springboot使用PageHelper分页插件和验证码功能( 三 ) _电脑

byte[] captchaChallengeAsJpeg = null;
ByteArrayOutputStream jpegOutputStream = new ByteArrayOutputStream();
try {
//出产验证码字符串并保留到session中
String createText = defaultKaptcha.createText();
httpServletRequest.getSession().setAttribute("vrifyCode", createText);
//利用出产的验证码字符串返回一个BufferedImage对象并转为byte写入到byte数组中
BufferedImage challenge = defaultKaptcha.createImage(createText);
ImageIO.write(challenge, "jpg", jpegOutputStream);
} catch (IllegalArgumentException e) {
httpServletResponse.sError(HttpServletResponse.SC_NOT_FOUND);
return;
}
//界说response输出类型为image/jpeg类型，利用response输出流输出图片的byte数组
captchaChallengeAsJpeg = jpegOutputStream.toByteArray();
httpServletResponse.setHeader("Cache-Control", "no-store");
httpServletResponse.setHeader("Pragma", "no-cache");
httpServletResponse.setDateHeader("Expires", 0);
httpServletResponse.setContentType("image/jpeg");
ServletOutputStream responseOutputStream =
httpServletResponse.getOutputStream();
responseOutputStream.write(captchaChallengeAsJpeg);
responseOutputStream.flush();
responseOutputStream.close();
}

6HTML页面利用：