vaadin - 无法加载应用程序类

Question

我得到javax.servlet.ServletException：无法加载应用程序类：com.example.App 当我尝试在本地Tomcat 7应用程序服务器上运行它时。

这是堆栈跟踪：（已满）

javax.servlet.ServletException: Failed to load application class: com.example.App 
    com.vaadin.terminal.gwt.server.ApplicationServlet.init(ApplicationServlet.java:71) 
    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472) 
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98) 
    org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927) 
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407) 
    org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1001) 
    org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:579) 
    org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310) 
    java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) 
    java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) 
    java.lang.Thread.run(Thread.java:722) 

这是我的web.xml：

<?xml version="1.0" encoding="UTF-8"?> 
    <web-app xmlns="http://java.sun.com/xml/ns/j2ee" 
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
     xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 
     http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd" 
     version="2.4"> 
    <servlet> 
     <servlet-name>ApplicationServlet</servlet-name> 
     <servlet-class>com.vaadin.terminal.gwt.server.ApplicationServlet</servlet-class> 
     <init-param> 
      <param-name>application</param-name> 
      <param-value>com.example.App</param-value> 
     </init-param> 
    </servlet> 
    <servlet-mapping> 
     <servlet-name>ApplicationServlet</servlet-name> 
     <url-pattern>/*</url-pattern> 
    </servlet-mapping> 

</web-app> 

App.class是在WEB-INF /班/ COM /例子/：

package com.example; 

import com.vaadin.Application; 
import com.vaadin.ui.Label; 
import com.vaadin.ui.Window; 

public class App extends Application { 

    @Override 
    public void init() { 
     Window main = new Window("Hello"); 
     setMainWindow(main); 
     main.addComponent(new Label("Hello, world!")); 

    } 
} 

我做错了什么？

你可以给我任何手动的分步部署？

P.S.更新。

Answer 1

WEB-INF/lib中的vaadin-xx.yy.zz.jar是否存在？ 它需要。