Java生成、解析二维码

内容简介：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>

</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。

• 原文：https://www.cnblogs.com/xz-luckydog/p/6402568.html

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