1.

首先在pom.xml中导入依赖

com.github.penggle

kaptcha

2.3.2

2.

在web.xml中设置

Kaptcha

com.google.code.kaptcha.servlet.KaptchaServlet

kaptcha.border

no

kaptcha.textproducer.font.color

red

kaptcha.image.width

135

kaptcha.textproducer.char.string

ACDEFHKPRSTWX345679

kaptcha.image.height

50

kaptcha.textproducer.font.size

43

kaptcha.noise.color

black

kaptcha.textproducer.char.length

4

kaptcha.textproducer.font.names

Arial

Kaptcha

/Kaptcha

3.

前端页面

登录

4.

后台controller层中

@RequestMapping(value="/subLogin",method=RequestMethod.POST)

public String sublogin(HttpServletRequest request,String verifyCodeActual,Model model){

//System.out.println(verifyCodeActual);

//System.out.println(request.getSession().getAttribute(com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY));

if(!CodeUtil.checkVerifyCode(request,verifyCodeActual)){

model.addAttribute("msg","验证码输入有误");

return "/showuserpage/userLogin";

}

return "/showuserpage/userIndex";

}

定义一个验证验证码的util类

public class CodeUtil {

public static boolean checkVerifyCode(HttpServletRequest request,String verifyCodeActual){

String verifyCodeExpected = (String) request.getSession()

.getAttribute(com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY);

//String verifyCodeActual = HttpServletRequestUtil.getString(request, "verifyCodeActual");

if(verifyCodeActual == null || !verifyCodeActual.equals(verifyCodeExpected)){

return false;

}

return true;

}

}