这期内容当中小编将会给大家带来有关使用kaptcha怎么实现一个验证码功能，文章内容丰富且以专业的角度为大家分析和叙述，阅读完这篇文章希望大家可以有所收获。
1.首先在pom.xml文件中导入Maven依赖
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<dependency>
<groupId>com.github.penggle</groupId>
<artifactId>kaptcha</artifactId>
<version>2.3.2</version>
</dependency>2.在web.xml文件中配置一个servlet
<servlet>
<!-- 生成图片的Servlet -->
<servlet-name>Kaptcha</servlet-name>
<servlet-class>com.google.code.kaptcha.servlet.KaptchaServlet</servlet-class>
<!-- 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>
<!-- 使用哪些字符生成验证码 -->
<init-param>
<param-name>kaptcha.textproducer.char.string</param-name>
<param-value>ACDEFHKPRSTWX345679</param-value>
</init-param>
<!-- 图片高度 -->
<init-param>
<param-name>kaptcha.image.height</param-name>
<param-value>50</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>
<!-- 使用哪些字体 -->
<init-param>
<param-name>kaptcha.textproducer.font.names</param-name>
<param-value>Arial</param-value>
</init-param>
</servlet>
<!-- 映射的url -->
<servlet-mapping>
<servlet-name>Kaptcha</servlet-name>
<url-pattern>/Kaptcha</url-pattern>
</servlet-mapping>3.页面代码如下
<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" />
</div>
</div>向后端提交数据
var verifyCodeActual = $('#j_captcha').val();
if (!verifyCodeActual) {
$.toast('请输入验证码！');
return;
}
formData.append("verifyCodeActual", verifyCodeActual);4.js交互
function changeVerifyCode(img) {
img.src = "../Kaptcha?" + Math.floor(Math.random() * 100);
}5.后端验证
import javax.servlet.http.HttpServletRequest;
public class CodeUtil {
public static boolean checkVerifyCode(HttpServletRequest request) {
String verifyCodeExpected = (String) request.getSession().getAttribute(
com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY);
String verifyCodeActual = HttpServletRequestUtil.getString(request,
"verifyCodeActual");
if (verifyCodeActual == null
|| !verifyCodeActual.equalsIgnoreCase(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;
}
}
}上述就是小编为大家分享的使用kaptcha怎么实现一个验证码功能了，如果刚好有类似的疑惑，不妨参照上述分析进行理解。如果想知道更多相关知识，欢迎关注亿速云行业资讯频道。
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