利用java实现简单的验证码
AbstractKaptchar kaptchar = new SimpleKaptchar();
// 创建验证码,指定证码长度与字符类型
kaptchar.createKaptchar(24, AbstractKaptchar.UPPER_LETTER);
resp.setDateHeader("Expires", 0);
resp.setHeader("Cache-Control",
"no-store, no-cache, must-revalidate");
resp.addHeader("Cache-Control", "post-check=0, pre-check=0");
resp.setHeader("Pragma", "no-cache");
resp.setContentType("image/jpeg");
ServletOutputStream out = null;
try {
out = resp.getOutputStream();
ImageIO.write(kaptchar.getImage(), "jpg", out);
LOGGER.info("captcha:{}",kaptchar.getCode());
out.flush();
out.close();
}catch (Exception e) {
LOGGER.error(e.getMessage(),e);
}- 以上局部代码来自于web接口调用的使用方式,resp 是在web应用中常见的的HttpServletResponse
- 24个字符
- 4个字符

