Kaptcha 生成图形验证码

Kaptcha（卡普查）来完成验证码的生成。 Kaptcha是一个非常实用的验证码生成工具

    com.github.penggle
    kaptcha
    2.3.2

编写获取图形验证码的方法

private final DefaultKaptcha kaptcha;
/**
 * 获取图片验证码
 * @param httpServletRequest
 * @param httpServletResponse
 */
@GetMapping("/imageCode/{clientToken}")
public void getImageCode(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse,@PathVariable String clientToken) throws IOException {
    ByteArrayOutputStream jpegOutputStream = new ByteArrayOutputStream();
    String createText = kaptcha.createText();
    BufferedImage challenge = kaptcha.createImage(createText);
    ImageIO.write(challenge, "jpg", jpegOutputStream);
    byte[] captchaChallengeAsJpeg  = jpegOutputStream.toByteArray();
    httpServletResponse.setContentType("image/jpeg");
    ServletOutputStream responseOutputStream =
            httpServletResponse.getOutputStream();
    responseOutputStream.write(captchaChallengeAsJpeg);
    responseOutputStream.flush();
    responseOutputStream.close();
    //将验证码存入redis  2分钟超时
    redisTemplate.boundValueOps(clientToken).set(createText,120, TimeUnit.SECONDS);
}

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