图片验证的SERVLET

<servlet><br/> <servlet-name>checkimage</servlet-name><br/> <servlet-class>com.flt.util.ImageServlet</servlet-class><br/> <init-param><br/> <param-name>width</param-name><br/> <param-value>60</param-value><br/> </init-param><br/> <init-param><br/> <param-name>height</param-name><br/> <param-value>20</param-value><br/> </init-param><br/> </servlet><br/> <br/> <servlet-mapping><br/> <servlet-name>checkimage</servlet-name><br/> <url-pattern>/checkimage</url-pattern><br/> </servlet-mapping><br/>************************************<br/>session.getAttribute("rand");<br/>得到严整的时图片数据