java验证码开发示例、java生成二维码示例

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 验证码是一种区分用户是计算机还是人的公共全自动程序；可以防止恶意破解密码、刷票、论坛灌水、刷页、恶意注册、登录。

直接上代码

public static void main(String[] args) throws IOException {
        Random rand = new Random();
        //画板
        BufferedImage i = new BufferedImage(200, 100, 1);
        //画笔
        var m = i.createGraphics();
        //平滑度
        m.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_GASP);
        m.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        m.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL, RenderingHints.VALUE_STROKE_DEFAULT);
        m.setColor(new Color(rand.nextInt(255), rand.nextInt(255), rand.nextInt(255), rand.nextInt(150, 200)));
        m.fillRect(0, 0, 200, 100);
        Font font = new Font("宋体", Font.BOLD, 50);
        m.setFont(font);
        var fm = m.getFontMetrics(font);
        //验证字符
        String setter = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
        StringBuilder sb = new StringBuilder();
        //生成随机验证码
        for (int j = 0; j < 6; j++) {
            //随机颜色
            m.setColor(new Color(rand.nextInt(120, 255), rand.nextInt(120, 255), rand.nextInt(120, 255), 255));
            int x = j * 30 + 10;
            //验证字符位置
            int y1 = i.getHeight() / 2 + (fm.getAscent() - fm.getDescent()) / 2 - fm.getHeight() / 3;
            int y2 = i.getHeight() / 2 + (fm.getAscent() - fm.getDescent()) / 2 + fm.getHeight() / 3;
            int a = rand.nextInt(setter.length());
            font.deriveFont(rand.nextInt(45, 55));
            var s = setter.substring(a, a + 1);
            m.drawString(s, x, rand.nextInt(y1, y2));
            sb.append(s);
        }

        //验证码干扰
        for (int j = 0; j < 10; j++) {
            m.setColor(new Color(rand.nextInt(255), rand.nextInt(255), rand.nextInt(255), rand.nextInt(50, 120)));
            int a = rand.nextInt(setter.length());
            var s = setter.substring(a, a + 1);
            m.drawString(s, rand.nextInt(10, 190), rand.nextInt(10, 90));
        }

        for (int j = 0; j < 3; j++) {
            m.setColor(new Color(rand.nextInt(255), rand.nextInt(255), rand.nextInt(255), rand.nextInt(100, 200)));
            m.setStroke(new BasicStroke(3));
            m.drawLine(rand.nextInt(10, 20), rand.nextInt(20, 90), rand.nextInt(170, 190), rand.nextInt(20, 90));

        }
        //曲线干扰
        Point[] points = {new Point(0, 0), new Point(0, rand.nextInt(100)), new Point(200, rand.nextInt(100))

        };

        GeneralPath path = new GeneralPath();
        path.moveTo(points[0].x, points[0].y);
        for (int i2 = 0; i2 < points.length - 1; ++i2) {
            Point sp = points[i2];
            Point ep = points[i2 + 1];
            Point c1 = new Point((sp.x + ep.x) / 2, sp.y);
            Point c2 = new Point((sp.x + ep.x) / 2, ep.y);
            path.curveTo(c1.x, c1.y, c2.x, c2.y, ep.x, ep.y);
        }

        // g.draw(path);
        for (int n = 0; n <= 355; n += 10) {
            // g.drawArc(100, 200, 600, 300, n, 5);
        }

        int yy = 100;// y
        int hh = 100;// 高度
        int aa = 200;//
        // x
        for (int x = 10; x < 200; x += 15) {
            int y = (int) (yy + hh * Math.sin(x * Math.PI / aa));
            //g.drawLine(x, (int) y, x, (int) y);
            m.fillOval(x, y, 6, 6);
        }

        m.dispose();
        ImageIO.write(i, "jpg", new File("yanzheng.jpg"));
        Runtime.getRuntime().exec("cmd /k start yanzheng.jpg");

    }

​

 QR Code码，是由Denso公司于1994年9月研制的一种矩阵二维码符号，它具有一维条码及其它二 维条码所具有的信息容量大、可靠性高、可表示汉字及图象多种文字信息、保密防伪性强等优点。 maven项目，pom.xml添加依赖 }

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

public static void main(String[] args) throws WriterException, IOException, ChecksumException, NotFoundException, FormatException {
        //Map存入编码格式
        Map<EncodeHintType, Object> hint = new HashMap<>();
        //设置二维码内容
        //var a = new BufferedReader(new FileReader("E:\maven\aa1.txt"));
        hint.put(EncodeHintType.CHARACTER_SET, "UTF-8");
        //使用组件设置内容大小格式
        var bm = new QRCodeWriter().encode("tt", BarcodeFormat.QR_CODE, 200, 200, hint);
        var i = MatrixToImageWriter.toBufferedImage(bm);
        ImageIO.write(i, "png", new FileOutputStream("qr.png"));
        //读取QRcode
        var img = ImageIO.read(new File("qr.png"));
        var src = new BufferedImageLuminanceSource(img);
        var binarizer = new HybridBinarizer(src);
        var binaryBitmap = new BinaryBitmap(binarizer);
        var result = new QRCodeReader().decode(binaryBitmap);
        System.out.println(result.getText());
    }

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