java生成随机验证码并转换成图片

2019/7/24 9:38:22 人评论 次浏览 分类:学习教程

1、设置随机字符范围
2、获取你想要的随机字符
3、将生成的随机字符转换成图片
4、调用
/**
* 使用到Algerian字体,系统里没有的话需要安装字体,字体只显示大写,去掉了1,0,i,o几个容易混淆的字符
*/
public static final String VERIFY_CODES = “23456789ABCDEFGHJKLMNPQRSTUVWXYZ”;

/**
* 使用系统默认字符源生成验证码
*
* @param verifySize 验证码长度
* @return
/
public static String generateVerifyCode(int verifySize) {
return generateVerifyCode(verifySize, VERIFY_CODES);
}
/
*
* 使用指定源生成验证码
*
* @param verifySize 验证码长度
* @param sources 验证码字符源
* @return
/
public static String generateVerifyCode(int verifySize, String sources) {
if (sources == null || sources.length() == 0) {
sources = VERIFY_CODES;
}
int codesLen = sources.length();
Random rand = new Random(System.currentTimeMillis());
StringBuilder verifyCode = new StringBuilder(verifySize);
for (int i = 0; i < verifySize; i++) {
verifyCode.append(sources.charAt(rand.nextInt(codesLen - 1)));
}
return verifyCode.toString();
}
/
*
* 输出指定验证码图片流
*
* @param w
* @param h
* @param os
* @param code
* @throws IOException
*/
public static void outputImage(int w, int h, OutputStream os, String code) throws IOException {
int verifySize = code.length();
BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
Random rand = new Random();
Graphics2D g2 = image.createGraphics();
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
Color[] colors = new Color[5];
Color[] colorSpaces = new Color[]{Color.WHITE, Color.CYAN,
Color.GRAY, Color.LIGHT_GRAY, Color.MAGENTA, Color.ORANGE,
Color.PINK, Color.YELLOW};
float[] fractions = new float[colors.length];
for (int i = 0; i < colors.length; i++) {
colors[i] = colorSpaces[rand.nextInt(colorSpaces.length)];
fractions[i] = rand.nextFloat();
}
Arrays.sort(fractions);
// 设置边框色
g2.setColor(Color.GRAY);
g2.fillRect(0, 0, w, h);

    Color c = getRandColor(200, 250);
    // 设置背景色
    g2.setColor(c);
    g2.fillRect(0, 2, w, h - 4);

    //绘制干扰线
    Random random = new Random();
    // 设置线条的颜色
    g2.setColor(getRandColor(160, 200));
    for (int i = 0; i < 20; i++) {
        int x = random.nextInt(w - 1);
        int y = random.nextInt(h - 1);
        int xl = random.nextInt(6) + 1;
        int yl = random.nextInt(12) + 1;
        g2.drawLine(x, y, x + xl + 40, y + yl + 20);
    }

    // 添加噪点
    // 噪声率
    float yawpRate = 0.05f;
    int area = (int) (yawpRate * w * h);
    for (int i = 0; i < area; i++) {
        int x = random.nextInt(w);
        int y = random.nextInt(h);
        int rgb = getRandomIntColor();
        image.setRGB(x, y, rgb);
    }
    // 使图片扭曲
    shear(g2, w, h, c);

    g2.setColor(getRandColor(100, 160));
    int fontSize = h - 4;
    Font font = new Font("Algerian", Font.ITALIC, fontSize);
    g2.setFont(font);
    char[] chars = code.toCharArray();
    for (int i = 0; i < verifySize; i++) {
        AffineTransform affine = new AffineTransform();
        affine.setToRotation(Math.PI / 4 * rand.nextDouble() * (rand.nextBoolean() ? 1 : -1), (w / verifySize) * i + fontSize / 2, h / 2);
        g2.setTransform(affine);
        g2.drawChars(chars, i, 1, ((w - 10) / verifySize) * i + 5, h / 2 + fontSize / 2 - 4);
    }

    g2.dispose();
    ImageIO.write(image, "jpg", os);
}

/**
* 生成验证码图片
* @param request
* @param response
* @return
* @throws IOException
*/
@RequestMapping(value = “/drawCodeImage”, method = {RequestMethod.GET, RequestMethod.POST})
public void drawImage(HttpServletRequest request, HttpServletResponse response){
response.setHeader(“Pragma”, “No-cache”);
response.setHeader(“Cache-Control”, “no-cache”);
response.setDateHeader(“Expires”, 0);
response.setContentType(“image/jpeg”);

    //生成随机字串
    String captcha = CaptchaUtil.generateVerifyCode(4);
    //存入session
    request.getSession().setAttribute(SystemConstants.SESSION_CAPTCHA_KEY, captcha.toLowerCase());
    //生成图片
    int w = 160, h = 60;
    try {
        CaptchaUtil.outputImage(w, h, response.getOutputStream(), captcha);
    } catch (IOException e) {
        log.info("验证码生成图片失败");
        e.printStackTrace();
    }
}

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