有哪些情况呢 我写的具体关键代码如下:
页面上:
<img class="validationCode_img" src="validationCode.do">
web.xml:
<servlet>
<servlet-name>validationCode</servlet-name>
<servlet-class>zh.userlogin.sample.ValidationCode</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>validationCode</servlet-name>
<url-pattern>/validationCode.do</url-pattern>
</servlet-mapping>