Java生成、解析二维码
今天遇到需求，使用Java生成二维码图片，现在来总结一下。
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>
</dependency2. 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。
- 原文：https://www.cnblogs.com/xz-luckydog/p/6402568.html
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原始发表：2018-01-26，如有侵权请联系 cloudcommunity@tencent.com 删除
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