java实现获取验证码工具类

//验证码

public void crimg(HttpServletRequest request, HttpServletResponse response) throws IOException {
//发送验证码对象
ConfigurableCaptchaService cs = new ConfigurableCaptchaService();

Random random = new Random();

//发送不同显示型式的验证码
switch (random.nextInt(5)) {
case 0:
cs.setFilterFactory(new CurvesRippleFilterFactory(cs.getColorFactory()));
break;
case 1:
cs.setFilterFactory(new MarbleRippleFilterFactory());
break;
case 2:
cs.setFilterFactory(new DoubleRippleFilterFactory());
break;
case 3:
cs.setFilterFactory(new WobbleRippleFilterFactory());
break;
case 4:
cs.setFilterFactory(new DiffuseRippleFilterFactory());
break;
}
HttpSession session = request.getSession(false);
if (session == null) {
session = request.getSession();
}

//控制不缓存
response.setContentType("image/png");
response.setHeader("Cache-Control", "no-cache, no-store");
response.setHeader("Pragma", "no-cache");
long time = System.currentTimeMillis();
response.setDateHeader("Last-Modified", time);
response.setDateHeader("Date", time);
response.setDateHeader("Expires", time);

//获取验证码
String token = EncoderHelper.getChallangeAndWriteImage(cs, "png", response.getOutputStream());
session.setAttribute("token", token);
}

<!--html-->
<img src="URL" alt="" style="width: 70px;height: 40px;" id="verfyImg" onclick="getImg()" />
/* js代码 */
function getImg(){
var url = 'URL?_t='+Math.random();
$("#verfyImg").attr("src",url);
}