, this.left + left, this.top + top, width, height);}@Overridepublic boolean isRotateSupported() {return true;}@Overridepublic 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);}}3.生成二维码图片的实现方法
/*** 根据内容，生成指定宽高、指定格式的二维码图片** @param text 内容* @param width 宽* @param height 高* @param format 图片格式* @return 生成的二维码图片路径* @throws Exception*/private static String generateQRCode(String text, int width, int height, String format) throws Exception {Hashtable hints = new Hashtable<>();hints.put(EncodeHintType.CHARACTER_SET, "utf-8");BitMatrix bitMatrix = new MultiFormatWriter().encode(text, BarcodeFormat.QR_CODE, width, height, hints);String pathName = "F:/new.png";File outputFile = new File(pathName);MatrixToImageWriter.writeToFile(bitMatrix, format, outputFile);return pathName;} 4.赠送一个有用的小方法---->随机生成指定长度的数字字母组合的验证码：
/*** 随机生成指定长度的验证码** @param length 验证码长度* @return 生成的验证码*/private static String generateNumCode(int length) {String val = "";String charStr = "char";String numStr = "num";Random random = new Random();//参数length，表示生成几位随机数for (int i = 0; i < length; i++) {String charOrNum = random.nextInt(2) % 2 == 0 ? charStr : numStr;//输出字母还是数字if (charStr.equalsIgnoreCase(charOrNum)) {//输出是大写字母还是小写字母int temp = random.nextInt(2) % 2 == 0 ? 65 : 97;val += (char) (random.nextInt(26) + temp);} else if (numStr.equalsIgnoreCase(charOrNum)) {val += String.valueOf(random.nextInt(10));}}return val;}5.解析指定路径下的二维码图片的实现方法：
/*** 解析指定路径下的二维码图片** @param filePath 二维码图片路径* @return*/private static String parseQRCode(String filePath) {String content = "";try {File file = new File(filePath);BufferedImage image = ImageIO.read(file);LuminanceSource source = new BufferedImageLuminanceSource(image);Binarizer binarizer = new HybridBinarizer(source);BinaryBitmap binaryBitmap = new BinaryBitmap(binarizer);Map hints = new HashMap<>();hints.put(DecodeHintType.CHARACTER_SET, "UTF-8");MultiFormatReader formatReader = new MultiFormatReader();Result result = formatReader.decode(binaryBitmap, hints);System.out.println("result 为：" + result.toString());System.out.println("resultFormat 为：" + result.getBarcodeFormat());System.out.println("resultText 为：" + result.getText());//设置返回值content = result.getText();} catch (Exception e) {e.printStackTrace();}return content;} 6.二维码生成、解析的测试类：
import com.google.zxing.*;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.common.HybridBinarizer;import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.Map;
import java.util.Random;/*** 利用Google的ZXing工具包，生成和解析二维码图片* * Created by Eric on 2017/2/15.*/
public class QRCodeEvents {public static void main(String[] args) {String text = generateNumCode(12); //随机生成的12位验证码System.out.println("随机生成的12位验证码为： " + text);int width = 100; //二维码图片的宽int height = 100; //二维码图片的高String format = "png"; //二维码图片的格式try {//生成二维码图片，并返回图片路径String pathName = generateQRCode(text, width, height, format);System.out.println("生成二维码的图片路径： " + pathName);String content = parseQRCode(pathName);System.out.println("解析出二维码的图片的内容为： " + content);} catch (Exception e) {e.printStackTrace();}}
}
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