java相关：kaptcha验证码使用方法详解

发布于 2020-6-7|

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摘记: 本文为大家分享了kaptcha验证码的使用方法，供大家参考，具体内容如下1.首先在pom.xml文件中导入Maven依赖

```jfx

com.github.penggle

kaptcha

..

本文为大家分享了kaptcha验证码的使用方法，供大家参考，具体内容如下1.首先在pom.xml文件中导入Maven依赖

```jfx

com.github.penggle

kaptcha

2.3.2

```

2.在web.xml文件中配置一个servlet

```xml

Kaptcha

com.google.code.kaptcha.servlet.KaptchaServlet

kaptcha.border

no

kaptcha.textproducer.font.color

red

kaptcha.image.width

135

kaptcha.textproducer.char.string

ACDEFHKPRSTWX345679

kaptcha.image.height

50

kaptcha.textproducer.font.size

43

kaptcha.noise.color

black

kaptcha.textproducer.char.length

4

kaptcha.textproducer.font.names

Arial

Kaptcha

/Kaptcha

```

3.页面代码如下

```xhtml

验证码

```

向后端提交数据

```javascript

var verifyCodeActual = $('#j_captcha').val();

if (!verifyCodeActual) {

$.toast('请输入验证码！');

return;

}

formData.append("verifyCodeActual", verifyCodeActual);

```

4.js交互

```javascript

function changeVerifyCode(img) {

img.src = "../Kaptcha?" + Math.floor(Math.random() * 100);

}

```

5.后端验证

```java

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;

}

}

```

```java

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;

}

}

}

```