Jsp 无法在Google App Engine上部署Servlet应用程序

起初我已经成功地部署了它，但在运行它时遇到的问题是它找不到我的servlet文件来转发页面，然后我意识到我忘记在web.xml文件中配置servlet，因此我向web.xml文件添加了servlet标记，但当我再次尝试部署它时，它会显示以下消息

“错误：服务器错误 服务器遇到错误，无法完成您的请求。 请在30秒后重试。“

因此，我尝试删除web.xml文件中的servlet标记，然后可以第一次部署它。 因此，我认为问题是由servlet标记引起的，但我现在将其放回web.xml文件。我不知道该怎么办。请帮忙

这是web.xml文件

<?xml version="1.0" encoding="utf-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5">
  <servlet>
    <servlet-name>Cal</servlet-name>
    <servlet-class>Calculator</servlet-class>

  </servlet>

</web-app>

这是appengine-web.xml

<?xml version="1.0" encoding="utf-8"?>
<appengine-web-app xmlns="http://appengine.google.com/ns/1.0">
  <application>componentreport57</application>
  <version>2</version>

  <!--
    Allows App Engine to send multiple requests to one instance in parallel:
  -->
  <threadsafe>true</threadsafe>

  <!-- Configure serving/caching of GWT files -->
  <static-files>
    <include path="**" />

    <!-- The following line requires App Engine 1.3.2 SDK -->
    <include path="**.nocache.*" expiration="0s" />

    <include path="**.cache.*" expiration="365d" />
    <exclude path="**.gwt.rpc" />
  </static-files>

  <!-- Configure java.util.logging -->
  <system-properties>
    <property name="java.util.logging.config.file" value="WEB-INF/logging.properties"/>
  </system-properties>

  <!--
    HTTP Sessions are disabled by default. To enable HTTP sessions specify:

      <sessions-enabled>true</sessions-enabled>

    It's possible to reduce request latency by configuring your application to
    asynchronously write HTTP session data to the datastore:

      <async-session-persistence enabled="true" />

    With this feature enabled, there is a very small chance your app will see
    stale session data. For details, see
    http://code.google.com/appengine/docs/java/config/appconfig.html#Enabling_Sessions
  -->

</appengine-web-app>

组件报告57
2
真的

尝试充实计算器类。例如：

<servlet-class>cal.Calculator</servlet-class>

cal.Calculator

<servlet-class>cal.Calculator</servlet-class>