Servlets java.lang.ClassNotFoundException:Servlet.controller.MainController

我正在做一个在线考试项目，我正在使用jsp和servlet。但通过xml映射使用servlet对我不起作用。每当我转到url并写入jsp名称时，它就会打开，因为我在servlet中给出了url模式注释。但当我尝试运行整个项目时，它会给我以下错误：

HTTP Status 500 - Error instantiating servlet class Servlet.controller.MainController

type Exception report

message Error instantiating servlet class Servlet.controller.MainController

description The server encountered an internal error that prevented it from fulfilling this request.

exception

javax.servlet.ServletException: Error instantiating servlet class Servlet.controller.MainController
    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
    org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
    org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:673)
    org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1500)
    org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1456)
    java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    java.lang.Thread.run(Thread.java:748)
root cause

java.lang.ClassNotFoundException: Servlet.controller.MainController
    org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1333)
    org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1167)
    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
    org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
    org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:673)
    org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1500)
    org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1456)
    java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    java.lang.Thread.run(Thread.java:748)
note The full stack trace of the root cause is available in the Apache Tomcat/8.0.27 logs.

Apache Tomcat/8.0.27 

下面是我的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" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>OnlineQuiz</display-name>
  <welcome-file-list>
    <welcome-file>home</welcome-file>
  </welcome-file-list>
  <servlet>
    <servlet-name>home</servlet-name>
    <servlet-class>Servlet.controller.MainController</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>home</servlet-name>
    <url-pattern>/home</url-pattern>
  </servlet-mapping>
</web-app> 

我担心错误可能是由于我的servlet的位置。。。因为这是我第一次使用servlet。 这是我的项目的文件层次结构。 …对不起，我无法上传它的照片

这门课是公共课吗？

---

如果不是，则将其公开，如果已经公开，则将相关代码与包一起发布

将目录截图添加到问题中。异常明确表示找不到指定的类。答案取决于编译类和构建WAR文件的具体方式。手动？还是使用IDE？那是哪一个呢？这一信息在问题中缺失。