谷歌开源组件kaptcha生成验证码

<servlet>

<servlet-name>kaptcha</servlet-name>

<servlet-class>com.google.code.kaptcha.servlet.KaptchaServlet</servlet-class>

<init-param>

<description>图片宽 120</description>

<param-name>kaptcha.image.width</param-name>

<param-value>120</param-value>

</init-param>

<init-param>

<description>图片高 38</description>

<param-name>kaptcha.image.height</param-name>

<param-value>38</param-value>

</init-param>

<init-param>

<description> session中存放验证码的key键 </description>

<param-name>kaptcha.session.key</param-name>

<param-value>KAPTCHA_SESSION_KEY</param-value>

</init-param>

<init-param>

<description>字体大小 30px.</description>

<param-name>kaptcha.textproducer.font.size</param-name>

<param-value>30</param-value>

</init-param>

<init-param>

<description>验证码长度4</description>

<param-name>kaptcha.textproducer.char.length</param-name>

<param-value>4</param-value>

</init-param>

<init-param>

<description>文本集合，验证码值从此集合中获取</description>

<param-name>kaptcha.textproducer.char.string</param-name>

<param-value>1234567890</param-value>

</init-param>

<init-param>

<description> 字体颜色，合法值： r,g,b 或者 white,black,blue. </description>

<param-name>kaptcha.textproducer.font.color</param-name>

<param-value>blue</param-value>

</init-param>

</servlet>

<servlet-mapping>

<servlet-name>kaptcha</servlet-name>

<url-pattern>/randomcode.jpg</url-pattern>

</servlet-mapping>

用户名:

<input type="text" name="userName" />

<br /> <br />

密　码:

<input type="password" name="password" />

<br /> <br />

验证码:

<img src="randomcode.jpg" />