SpringMvc使用GoogleKaptcha生成验证码

<dependency> 
  <groupId>com.google.code.kaptcha</groupId> 
  <artifactId>kaptcha</artifactId> 
  <version>2.3.2</version> 
</dependency>

<dependency> 
  <groupId>com.github.penggle</groupId> 
  <artifactId>kaptcha</artifactId> 
  <version>2.3.2</version> 
</dependency>

<!-- google kaptcha的相关配置-->
  <bean id="captchaProducer" class="com.google.code.kaptcha.impl.DefaultKaptcha"> 
    <property name="config"> 
      <bean class="com.google.code.kaptcha.util.Config"> 
        <constructor-arg> 
          <props> 
            <!-- 是否有边框 可选yes 或者 no --> 
            <prop key="kaptcha.border">yes</prop> 
            <!-- 边框颜色 -->
            <prop key="kaptcha.border.color">105,179,90</prop> 
            <!-- 验证码文本字符颜色 -->
            <prop key="kaptcha.textproducer.font.color">blue</prop> 
            <!-- 验证码文本字符大小 -->
            <prop key="kaptcha.textproducer.font.size">45</prop> 
            <!-- 验证码图片的宽度 默认200 -->
            <prop key="kaptcha.image.width">125</prop> 
            <!-- 验证码图片的高度 默认50 -->
            <prop key="kaptcha.image.height">45</prop> 
            <!-- 验证码文本字符长度 默认为5 -->
            <prop key="kaptcha.textproducer.char.length">4</prop> 
            <!-- 验证码文本字体样式 默认为new Font("Arial", 1, fontSize), new Font("Courier", 1, fontSize) -->
            <prop key="kaptcha.textproducer.font.names">宋体,楷体,微软雅黑</prop> 
          </props> 
        </constructor-arg> 
      </bean> 
    </property> 
  </bean>

package com.ccg.controller;

import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.PrintWriter;

import javax.annotation.Resource;
import javax.imageio.ImageIO;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.ModelAndView;

import com.google.code.kaptcha.Constants;
import com.google.code.kaptcha.Producer;

@Controller
@RequestMapping("captcha")
public class CaptchaController {

  @Resource
  private Producer captchaProducer;
  /**
   *       
   *        获取验证码图片
   * @author     ccg
   * @param     request
   * @param     response
   * @return
   * @throws     IOException
   * Created    2017年1月17日 下午5:07:28
   */
  @RequestMapping("getCaptchaCode")
  public ModelAndView getCaptchaCode(HttpServletRequest request, HttpServletResponse response) throws IOException{
    HttpSession session = request.getSession();
    
    response.setDateHeader("Expires", 0); 
    response.setHeader("Cache-Control", "no-store, no-cache, must-revalidate"); 
    response.addHeader("Cache-Control", "post-check=0, pre-check=0"); 
    response.setHeader("Pragma", "no-cache"); 
    response.setContentType("image/jpeg"); 
    
    //生成验证码文本
    String capText = captchaProducer.createText(); 
    session.setAttribute(Constants.KAPTCHA_SESSION_KEY, capText);
    System.out.println("生成验证码文本===="+capText);
    //利用生成的字符串构建图片
    BufferedImage bi = captchaProducer.createImage(capText);
    ServletOutputStream out = response.getOutputStream(); 
    ImageIO.write(bi, "jpg", out); 
    
    try { 
      out.flush(); 
    } finally { 
      out.close(); 
    }
    return null;
  }
  
  /**
   *       
   *        前端输入的验证码与生成的对比
   * @author     ccg
   * @param     request
   * @param     response
   * @param     captchaCode
   * Created    2017年1月17日 下午5:34:23
   */
  @RequestMapping("checkCaptchaCode")
  public void checkCaptchaCode(HttpServletRequest request, HttpServletResponse response,@RequestParam("captchaCode") String captchaCode){
    System.out.println("页面输入验证码===="+captchaCode);
    
    response.setCharacterEncoding("UTF-8");
    response.setHeader("Pragma", "No-cache");
    response.setHeader("Cache-Control", "no-cache");
    response.setDateHeader("Expires", 0);
    
    String generateCode =(String) request.getSession().getAttribute(Constants.KAPTCHA_SESSION_KEY);
    String result = "";
    if(generateCode.equals(captchaCode)){
      result = "验证成功";
    }else{
      result = "输入错误";
    }
    PrintWriter out = null;
    try {
      out = response.getWriter();
    } catch (IOException e) {
      e.printStackTrace();
    }
    out.print(result);
    out.flush();
  }
}

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<script src="${pageContext.request.contextPath}/js/jquery.min.js" type="text/javascript"></script>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
  生成的验证码：<img id="changeCaptcha" src="http://127.0.0.1/captcha/getCaptchaCode.htm"> <a href="javascript:changeCaptcha()" rel="external nofollow" >看不清，换一张</a>
  <br>
  <br>
  请输入验证码：<input id="captchaCode" type="text"> <input type="button" value="提交验证" onclick="checkCaptcha()">
</body>
<script type="text/javascript">
//获取验证码图片 
function changeCaptcha(){
  $("#changeCaptcha").attr("src","http://127.0.0.1/captcha/getCaptchaCode.htm");
}
//验证输入的验证码 
function checkCaptcha(){
  var captchaCode = $("#captchaCode").val();
  $.ajax({
    type:'post',
    async : false,
    url:'http://127.0.0.1/captcha/checkCaptchaCode.htm',
    data:{"captchaCode" : captchaCode},
    success:function(res){
      alert(res);
    }
  });
}
</script>
</html>