Kaptcha验证码SSM实现

<!--kaptcha验证码插件-->
      <dependency>
          <groupId>com.github.penggle</groupId>
          <artifactId>kaptcha</artifactId>
          <version>2.3.2</version>
      </dependency>

import javax.servlet.http.HttpServletRequest;
public class CodeUtil { 
   
    public static boolean checkVerifyCode(HttpServletRequest request) { 
   
    	//验证码图片字符串
        String verifyCodeExpected = (String)request.getSession().getAttribute(com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY);
        
        /** *验证码框内字符串，j_captcha为login.jsp上验证码框input的name， *除了这个需要改换成自己的name，其他可以直接套用 *HttpServletRequestUtil是一个工具类 */
        String verifyCodeActual = HttpServletRequestUtil.getString(request, "j_captcha");
        
        if(verifyCodeActual == null || !verifyCodeActual.equals(verifyCodeExpected)) { 
   
            return false;
        }
        return true;
    }
}

import javax.servlet.http.HttpServletRequest;

public class HttpServletRequestUtil { 
   
    public static int getInt(HttpServletRequest request, String name) { 
   

        try { 
   
            return Integer.decode(request.getParameter(name));
        } catch (Exception e) { 
   
            return -1;
        }
    }

    public static long getLong(HttpServletRequest request, String name) { 
   

        try { 
   
            return Long.valueOf(request.getParameter(name));
        } catch (Exception e) { 
   
            return -1;
        }
    }

    public static Double getDouble(HttpServletRequest request, String name) { 
   

        try { 
   
            return Double.valueOf(request.getParameter(name));
        } catch (Exception e) { 
   
            return -1d;
        }
    }

    public static Boolean getBoolean(HttpServletRequest request, String name) { 
   

        try { 
   
            return Boolean.valueOf(request.getParameter(name));
        } catch (Exception e) { 
   
            return false;
        }
    }

    public static String getString(HttpServletRequest request, String name) { 
   
        try { 
   
            String result = request.getParameter(name);
            if (result != null) { 
   
                result = result.trim();
            }
            if ("".equals(result))
                result = null;
            return result;
        } catch (Exception e) { 
   
            return null;
        }

    }
}

if(!CodeUtil.checkVerifyCode(request)) { 
   
	msg = "验证码错误";
	//验证码为空或验证码错误返回字段，可以自己在登陆jsp界面增加验证码框内不为空的错误显示
}else { 
   
    return "redirect:/testuser/main";
    //验证通过，重定向到用户主页，可以换成自己的指向用户主页方式
}

//验证码框和验证码图片的代码，直接插入到登陆的验证表单里也就是用户名和密码下面
<div class="item-inner">
    <label for="j_captcha" class="item-title label">验证码</label>
    <input id="j_captcha" name="j_captcha" type="text" class="form-control in" 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" />
            /**这里的src值需与web.xml里设置的kaptcha设置里的url-pattern * 相同,可以不用改动直接用，前提是文件结构如下图 */
        </div>
</div>

//这个可以直接套用，jquery对象依照上面进行设置
<script>

    $('#submit').click (
        function() { 
   
        var formData = new FormData();
        var verifyCodeActual = $('#j_captcha').val();
        //点击提交时，判断验证码是否为空，如果为空，提示输入验证码
        if (!verifyCodeActual) { 
   
            alert('请输入验证码');
            return;
        }
        //如果不为空，将验证码塞进formData里面去
        formData.append('verifyCodeActual', verifyCodeActual);

        //不管提交成功与否，验证码都会更换
        $('#captcha_img').click();
    });

    function changeVerifyCode(img) { 
   
        img.src = "../Kaptcha?" + Math.floor(Math.random() * 100);
        /*利用随机数进行验证码图片替换，这里的src也是要与web.xml里的一致， 要改动的话一起改 */
    }

</script>

<!-- 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 就是这里，需要改动jsp里src值的话这里也要改-->
        <url-pattern>/Kaptcha</url-pattern>
    </servlet-mapping>