Java 二维码生成与解析
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· 阅读数 45
前言
二维码是一种能够将大量信息编码在小空间的编码器。它是一种由黑白方块构成的图片，可以将文本、链接、图像等不同类型的信息编码到其中。二维码已经广泛应用于不同的领域，如电子支付、电子门票、商品销售等，这种快捷、高效的信息处理方式已成为现代生活中不可或缺的一部分。
所需依赖
<!-- 二维码生成 -->
<dependency>
<groupId>com.google.zxing</groupId>
<artifactId>core</artifactId>
<version>3.5.1</version>
</dependency>
<dependency>
<groupId>com.google.zxing</groupId>
<artifactId>javase</artifactId>
<version>3.5.1</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework/spring-mock -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-mock</artifactId>
<version>2.0.8</version>
<scope>compile</scope>
</dependency>
主要代码
需要用到的一些常量
/** 字符编码 */
private static final String CHARSET = "utf-8";
/** 图片格式 */
private static final String FORMAT_NAME = "JPG";
/** 二维码尺寸 */
private static final Integer QRCODE_SIZE = 380;
/** LOGO宽度 */
private static final Integer WIDTH = 100;
/** LOGO高度 */
private static final Integer HEIGHT = 100;
生成二维码
/**
* 生成二维码，得到 MultipartFile--通用
* @param jsonString 二维码内容
* @param logoPath logo路径
* @param bottomText 底部文字
* @return {@link MultipartFile}
* @ver v1.0.0
*/
public static MultipartFile createQrCode(String jsonString, String logoPath, String bottomText) throws Exception {
return initMultipartFile(jsonString, logoPath, bottomText);
}
/**
* 生成二维码，得到 MultipartFile-有logo、无底部文字
* @param jsonString 二维码内容
* @param logoPath logo路径
* @return {@link MultipartFile}
* @ver v1.0.0
*/
public static MultipartFile createQrCode(String jsonString, String logoPath) throws Exception {
return initMultipartFile(jsonString, logoPath, null);
}
/**
* 生成二维码，得到 MultipartFile-无logo、无底部文字
* @param jsonString 二维码内容
* @return {@link MultipartFile}
* @ver v1.0.0
*/
public static MultipartFile createQrCode(String jsonString) throws Exception {
return initMultipartFile(jsonString, null, null);
}
/**
* 生成二维码
* @param content 二维码内容
* @param logoPath logo路径
* @param bottomText 底部文字
* @return {@link MultipartFile}
* @ver v1.0.0
*/
private static MultipartFile initMultipartFile(String content, String logoPath, String bottomText) throws Exception {
//二维码名称
String qrName = "qr" + System.currentTimeMillis() + ".jpg";
int height = 0;
if (StringUtils.hasText(bottomText)) {
height = 10;
}
//得到BufferedImage对象
BufferedImage bufferedImage = createImage(content, logoPath, true, height);
// 判断是否添加底部文字
if (StringUtils.hasText(bottomText)) {
addBottomText(bufferedImage, bottomText);
}
//创建一个ByteArrayOutputStream
ByteArrayOutputStream os = new ByteArrayOutputStream();
//把BufferedImage写入ByteArrayOutputStream
ImageIO.write(bufferedImage, "jpg", os);
//ByteArrayOutputStream转成InputStream
InputStream input = new ByteArrayInputStream(os.toByteArray());
//InputStream转成MultipartFile
return new MockMultipartFile("qrFile", qrName, "text/plain", input);
}
/**
* 生成 BufferedImage
* @param content 存放在二维码中的内容
* @param imgPath logo的路径及名称
* @param needCompress 是否需要压缩
* @param height 额外高度（有底部文字时）
* @return {@link BufferedImage}
* @ver v1.0.0
*/
private static BufferedImage createImage(String content, String imgPath, boolean needCompress, int height) throws Exception {
Hashtable hints = new Hashtable();
hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
hints.put(EncodeHintType.CHARACTER_SET, CHARSET);
hints.put(EncodeHintType.MARGIN, 1);
BitMatrix bitMatrix = new MultiFormatWriter()
.encode(content, BarcodeFormat.QR_CODE, QRCODE_SIZE, QRCODE_SIZE, hints);
int bitWidth = bitMatrix.getWidth();
int bitHeight = bitMatrix.getHeight();
BufferedImage image = new BufferedImage(bitWidth, bitHeight + height, BufferedImage.TYPE_INT_RGB);
for (int x = 0; x < bitWidth; x++) {
