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:
<!-- https://mvnrepository.com/artifact/com.google.zxing/core --> <dependency> <groupId>com.google.zxing</groupId> <artifactId>core</artifactId> <version>3.3.0</version> </dependency>
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; } @Override 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; } @Override 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; } @Override public boolean isCropSupported() { return true; } @Override public LuminanceSource crop(int left, int top, int width, int height) { return new BufferedImageLuminanceSource(image, this.left + left, this.top + top, width, height); } @Override public boolean isRotateSupported() { return true; } @Override 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); } }
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<EncodeHintType, Object> 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<DecodeHintType, Object> 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 * <p> * 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(); } } }
说明:以上类中未写package语句,需自行补上。
形而上者谓之道,形而下者谓之器