没有出现500错误？？？

<?xml version="1.0" encoding="UTF-8"?>

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
        version="3.1">
   <display-name>Weixin</display-name>

   <servlet>
       <servlet-name>WeixinServlet</servlet-name>
       <servlet-class>com.weixin.servlet.WeixinServlet</servlet-class>
   </servlet>

   <servlet-mapping>
       <servlet-name>WeixinServlet</servlet-name>
       <url-pattern>/wx.do</url-pattern>
   </servlet-mapping>

</web-app>