for (int y = 0; y < bitHeight; y++) {
image.setRGB(x, y, bitMatrix.get(x, y) ? 0xFF000000 : 0xFFFFFFFF);
}
}
if (imgPath == null || "".equals(imgPath)) {
return image;
}
// 插入logo图片
insertImage(image, imgPath, needCompress);
return image;
}
/**
* 插入logo图片
* @param source 二维码
* @param logoPath logo的路径及名称
* @param needCompress 是否需要压缩
* @ver v1.0.0
*/
private static void insertImage(BufferedImage source, String logoPath, boolean needCompress) throws Exception {
File file = new File(logoPath);
if (!file.exists()) {
log.error(logoPath + " 该文件不存在！");
return;
}
Image src = ImageIO.read(new File(logoPath));
int width = src.getWidth(null);
int height = src.getHeight(null);
// 压缩LOGO
if (needCompress) {
if (width > WIDTH) {
width = WIDTH;
}
if (height > HEIGHT) {
height = HEIGHT;
}
Image image = src.getScaledInstance(width, height, Image.SCALE_SMOOTH);
BufferedImage tag = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics g = tag.getGraphics();
// 绘制缩小后的图
g.drawImage(image, 0, 0, null);
g.dispose();
src = image;
}
// 插入LOGO
Graphics2D graph = source.createGraphics();
int x = (QRCODE_SIZE - width) / 2;
int y = (QRCODE_SIZE - height) / 2;
graph.drawImage(src, x, y, width, height, null);
Shape shape = new RoundRectangle2D.Float(x, y, width, width, 6, 6);
graph.setStroke(new BasicStroke(3f));
graph.draw(shape);
graph.dispose();
}
/**
* 二维码底部添加文字
* @param source 二维码
* @param bottomText 底部文字
* @ver v1.0.0
*/
private static void addBottomText(BufferedImage source, String bottomText) {
//生成image
int defineWidth = QRCODE_SIZE;
int defineHeight = 20;
BufferedImage textImage = new BufferedImage(defineWidth, defineHeight, BufferedImage.TYPE_INT_RGB);
Graphics2D g2 = (Graphics2D) textImage.getGraphics();
//开启文字抗锯齿
g2.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
g2.setBackground(Color.WHITE);
g2.clearRect(0, 0, defineWidth, defineHeight);
g2.setPaint(Color.BLACK);
FontRenderContext context = g2.getFontRenderContext();
//部署linux需要注意 linux无此字体会显示方块
Font font = new Font("微软雅黑", Font.BOLD, 15);
g2.setFont(font);
LineMetrics lineMetrics = font.getLineMetrics(bottomText, context);
FontRenderContext frc = new FontRenderContext(new AffineTransform(), true, true);
Rectangle rec = font.getStringBounds(bottomText, frc).getBounds();
double fontWidth = rec.getWidth();
double offset = (defineWidth - fontWidth) / 2;
float y = (defineHeight + lineMetrics.getAscent() - lineMetrics.getDescent() - lineMetrics.getLeading()) / 2;
g2.drawString(bottomText, (int) offset, (int) y);
Graphics2D graph = source.createGraphics();
//开启文字抗锯齿
graph.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
//添加image
int width = textImage.getWidth(null);
int height = textImage.getHeight(null);
graph.drawImage(textImage, 0, QRCODE_SIZE - 8, width, height, Color.WHITE, null);
graph.dispose();
}
二维码解析
/**
* 根据二维码路径解析二维码
* @param path 二维码路径
* @return {@link String}
* @ver v1.0.0
*/
public static String decode(String path) throws Exception {
return decode(new File(path));
}
/**
* 根据二维码文件解析二维码
* @param file 二维码文件
* @return {@link String}
* @ver v1.0.0
*/
public static String decode(File file) throws Exception {
BufferedImage image = ImageIO.read(file);
if (image == null) {
return null;
}
BufferedImageLuminanceSource source = new BufferedImageLuminanceSource(image);
BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
Result result;
Hashtable hints = new Hashtable();
hints.put(DecodeHintType.CHARACTER_SET, CHARSET);
result = new MultiFormatReader().decode(bitmap, hints);
return result.getText();
}
是不是很简单0.0 好了，到这就结束啦！！！
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转载自:https://juejin.cn/post/7244810003592151098