Google Kaptcha 框架实现登录验证码功能（SSM 和 SpringBoot）

<!-- 验证码 -->

<!-- https: //mvnrepository测试数据/artifact/com.github.penggle/kaptcha -->

<dependency>

     <groupid>com.github.penggle</groupid>

     <artifactid>kaptcha</artifactid>

     <version> 2.3 . 2 </version>

</dependency>

<!-- 验证码相关属性的配置 -->

<servlet>

  <servlet-name>kaptcha</servlet-name>

  <servlet- class >com.google.code.kaptcha.servlet.kaptchaservlet</servlet- class >

  <!-- 定义 kaptcha 的样式 -->

  <!-- 是否有边框 -->

  <init-param>

   <param-name>kaptcha.border</param-name>

   <param-value>no</param-value>

  </init-param>

  <!-- 字体颜色 -->

  <init-param>

   <param-name>kaptcha.textproducer.font.color</param-name>

   <param-value>red</param-value>

  </init-param>

  <!-- 图片宽度 -->

  <init-param>

   <param-name>kaptcha.image.width</param-name>

   <param-value> 135 </param-value>

  </init-param>

  <!-- 图片高度 -->

  <init-param>

   <param-name>kaptcha.image.height</param-name>

   <param-value> 50 </param-value>

  </init-param>

  <!-- 使用哪些字符生成验证码 -->

  <init-param>

   <param-name>kaptcha.textproducer. char .string</param-name>

   <param-value>acdefhkprstwx345975</param-value>

  </init-param>

  <!-- 字体大小 -->

  <init-param>

   <param-name>kaptcha.textproducer.font.size</param-name>

   <param-value> 43 </param-value>

  </init-param>

  <!-- 干扰线的颜色 -->

  <init-param>

   <param-name>kaptcha.noise.color</param-name>

   <param-value>black</param-value>

  </init-param>

  <!-- 字符个数 -->

  <init-param>

   <param-name>kaptcha.textproducer. char .length</param-name>

   <param-value> 4 </param-value>

  </init-param>

  <!-- 字体 -->

  <init-param>

   <param-name>kaptcha.textproducer.font.names</param-name>

   <param-value>arial</param-value>

  </init-param>

</servlet>

<servlet-mapping>

  <servlet-name>kaptcha</servlet-name>

  <!-- 外部访问路径 -->

  <url-pattern>/kaptcha</url-pattern>

</servlet-mapping>

div class = "item-inner" >

  <div class = "item-title label" >验证码</div>

  <input type= "text" id= "j_captcha" placeholder= "验证码" >

  <div class = "item-input" >

   <img id= "captcha_img" alt= "点击更换" title= "点击更换"

     onclick= "changeverifycode(this)" src= "kaptcha" />

  </div>

</div>

function changeverifycode(img){

     img.src= "kaptcha?" + math.floor(math.random()* 100 );

}

public class codeutil {

  public static boolean checkverifycode(httpservletrequest request){

   string verifycodeexpected = (string)request.getsession().getattribute(

     com.google.code.kaptcha.constants.kaptcha_session_key);

   //这里相当于 request.getparameter("verifycodeactual");

   string verifycodeactual = httpservletrequestutil.getstring(request, "verifycodeactual" );

   if (verifycodeactual == null || verifycodeactual.equals(verifycodeexpected)){

    return false ;

   }

   return true ;

  }}

if (!codeutil.checkverifycode(request)){

     modelmap.put( "success" , false );

     modelmap.put( "errmsg" , "输入了错误的验证码" );

     return modelmap;

}

     modelmap.put( "success" , false );

     modelmap.put( "errmsg" , "输入了错误的验证码" );

     return modelmap;

}

package com.example.demo.config;

import com.google.code.kaptcha.impl.defaultkaptcha;

import com.google.code.kaptcha.util.config;

import org.springframework.context.annotation.bean;

import org.springframework.context.annotation.configuration;

import java.util.properties;

@configuration

public class kaptchacontroller {

  @bean (name= "captchaproducer" )

  public defaultkaptcha getkaptchabean(){

   defaultkaptcha defaultkaptcha= new defaultkaptcha();

   properties properties= new properties();

   properties.setproperty( "kaptcha.border" , "yes" );

   properties.setproperty( "kaptcha.border.color" , "105,179,90" );

   properties.setproperty( "kaptcha.textproducer.font.color" , "blue" );

   properties.setproperty( "kaptcha.image.width" , "125" );

   properties.setproperty( "kaptcha.image.height" , "45" );

   properties.setproperty( "kaptcha.session.key" , "code" );

   properties.setproperty( "kaptcha.textproducer.char.length" , "4" );

   properties.setproperty( "kaptcha.textproducer.font.names" , "宋体,楷体,微软雅黑" );

   config config= new config(properties);

   defaultkaptcha.setconfig(config);

   return defaultkaptcha;

  }

}

package com.example.demo.controller;

import com.google.code.kaptcha.constants;

import com.google.code.kaptcha.producer;

import org.springframework.beans.factory.annotation.autowired;

import org.springframework.stereotype.controller;

import org.springframework.web.bind.annotation.getmapping;

import javax.imageio.imageio;

import javax.servlet.servletoutputstream;

import javax.servlet.http.httpservletresponse;

import javax.servlet.http.httpsession;

import java.awt.image.bufferedimage;

@controller

public class chacontroller {

  @autowired

  private producer captchaproducer;

  @getmapping ( "/getkaptchaimage" )

  public void getkaptchaimage(httpservletresponse response,httpsession session) throws exception {

   response.setdateheader( "expires" , 0 );

   // set standard http/1.1 no-cache headers.

   response.setheader( "cache-control" , "no-store, no-cache, must-revalidate" );

   // set ie extended http/1.1 no-cache headers (use addheader).

   response.addheader( "cache-control" , "post-check=0, pre-check=0" );

   // set standard http/1.0 no-cache header.

   response.setheader( "pragma" , "no-cache" );

   // return a jpeg

   response.setcontenttype( "image/jpeg" );

   // create the text for the image

   string captext = captchaproducer.createtext();

   // store the text in the session

   //request.getsession().setattribute(constants.kaptcha_session_key, captext);

   //将验证码存到session

   session.setattribute(constants.kaptcha_session_key, captext);

   // create the image with the text

   bufferedimage bi = captchaproducer.createimage(captext);

   servletoutputstream out = response.getoutputstream();

   // write the data out

   imageio.write(bi, "jpg" , out);

   try {

    out.flush();

   } finally {

    out.close();

   }

  }

}

<img id= "captcha_img" alt= "点击更换" title= "点击更换"

     onclick= "changeverifycode(this)" src= "getkaptchaimage" />