Java实现一个复杂的图形验证码

谁借莪１个温暖的怀抱￠ 2024-03-23 16:39 68阅读 0赞

这个验证码将包括以下特性：

> 1. 7个字符，包含英文大小写字母、数字和符号；
> 
> 2. 不同的字符将有不同的颜色；
> 
> 3. 字符随机旋转；
> 
> 4. 随机噪点（包括随机噪点颜色、数量和大小）；
> 
> 5. 随机干扰弧线（包括干扰弧线颜色、数量、宽度和角度）；
> 
> 6. 随机干扰直线（包括干扰直线颜色、数量、宽度和长度）；
> 
> 7. 随机背景色；
> 
> 8. 随机字体（包括字体、大小和样式）。

下面是这个验证码的示例代码：

import java.awt.BasicStroke;
    import java.awt.Color;
    import java.awt.Font;
    import java.awt.Graphics2D;
    import java.awt.RenderingHints;
    import java.awt.geom.AffineTransform;
    import java.awt.geom.QuadCurve2D;
    import java.awt.image.BufferedImage;
    import java.io.OutputStream;
    import java.util.Random;
    import javax.imageio.ImageIO;
     public class ComplexCaptchaUtil {
        private static final int IMAGE_WIDTH = 200; // 验证码图片宽度
        private static final int IMAGE_HEIGHT = 80; // 验证码图片高度
        private static final int CHAR_COUNT = 7; // 字符个数
        private static final String CHAR_SET = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!@#$%^&*()_+[];:/?<>,.'{}\"\\|~`"; // 字符集
        private static final int CHAR_SPACING = 20; // 字符间距
        private static final int ROTATION_RANGE = 45; // 字符随机旋转角度范围
        private static final int NOISE_POINT_COUNT = 200; // 随机噪点数量
        private static final int NOISE_POINT_RADIUS_MIN = 1; // 随机噪点半径最小值
        private static final int NOISE_POINT_RADIUS_MAX = 3; // 随机噪点半径最大值
        private static final int NOISE_ARC_COUNT = 6; // 随机弧线数量
        private static final int NOISE_ARC_WIDTH_MIN = 5; // 随机弧线宽度最小值
        private static final int NOISE_ARC_WIDTH_MAX = 10; // 随机弧线宽度最大值
        private static final int NOISE_ARC_ANGLE_MIN = -30; // 随机弧线角度最小值
        private static final int NOISE_ARC_ANGLE_MAX = 30; // 随机弧线角度最大值
        private static final int NOISE_LINE_COUNT = 20; // 随机直线数量
        private static final int NOISE_LINE_WIDTH_MIN = 1; // 随机直线宽度最小值
        private static final int NOISE_LINE_WIDTH_MAX = 3; // 随机直线宽度最大值
        private static final int NOISE_LINE_LENGTH_MIN = 10; // 随机直线长度最小值
        private static final int NOISE_LINE_LENGTH_MAX = 30; // 随机直线长度最大值
        private static final String[] FONT_NAMES = { "Arial", "Courier New", "Georgia", "Times New Roman", "Verdana" }; // 字体名称
        private static final int FONT_SIZE_MIN = 36; // 字体大小最小值
        private static final int FONT_SIZE_MAX = 48; // 字体大小最大值
        private static final int FONT_STYLE_NORMAL = Font.PLAIN; // 字体样式-正常
        private static final int FONT_STYLE_BOLD = Font.BOLD; // 字体样式-加粗
        private static final int FONT_STYLE_ITALIC = Font.ITALIC; // 字体样式-斜体
        private static final int FONT_STYLE_BOLD_ITALIC = Font.BOLD | Font.ITALIC; // 字体样式-加粗斜体
        private static final int BACKGROUND_COLOR_RANGE = 100; // 背景色范围
         public static void generate(OutputStream os) throws Exception {
            // 创建验证码图片
            BufferedImage image = new BufferedImage(IMAGE_WIDTH, IMAGE_HEIGHT, BufferedImage.TYPE_INT_RGB);
             // 获取绘制对象
            Graphics2D g = image.createGraphics();
            g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
            g.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
             // 生成随机背景色
            Random random = new Random();
            int r = random.nextInt(BACKGROUND_COLOR_RANGE);
            int gVal = random.nextInt(BACKGROUND_COLOR_RANGE);
            int b = random.nextInt(BACKGROUND_COLOR_RANGE);
            g.setColor(new Color(r, gVal, b));
            g.fillRect(0, 0, IMAGE_WIDTH, IMAGE_HEIGHT);
             // 设置字体
            Font font = new Font(FONT_NAMES[random.nextInt(FONT_NAMES.length)],
                    getRandomFontStyle(), getRandomFontSize());
            g.setFont(font);
             // 随机生成字符、颜色、位置和旋转角度
            char[] captcha = new char[CHAR_COUNT];
            Color[] colors = new Color[CHAR_COUNT];
            int[] xPos = new int[CHAR_COUNT];
            int[] yPos = new int[CHAR_COUNT];
            double[] rotations = new double[CHAR_COUNT];
            for (int i = 0; i < CHAR_COUNT; i++) {
                captcha[i] = CHAR_SET.charAt(random.nextInt(CHAR_SET.length()));
                colors[i] = new Color(random.nextInt(256), random.nextInt(256), random.nextInt(256));
                xPos[i] = CHAR_SPACING * i + 10;
