Kaptcha验证码组件

第一步：引入对应的组件信息
pom.xml中添加
<!-- Kaptcha验证码组件 -->
        <dependency>
            <groupId>com.github.penggle</groupId>
            <artifactId>kaptcha</artifactId>
            <version>2.3.2</version>
        </dependency>
第二步：在applicationContext.xml中添加设置信息
<!-- 配置Kaptcha -->
    <bean id="kaptchaProducer" class="com.google.code.kaptcha.impl.DefaultKaptcha">
        <property name="config">
            <bean class="com.google.code.kaptcha.util.Config">
                <constructor-arg>
                    <props>
                        <!--验证码图片不生成边框-->
                        <prop key="kaptcha.border">no</prop>
                        <!-- 验证码图片宽度为120像素 -->
                        <prop key="kaptcha.image.width">120</prop>
                        <!-- 验证码图片字体颜色为蓝色 -->
                        <prop key="kaptcha.textproducer.font.color">blue</prop>
                        <!-- 每个字符最大占用40像素 -->
                        <prop key="kaptcha.textproducer.font.size">40</prop>
                        <!-- 验证码包含4个字符 -->
                        <prop key="kaptcha.textproducer.char.length">4</prop>
                    </props>
                </constructor-arg>
            </bean>
        </property>
    </bean>

第三步：添加工具类KaptchaController.java
import java.awt.image.BufferedImage;
import java.io.IOException;
import javax.annotation.Resource;
import javax.imageio.ImageIO;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import com.google.code.kaptcha.Producer;
@Controller
public class KaptchaController {
    @Resource
    private Producer kaptchaProducer;
    @GetMapping("/verify_code")
    public void createVerifyCode(HttpServletRequest request , HttpServletResponse response) throws IOException {
        //响应立即过期
        response.setDateHeader("Expires",0);
        //不缓存任何图片数据
        response.setHeader("Cache-Control" , "no-store,no-cache,must-revalidate");
        response.setHeader("Cache-Control" , "post-check=0,pre-check=0");
        response.setHeader("Pragma" , "no-cache");
        response.setContentType("image/png");
        //生成验证码字符文本
        String verifyCode = kaptchaProducer.createText();
        request.getSession().setAttribute("kaptchaVerifyCode",verifyCode);
        System.out.println(request.getSession().getAttribute("kaptchaVerifyCode"));
        BufferedImage image = kaptchaProducer.createImage(verifyCode);//创建验证码图片
        ServletOutputStream out = response.getOutputStream();
        ImageIO.write(image, "png", out);//输出图片流
        out.flush();
        out.close();
    }
}

第四步：在前台需要的jsp页面的img标签中，调用对应路径即可
<img id="imgVerifyCode" src="/verify_code"
                             style=" 120px;height:50px;cursor: pointer">
添加对应的点击刷新功能
    //重新发送请求,刷新验证码
    function reloadVerifyCode(){
        //请在这里实现刷新验证码
        $("#imgVerifyCode").attr("src","/verify_code?ts=" + new Date().getTime());
    }
    
    //点击验证码图片刷新验证码
    $("#imgVerifyCode").click(function () {
        reloadVerifyCode();
    });

后台验证时：
    前台ajax提交，后台从HttpServletRequest request中获取：
　　String verifyCode = (String)request.getSession().getAttribute("kaptchaVerifyCode");
　　此处kaptchaVerifyCode 为验证码生成工具中的request 所添加的 request.getSession().setAttribute("kaptchaVerifyCode",verifyCode);

　　@PostMapping("/registe")
    @ResponseBody //vc:前台输入验证码  username:用户名 password:密码 nickname:昵称
    public Map registe(String vc, String username, String password , String nickname , HttpServletRequest request){
        //正确验证码
        String verifyCode = (String)request.getSession().getAttribute("kaptchaVerifyCode");
        //验证码对比
        Map result = new HashMap();
　　　　  //equalsIgnoreCase() 方法用于将字符串与指定的对象比较，不考虑大小写。
        if(vc == null || verifyCode == null || !vc.equalsIgnoreCase(verifyCode)){
            result.put("code", "VC01");
            result.put("msg", "验证码错误");
        }else{
            try {
                memberService.createMember(username, password, nickname);
                result.put("code", "0");
                result.put("msg", "success");
            }catch (BussinessException ex){
                ex.printStackTrace();
                result.put("code", ex.getCode());
                result.put("msg", ex.getMsg());
            }
        }
        return result;
    }