com.google.code.kaptcha如何引入

1. 下载com.google.code.kaptcha jar包，将其放置在项目的lib目录下。

2. 在项目的pom.xml文件中添加以下依赖：

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

3. 在web.xml中添加KaptchaServlet和KaptchaConfig配置：

<servlet>
    <servlet-name>KaptchaServlet</servlet-name>
    <servlet-class>com.google.code.kaptcha.servlet.KaptchaServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>KaptchaServlet</servlet-name>
    <url-pattern>/kaptcha.jpg</url-pattern>
</servlet-mapping>
<servlet>
    <servlet-name>KaptchaConfig</servlet-name>
    <servlet-class>com.google.code.kaptcha.servlet.KaptchaConfig</servlet-class>
    <init-param>
        <param-name>kaptcha.border</param-name>
        <param-value>yes</param-value>
    </init-param>
    <init-param>
        <param-name>kaptcha.border.color</param-name>
        <param-value>105,179,90</param-value>
    </init-param>
    <init-param>
        <param-name>kaptcha.textproducer.font.color</param-name>
        <param-value>blue</param-value>
    </init-param>
    <init-param>
        <param-name>kaptcha.image.width</param-name>
        <param-value>125</param-value>
    </init-param>
    <init-param>
        <param-name>kaptcha.image.height</param-name>
        <param-value>45</param-value>
    </init-param>
    <init-param>
        <param-name>kaptcha.textproducer.font.size</param-name>
        <param-value>30</param-value>
    </init-param>
    <init-param>
        <param-name>kaptcha.session.key</param-name>
        <param-value>KAPTCHA_SESSION_KEY</param-value>
    </init-param>
    <init-param>
        <param-name>kaptcha.textproducer.char.length</param-name>
        <param-value>4</param-value>
    </init-param>
    <init-param>
        <param-name>kaptcha.textproducer.font.names</param-name>
        <param-value>Arial,Courier</param-value>
    </init-param>
</servlet>

4. 在需要生成验证码的地方使用以下代码：

// 生成验证码
DefaultKaptcha kaptcha = new DefaultKaptcha();
String text = kaptcha.createText();
BufferedImage image = kaptcha.createImage(text);

// 将验证码存储在session中
HttpSession session = request.getSession();
session.setAttribute("kaptcha", text);

// 将验证码图片输出到页面
response.setContentType("image/jpeg");
ServletOutputStream outputStream = response.getOutputStream();
ImageIO.write(image, "jpg", outputStream);
outputStream.flush();
outputStream.close();