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【工作技能】二维码生成

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关于二维码的生成与使用

1 com.google.zxing依赖

1.1 依赖

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<!-- https://mvnrepository.com/artifact/com.google.zxing/core -->
<dependency>
	<groupId>com.google.zxing</groupId>
	<artifactId>core</artifactId>
	<version>3.4.1</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.google.zxing/javase -->
<dependency>
	<groupId>com.google.zxing</groupId>
	<artifactId>javase</artifactId>
	<version>3.4.1</version>
</dependency>

1.2 创建工具类

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/**
 * 二维码工具类
 * @author letere
 * @create 2021-05-18 11:30
 */
public class QRCodeUtil {

    private final static String CODE = "utf-8"; //编码格式
    private final static int WIDTH = 300; //二维码宽
    private final static int HEIGHT = 300; //二维码高
    private final static String FORMAT = "png"; //二维码图片格式


    /**
     * 生成二维码
     * @param outputStream 输出流
     * @param data 数据
     * @param <T> 泛型
     * @throws Exception
     */
    public static<T> void create(OutputStream outputStream, T data) throws Exception{
        //获取二维码生成参数
        Map<EncodeHintType, Object> hints = getEncodeHints();

        //将类转成String类型
        String content = String.valueOf(data);

        //生成二维码信息（编码）
        MultiFormatWriter multiFormatWriter = new MultiFormatWriter();
        BitMatrix encode = multiFormatWriter.encode(content, BarcodeFormat.QR_CODE, WIDTH, HEIGHT, hints);

        //输出二维码
        MatrixToImageWriter.writeToStream(encode, FORMAT,  outputStream);
    }

    
    /**
     * 获取二维码编码参数
     * @return Map<EncodeHintType, Object>
     */
    private static Map<EncodeHintType, Object> getEncodeHints() {
        Map<EncodeHintType, Object> hints = new HashMap<>();
        hints.put(EncodeHintType.CHARACTER_SET, CODE); //编码格式
        hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.M); //纠错等级
        hints.put(EncodeHintType.MARGIN, 1); //外边距（白边）

        return hints;
    }


    /**
     * 读取二维码
     * @param inputStream 输入流
     * @param c 返回数据类型
     * @param <T> 泛型
     * @return T
     * @throws Exception
     */
    public static<T> T read(InputStream inputStream, Class<T> c) throws Exception{
        //读取二维码图片
        BufferedImage image = ImageIO.read(inputStream);
        BinaryBitmap binaryBitmap = new BinaryBitmap(new HybridBinarizer(new BufferedImageLuminanceSource(image)));

        //读取二维码中的内容（解码）
        Map<DecodeHintType, Object> hints = getDecodeHints();
        MultiFormatReader formatReader = new MultiFormatReader();
        Result result = formatReader.decode(binaryBitmap, hints);

        //类型强转为指定指定数据类型
        return (T) result.getText();
    }
    
    
    /**
     * 获取二维码解码参数
     * @return Map<DecodeHintType, Object>
     */
    private static Map<DecodeHintType, Object> getDecodeHints() {
        Map<DecodeHintType, Object> hints = new HashMap<>();
        hints.put(DecodeHintType.CHARACTER_SET, CODE); //解码格式

        return hints;
    }
}

1.3 代码测试

  • （1）生成二维码测试
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    @Test
    public void fileTest() throws Exception{
    	String text = "https://www.bilibili.com";
    	File file = new File("./src/main/resources/qr.png");
    	FileOutputStream fos = new FileOutputStream(file);

    	//工具类生成二维码（输出流，二维码内容）
    	QRCodeUtil.create(fos, text);
    }
  • （2）读取二维码测试
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    @Test
    public void fileTest() throws Exception{
    	File file = new File("./src/main/resources/qr.png");
    	FileInputStream fis = new FileInputStream(file);

    	//工具类读取二维码图片内容（图片输入流，读取后的数据类型）
    	String data = QRCodeUtil.read(fis, String.class);
    	System.out.println(data);
    }