Implementing graphic verification code tool class based on Java

package ;

import .slf4j.Slf4j;

import ;
import .*;
import ;
import ;
import ;
import ;

/**
  * Verification code tool class
  *
  * @author wangbo
  * @since 2024/10/29
  */
@Slf4j
public class CaptchaGeneratorUtil {

    private CaptchaGeneratorUtil() {
        // ...
    }

    public static void main(String[] args) throws IOException {
        // Generate 4-bit random digital verification code        String text = generateRandomCode();
        // Create verification code picture        BufferedImage image = createImage(text);
        // Save the picture to the file        (image, "png", new File(""));
    }

    private static final SecureRandom RANDOM = new SecureRandom();

    /**
      * Generate 4-digit random number letter verification code
      */
    public static String generateRandomCode() {
        StringBuilder code = new StringBuilder();
        for (int i = 0; i < 4; i++) {
            int i1 = (3);
            if (i1 == 0) {
                ((char) ((26) + 65));
            } else if (i1 == 1) {
                ((char) ((26) + 97));
            } else {
                ((10));
            }
        }
        ("The generated verification code text text = {}", code);
        return ();
    }

    /**
      * Create verification code picture
      */
    public static BufferedImage createImage(String text) {
        ("Text of the verification code image to be generated text = {}", text);
        int width = 75;
        int height = 25;
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        // Use Graphics2D for better graphics control        Graphics2D g2d = ();

        try {
            // Set background color            (new Color(0xDCDCDC));
            (0, 0, width, height);

            // Set font and color            (new Font("Arial", , 20));
            (new Color(0x004000));

            // Make sure the text does not exceed the image boundary            FontMetrics fm = ();
            int textWidth = (text);
            // Chinese text            int x = (width - textWidth) / 2;
            // Centered text (baseline alignment)            int y = (height - ()) / 2 + ();

            (text, x, y);

            // Add noise lines            for (int i = 0; i < 5; i++) {
                (new Color((255), (255), (255)));
                ((width), (height), (width), (height));
            }

            // Set rendering prompts to improve image quality (optional)            (RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        } finally {
            // Make sure to release Graphics2D resources after the try block            ();
        }

        return image;
    }

    private static final String CAPTCHA_PREFIX = "captcha:";

    public static String generateCaptchaRedisKey(String key) {
        return CAPTCHA_PREFIX + key;
    }
}

/**
  * Generate image verification code
  *
  * @param key UUID string
  */
@GetMapping("/captcha/generator/{key}")
public void captchaGenerator(@PathVariable("key") String key, HttpServletResponse response) throws BaseException {
    (key, response);
}

public void captchaGenerator(String key, HttpServletResponse response) throws BaseException {
    // Check whether the key's verification code already exists    String captchaRedisKey = (key);
    boolean hasKey = ((captchaRedisKey));
    if (hasKey) {
        throw new BaseException(ErrorCode.USER_KEY_REPETITION);
    }
    String captcha = ();
    BufferedImage image = (captcha);
    //Set the verification code, valid for 1 minute    ().set(captchaRedisKey, captcha, 60L, );
    ("image/jpeg");
    try (ServletOutputStream out = ()) {
        (image, "JPEG", out);
    } catch (IOException e) {
        throw new RuntimeException(e);
    }
}

//Calculation verification codeString key = ();
String captcha = ();
if ((key) || (captcha)) {
    throw new BaseException(ErrorCode.USER_KEY_OR_CAPTCHA_NOT_FOUND);
}
String captchaRedisKey = (key);
String redisCaptcha = ().get(captchaRedisKey);
if ((redisCaptcha) || !(redisCaptcha)) {
    throw new BaseException(ErrorCode.USER_CAPTCHA_ERROR);
} else {
    //Delete the verification code cache    (captchaRedisKey);
}