                yPos[i] = IMAGE_HEIGHT / 2 + font.getSize() / 2 - random.nextInt(10);
                rotations[i] = Math.toRadians(random.nextInt(ROTATION_RANGE) - ROTATION_RANGE / 2);
            }
             // 绘制字符
            for (int i = 0; i < CHAR_COUNT; i++) {
                g.setColor(colors[i]);
                AffineTransform transform = new AffineTransform();
                transform.rotate(rotations[i], xPos[i], yPos[i]);
                g.setTransform(transform);
                g.drawString(String.valueOf(captcha[i]), xPos[i], yPos[i]);
            }
             // 随机生成噪点
            for (int i = 0; i < NOISE_POINT_COUNT; i++) {
                int x = random.nextInt(IMAGE_WIDTH);
                int y = random.nextInt(IMAGE_HEIGHT);
                int radius = random.nextInt(NOISE_POINT_RADIUS_MAX - NOISE_POINT_RADIUS_MIN + 1)
                        + NOISE_POINT_RADIUS_MIN;
                Color color = new Color(random.nextInt(256), random.nextInt(256), random.nextInt(256));
                g.setColor(color);
                g.fillOval(x, y, radius, radius);
            }
             // 随机生成干扰弧线
            for (int i = 0; i < NOISE_ARC_COUNT; i++) {
                int x1 = random.nextInt(IMAGE_WIDTH);
                int y1 = random.nextInt(IMAGE_HEIGHT);
                int x2 = random.nextInt(IMAGE_WIDTH);
                int y2 = random.nextInt(IMAGE_HEIGHT);
                int width = random.nextInt(NOISE_ARC_WIDTH_MAX - NOISE_ARC_WIDTH_MIN + 1) + NOISE_ARC_WIDTH_MIN;
                int angle1 = random.nextInt(NOISE_ARC_ANGLE_MAX - NOISE_ARC_ANGLE_MIN + 1) + NOISE_ARC_ANGLE_MIN;
                int angle2 = random.nextInt(NOISE_ARC_ANGLE_MAX - NOISE_ARC_ANGLE_MIN + 1) + NOISE_ARC_ANGLE_MIN;
                Color color = new Color(random.nextInt(256), random.nextInt(256), random.nextInt(256));
                g.setColor(color);
                g.setStroke(new BasicStroke(width));
                g.draw(new QuadCurve2D.Float(x1, y1, IMAGE_WIDTH / 2, IMAGE_HEIGHT / 2 + 20, x2, y2));
                g.setStroke(new BasicStroke(1));
            }
             // 随机生成干扰直线
            for (int i = 0; i < NOISE_LINE_COUNT; i++) {
                int x1 = random.nextInt(IMAGE_WIDTH);
                int y1 = random.nextInt(IMAGE_HEIGHT);
                int x2 = x1
                        + (int) ((random.nextInt(NOISE_LINE_LENGTH_MAX - NOISE_LINE_LENGTH_MIN + 1)
                                + NOISE_LINE_LENGTH_MIN)
                                * Math.cos(Math.toRadians(random.nextInt(360))));
                int y2 = y1
                        + (int) ((random.nextInt(NOISE_LINE_LENGTH_MAX - NOISE_LINE_LENGTH_MIN + 1)
                                + NOISE_LINE_LENGTH_MIN)
                                * Math.sin(Math.toRadians(random.nextInt(360))));
                int width = random.nextInt(NOISE_LINE_WIDTH_MAX - NOISE_LINE_WIDTH_MIN + 1) + NOISE_LINE_WIDTH_MIN;
                Color color = new Color(random.nextInt(256), random.nextInt(256), random.nextInt(256));
                g.setColor(color);
                g.setStroke(new BasicStroke(width));
                g.drawLine(x1, y1, x2, y2);
                g.setStroke(new BasicStroke(1));
            }
             // 将验证码图片输出到流中
            ImageIO.write(image, "JPEG", os);
        }
         private static int getRandomFontSize() {
            return new Random().nextInt(FONT_SIZE_MAX - FONT_SIZE_MIN + 1) + FONT_SIZE_MIN;
        }
         private static int getRandomFontStyle() {
            int[] styles = { FONT_STYLE_NORMAL, FONT_STYLE_BOLD, FONT_STYLE_ITALIC, FONT_STYLE_BOLD_ITALIC };
            return styles[new Random().nextInt(styles.length)];
        }
    }

> 这个示例代码生成一个包含7个数字与字母字符的验证码图片，使用了随机颜色的干扰线来增加验证码的难度。可以调整常量值以自定义验证码的属性。
> 
> 可以通过调用CaptchaUtil.generate(os)方法传入输出流来得到一个新的验证码图片。

@RequestMapping("/test1")
        public void test1(HttpServletResponse response) throws IOException {
    
            ServletOutputStream responseOutputStream = response.getOutputStream();
            try {
                ComplexCaptchaUtil.generate(responseOutputStream);
            } catch (Exception e) {
                throw new RuntimeException(e);
            }
            responseOutputStream.flush();
            responseOutputStream.close();
        }