QQ扫码登录实现与原理

二维码

扫码原理

实现代码

工具类

1

 	import com.google.zxing.LuminanceSource;
    
    import java.awt.*;
    import java.awt.geom.AffineTransform;
    import java.awt.image.BufferedImage;
    
    public 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;
    }

    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;
    }

    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;
    }

    public boolean isCropSupported() {
        return true;
    }

    public LuminanceSource crop(int left, int top, int width, int height) {
        return new BufferedImageLuminanceSource(image, this.left + left, this.top + top, width, height);
    }

    public boolean isRotateSupported() {
        return true;
    }

    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);
    }
	}

2

  	import com.google.zxing.*;
    import com.google.zxing.common.BitMatrix;
    import com.google.zxing.common.HybridBinarizer;
    import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
    
    import javax.imageio.ImageIO;
    import java.awt.*;
    import java.awt.geom.RoundRectangle2D;
    import java.awt.image.BufferedImage;
    import java.io.File;
    import java.io.OutputStream;
    import java.util.Hashtable;
    
    public class QRCodeUtil {
        private static final String CHARSET = "utf-8";
        private static final String FORMAT_NAME = "JPG";
        // 二维码尺寸
        private static final int QRCODE_SIZE = 300;
        // LOGO宽度
        private static final int WIDTH = 60;
        // LOGO高度
        private static final int HEIGHT = 60;

    public static BufferedImage createImage(String content, String imgPath, boolean needCompress) 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 width = bitMatrix.getWidth();
        int height = bitMatrix.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, bitMatrix.get(x, y) ? 0xFF000000 : 0xFFFFFFFF);
            }
        }
        if (imgPath == null || "".equals(imgPath)) {
            return image;
        }
        // 插入图片
        QRCodeUtil.insertImage(image, imgPath, needCompress);
        return image;
    }

    private static void insertImage(BufferedImage source, String imgPath, boolean needCompress) throws Exception {
        File file = new File(imgPath);
        if (!file.exists()) {
            System.err.println("" + imgPath + "   该文件不存在！");
            return;
        }
        Image src = ImageIO.read(new File(imgPath));
        int width = src.getWidth(null);
        int height = src.getHeight(null);
        if (needCompress) { // 压缩LOGO
            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();
            g.drawImage(image, 0, 0, null); // 绘制缩小后的图
            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();
    }

    public static void encode(String content, String imgPath, String destPath, boolean needCompress) throws Exception {
        BufferedImage image = QRCodeUtil.createImage(content, imgPath, needCompress);
        mkdirs(destPath);
        // String file = new Random().nextInt(99999999)+".jpg";
        // ImageIO.write(image, FORMAT_NAME, new File(destPath+"/"+file));
        ImageIO.write(image, FORMAT_NAME, new File(destPath));
    }

    public  BufferedImage encode(String content, String imgPath, boolean needCompress) throws Exception {
        BufferedImage image = QRCodeUtil.createImage(content, imgPath, needCompress);
        return image;
    }

    public static void mkdirs(String destPath) {
        File file = new File(destPath);
        // 当文件夹不存在时，mkdirs会自动创建多层目录，区别于mkdir．(mkdir如果父目录不存在则会抛出异常)
        if (!file.exists() && !file.isDirectory()) {
            file.mkdirs();
        }
    }

    public static void encode(String content, String imgPath, String destPath) throws Exception {
        QRCodeUtil.encode(content, imgPath, destPath, false);
    }
    // 被注释的方法
    /*
     * public static void encode(String content, String destPath, boolean
     * needCompress) throws Exception { QRCodeUtil.encode(content, null, destPath,
     * needCompress); }
     */

    public static void encode(String content, String destPath) throws Exception {
        QRCodeUtil.encode(content, null, destPath, false);
    }

    public static void encode(String content, String imgPath, OutputStream output, boolean needCompress)
            throws Exception {
        BufferedImage image = QRCodeUtil.createImage(content, imgPath, needCompress);
        ImageIO.write(image, FORMAT_NAME, output);
    }

    public static void encode(String content, OutputStream output) throws Exception {
        QRCodeUtil.encode(content, null, output, false);
    }

    public static String decode(File file) throws Exception {
        BufferedImage image;
        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);
        String resultStr = result.getText();
        return resultStr;
    }

    public static String decode(String path) throws Exception {
        return QRCodeUtil.decode(new File(path));
    }

	}

3

	@Component
	public class RedisUtils {

	@Autowired
	private StringRedisTemplate stringRedisTemplate;

	public void set(String key, Object object, Long time) {
		// 让该方法能够支持多种数据类型存放
		if (object instanceof String) {
			setString(key, object);
		}
		// 如果存放时Set类型
		if (object instanceof Set) {
			setSet(key, object);
		}
		// 设置有效期
		if (time != null) {
			stringRedisTemplate.expire(key, time, TimeUnit.SECONDS);
		}

