1、在项目中会遇到扫描二维码去采集信息或者查看数据信息，所以下面介绍生成二维码的简单使用！
需要引入生成二维码的jar包
<dependency>
<groupId>com.google.zxing</groupId>
<artifactId>core</artifactId>
<version>3.3.0</version>
</dependency>
2、下面介绍生成二维码的代码
/** * 生成二维码 * @param qrCodeUrl 生成二维码的URL -- 比较关键的信息需要使用BASE64加密或者使用其他的加密方式都可以 * @param fileName 生成二维码的文件名称 * @return */ public InputStream createQRCode(String qrCodeUrl, String fileName) { logger.info("下载二维码，生成二维码URL：{}", qrCodeUrl); String qrCodeName = "/qrcode/" + fileName; File file = new File(qrCodeName); if (!file.getParentFile().exists()) { file.getParentFile().mkdirs(); } // 二维码图片的宽 final int width = 300; // 二维码图片的高 final int height = 300; // 二维码图片的格式 String format = "png"; try { // 生成二维码图片，并返回图片路径 String pathName = QRCodeUtils.generateQRCode(qrCodeUrl, width, height, format, qrCodeName); logger.info("生成二维码的图片路径：{}", pathName); return new FileInputStream(new File(pathName)); } catch (Exception e) { logger.error("下载二维码失败：{}", e); } finally { try { if (file != null && file.exists()) { file.delete(); logger.info("删除二维码的图片成功"); } } catch (Exception e) { logger.error("二维码的图片删除失败：{}", e); } } return null; }
3、生成二维码的工具类的实现（QRCodeUtils）
package com.htc.iop.utils;
import com.google.zxing.*;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.common.HybridBinarizer;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletResponse;
import java.awt.*;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.Map;
/**
* @Autor Liutao
* @Date 2021/10/8 16:09
*/
public class QRCodeUtils extends LuminanceSource {
private static final Logger logger = LoggerFactory.getLogger(QRCodeUtils.class);
// 二维码颜色
private static final int BLACK = 0xFF000000;
// 二维码颜色
private static final int WHITE = 0xFFFFFFFF;
private final BufferedImage image;
private final int left;
private final int top;
public QRCodeUtils(BufferedImage image) {
this(image, 0, 0, image.getWidth(), image.getHeight());
}
public QRCodeUtils(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;
}
/**
* @param matrix
* @return
*/
private 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;
}
/**
* 生成二维码图片
*
* @param matrix
* @param format
* @param file
* @throws IOException
*/
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);
}
}
/**
* 生成二维码图片流
*
* @param matrix
* @param format
* @param stream
* @throws IOException
*/
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);
}
}
/**
* 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
*/
public static String generateQRCode(String text, int width, int height, String format, String pathName)
throws Exception {
Hashtable<EncodeHintType, Object> hints = new Hashtable<EncodeHintType, Object>();
hints.put(EncodeHintType.CHARACTER_SET, "utf-8");// 指定编码格式
hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);// 指定纠错等级
hints.put(EncodeHintType.MARGIN, 1); // 白边大小，取值范围0~4
BitMatrix bitMatrix = new MultiFormatWriter().encode(text, BarcodeFormat.QR_CODE, width, height, hints);
File outputFile = new File(pathName);
writeToFile(bitMatrix, format, outputFile);
return pathName;
}
/**
* 输出二维码图片流
*
* @param text 二维码内容
* @param width 二维码宽
* @param height 二维码高
* @param format 图片格式eg: png, jpg, gif
* @param response HttpServletResponse
* @throws Exception
*/
public static void generateQRCode(String text, int width, int height, String format, HttpServletResponse response)
throws Exception {
Hashtable<EncodeHintType, Object> hints = new Hashtable<EncodeHintType, Object>();
hints.put(EncodeHintType.CHARACTER_SET, "utf-8");// 指定编码格式
hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);// 指定纠错等级
hints.put(EncodeHintType.MARGIN, 1); // 白边大小，取值范围0~4
BitMatrix bitMatrix = new MultiFormatWriter().encode(text, BarcodeFormat.QR_CODE, width, height, hints);
writeToStream(bitMatrix, format, response.getOutputStream());
}
/**
* 解析指定路径下的二维码图片
*
* @param filePath 二维码图片路径
* @return
*/
public static String parseQRCode(String filePath) {
String content = "";
try {
File file = new File(filePath);
BufferedImage image = ImageIO.read(file);
LuminanceSource source = new QRCodeUtils(image);
Binarizer binarizer = new HybridBinarizer(source);
BinaryBitmap binaryBitmap = new BinaryBitmap(binarizer);
Map<DecodeHintType, Object> hints = new HashMap<DecodeHintType, Object>();
hints.put(DecodeHintType.CHARACTER_SET, "UTF-8");
MultiFormatReader formatReader = new MultiFormatReader();
Result result = formatReader.decode(binaryBitmap, hints);
logger.info("result 为：" + result.toString());
logger.info("resultFormat 为：" + result.getBarcodeFormat());
logger.info("resultText 为：" + result.getText());
// 设置返回值
content = result.getText();
} catch (Exception e) {
logger.error(e.getMessage());
}
return content;
}
@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 QRCodeUtils(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 QRCodeUtils(rotatedImage, top, sourceWidth - (left + width), getHeight(), width);
}
}
希望可以帮到有需要的朋友！谢谢！