Java生成動态随機驗證碼

廢話不多說，直接上代碼！

/**
     * @Description: 擷取驗證碼圖檔
     * @params
     * @Author: czw
     * @return
     * @CreateDate: 2021/3/1 10:32
     */
    @RequestMapping("/get_verify_code")
    @ResponseBody
    public void getVerifyCode(String uuid, HttpServletResponse response) throws IOException {
        int width = 120; // 驗證碼圖檔寬度
        int height = 40; // 驗證碼圖檔長度
        int length = 4; // 驗證碼位數
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics g = image.getGraphics();
        Random random = new Random();
        g.setColor(VerifyCodeUtil.getRandColor(185, 250));
        g.fillRect(0, 0, width, height);
        g.setFont(new Font("Times New Roman", Font.ITALIC, 35));
        g.setColor(VerifyCodeUtil.getRandColor(160, 200));
        for (int i = 0; i < 155; i++) {
            int x = random.nextInt(width);
            int y = random.nextInt(height);
            int xl = random.nextInt(12);
            int yl = random.nextInt(12);
            g.drawLine(x, y, x + xl, y + yl);
        }

        StringBuilder sRand = new StringBuilder();
        for (int i = 0; i < length; i++) {
            String rand = String.valueOf(VerifyCodeUtil.getRandomString(random.nextInt(VerifyCodeUtil.randString.length())));
            sRand.append(rand);
            g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
            g.drawString(rand, 25 * i + 12, 32);
        }
        //7.将随機驗證碼存入redis緩存并設定過期時間，設定過期時間20分鐘
        stringRedisTemplate.opsForValue().set(uuid,sRand.toString(),60 * 20,TimeUnit.SECONDS);
        //8.設定響應頭通知浏覽器以圖檔的形式打開
        response.setContentType("image/jpeg");//等同于response.setHeader("Content-Type", "image/jpeg");
        //9.設定響應頭控制浏覽器不要緩存
        response.setDateHeader("expries", -1);
        response.setHeader("Cache-Control", "no-cache");
        response.setHeader("Pragma", "no-cache");
        //10.将圖檔寫給浏覽器
        ImageIO.write(image, "jpg", response.getOutputStream());
    }
           

上工具類

/**
 * @author czw
 * @version 1.0
 * @date 2021/3/1 9:31
 * @remark 生成驗證碼工具類
 */
public class VerifyCodeUtil {

    public static String randString = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";//随機字元串

    /**
     * 擷取随機的字元
     */
    public static String getRandomString(int num) {
        return String.valueOf(randString.charAt(num));
    }

    /**
     * 擷取顔色
     */
    public static Color getRandColor(int fc, int bc) {
        Random random = new Random();
        if (fc > 255)
            fc = 255;

        if (bc > 255)
            bc = 255;
        int r = fc + random.nextInt(bc - fc);
        int g = fc + random.nextInt(bc - fc);
        int b = fc + random.nextInt(bc - fc);
        return new Color(r, g, b);
    }

}
           

效果圖如下