后端生成随机验证码

最新推荐文章于 2025-04-21 20:27:54 发布

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最新推荐文章于 2025-04-21 20:27:54 发布

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分类专栏： SpringBoot 文章标签： java spring boot

本文链接：https://blog.youkuaiyun.com/qq_53318060/article/details/125195346

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该博客内容展示了如何使用Java实现生成随机验证码的功能，包括创建BufferedImage对象、绘制随机文字、添加干扰线和噪点，并将验证码保存到Redis中。同时，通过Graphics2D进行文字旋转和颜色随机化，增加了验证码的复杂性和安全性。

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    /**
     *  获取随机 验证码
     * @param response
     * @param request
     */
    @GetMapping("/getCode")
    public void getVerificationCode(HttpServletResponse response, HttpServletRequest request) {
        try {
            int width = 200;
            int height = 69;
            BufferedImage verifyImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            String randomText = AuthCodeUtils.drawRandomText(width, height, verifyImg);
            ValueOperations<String, String> ops = redisTemplate.opsForValue();
            ops.set("AuthCode", randomText);

            response.setContentType("image/png");               //响应类型
            OutputStream os = response.getOutputStream();       //获取文件输出流
            ImageIO.write(verifyImg, "png", os);    //输出图片流

            os.flush();
            os.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

封装工具类

public class AuthCodeUtils {
    public static String drawRandomText(int width, int height, BufferedImage verifyImg) {
        Graphics2D graphics = (Graphics2D) verifyImg.getGraphics();
        graphics.setColor(Color.WHITE);                 // 验证码背景色
        graphics.fillRect(0, 0, width, height);     //填充背景
        graphics.setFont(new Font("微软雅黑", Font.BOLD, 40));

        //数字和字母组合
        String baseNumLetter ="123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNPQRSTUVWXYZ";
        StringBuffer sBuffer = new StringBuffer();
        int x = 10;  //旋转原点的 x 坐标
        String ch = "";
        Random random = new Random();
        for (int i = 0; i < 4; i++) {
            graphics.setColor(getRandomColor());
            //设置字体旋转角度
            int degree = random.nextInt() % 30;  //角度小于30度
            int dot = random.nextInt(baseNumLetter.length());
            ch = baseNumLetter.charAt(dot) + "";
            sBuffer.append(ch);
            //正向旋转
            graphics.rotate(degree * Math.PI / 180, x, 45);
            graphics.drawString(ch, x, 45);
            //反向旋转
            graphics.rotate(-degree * Math.PI / 180, x, 45);
            x += 48;
        }

        //画干扰线
        for (int i = 0; i < 6; i++) {
            // 设置随机颜色
            graphics.setColor(getRandomColor());
            // 随机画线
            graphics.drawLine(random.nextInt(width), random.nextInt(height),
                    random.nextInt(width), random.nextInt(height));
        }

        //添加噪点
        for (int i = 0; i < 30; i++) {
            int x1 = random.nextInt(width);
            int y1 = random.nextInt(height);
            graphics.setColor(getRandomColor());
            graphics.fillRect(x1, y1, 2, 2);
        }
        return sBuffer.toString();
    }

    /**
     * 随机取色
     */
    private static Color getRandomColor() {
        Random ran = new Random();
        Color color = new Color(ran.nextInt(256),
                ran.nextInt(256), ran.nextInt(256));
        return color;
    }
}