	}

	public void setString(String key, Object object) {
		String value = (String) object;
		// 存放string类型
		stringRedisTemplate.opsForValue().set(key, value);
	}

	public void setSet(String key, Object object) {
		Set valueSet = (Set) object;
		for (String string : valueSet) {
			stringRedisTemplate.opsForSet().add(key, string);
		}
	}

	public String getString(String key) {
		return stringRedisTemplate.opsForValue().get(key);
	}

	public boolean delete(String key) {
		return stringRedisTemplate.delete(key);
	}

	}

pom 多加如下依赖

    
        com.google.zxing
        core
        3.3.0
    
    
    
        org.springframework.boot
        spring-boot-starter-data-redis
    
    
    
        org.springframework.boot
        spring-boot-starter-freemarker
    

yml

server:
  servlet:
    context-path: /
  port: 8088
spring:
  application:
    name: utils
  redis:
    database: 0
    host: 127.0.0.1
    port: 6379
    password: root
  freemarker:
      allow-request-override: false
      cache: false
      check-template-location: true
      charset: UTF-8
      content-type: text/html; charset=utf-8
      expose-request-attributes: false
      expose-session-attributes: false
      expose-spring-macro-helpers: false
      suffix: .ftl
      template-loader-path: classpath:/templates
#token更新地址，此地址需要外网地址才行，使用natapp穿透下 https://blog.csdn.net/qq_40673786/article/details/90298955
baseImgUrl: http://xdc5z3.natappfree.cc/updateTokenState?token=
#二维码log图片地址
bgImgPath: F:/a.jpg

QRCodeController

@Controller
public class QRCodeController {
    @Autowired
    private RedisUtils redisUtils;
    @Value("${baseImgUrl}")
    private String baseImgUrl;
    @Value("${bgImgPath}")
    private String bgImgPath;
	//生成token地址
    @RequestMapping(value = "/generateCode")
    @ResponseBody
    public String generateCode() throws Exception {
        // 1.生成token令牌
        String token = UUID.randomUUID().toString().replace("-", "");
        // 2.存入到redis中
        redisUtils.setString(token, "0");
        // 3.生成图形验证码 在验证码中传递该参数
        String codeText = baseImgUrl + token;
        String destPath = "F:/code/" + token + ".png";
        // 4.将二维码写入到本地文件中
        QRCodeUtil.encode(codeText, bgImgPath, destPath, true);
        return token;
    }
	//获取生成的二维码图片
    @RequestMapping(value = "/getCodeImg", produces = MediaType.IMAGE_JPEG_VALUE)
    @ResponseBody
    public byte[] getCodeImg(String token) throws IOException {
        File file = new File("F:/code/" + token + ".png");
        FileInputStream inputStream = new FileInputStream(file);
        byte[] bytes = new byte[inputStream.available()];
        inputStream.read(bytes, 0, inputStream.available());
        return bytes;
    }
	//跳到扫码页
    @RequestMapping("/")
    public String index(String token, HttpServletRequest request) {
        request.setAttribute("token", token);
        return "index";
    }
	//扫描二维码时调用此接口，二维码内容即此接口地址
    @RequestMapping("/updateTokenState")
    @ResponseBody
    public String updateTokenState(String token) {
        if (StringUtils.isEmpty(token)) {
            return "扫码登陆失败!";
        }
        // 将token状态改为1
        redisUtils.setString(token, "1");
        return "扫码登陆成功!";
    }
	//前端检测redistoken是否被更改，即是否已经扫过码了
    @RequestMapping("/checkToken")
    @ResponseBody
    public boolean checkToken(String token) {
        if (StringUtils.isEmpty(token)) {
            return false;
        }
        String redisValue = redisUtils.getString(token);
        if (StringUtils.isEmpty(redisValue)) {
            return false;
        }
        if (!redisValue.equals("1")) {
            return false;
        }
        return true;
    }
	//扫过码之后要跳转的地址
    @ResponseBody
    @RequestMapping("/sweepCode")
    public String sweepCode() {
        return "扫码登录成功！";
    }
}

App

@SpringBootApplication
public class App {
    public static void main(String[] args) {
        SpringApplication.run(App.class, args);
    }
}

index.ftl 此ftl在resources/templates文件夹下

扫一下该二维码，实现扫码登陆

测试 前提 1、启动redis 2、生成外网地址
第一步
http://localhost:8088/generateCode 生成token
第二步
http://localhost:8088/?token=上述生成的token

查看生成到本地F://code/下的的二维码
http://localhost:8088/getCodeImg?token=上述生成的token

思想来源
www.mayikt.com/