请教高手，在TOMCAT下运行SERVLET需要怎么配置？在线等。
我在TOMCAT的WEB下调用了一个JSP页面，然后把SERVLET放到\webapps\web\WEB-INF\classes里面，在SERVER.XML中也把context项改为如下（我的包名是untitled2）

<Context path= "/untitled2 "

docBase= "webapps/untitled2 "

crossContext= "false "

debug= "0 "

reloadable= "true " >

</Context>

<Context path= "/web "

docBase= "webapps/web "

crossContext= "false "

debug= "0 "

reloadable= "true " >

</Context>

但现在总是报错

Error: 500

Location: /web/servlet/UploadFileServlet

Internal Servlet Error:

java.lang.NullPointerException

at java.lang.ClassLoader.resolveClass0(Native Method)

at java.lang.ClassLoader.resolveClass(ClassLoader.java:641)

at org.apache.tomcat.loader.AdaptiveClassLoader.loadClass(AdaptiveClassLoader.java:430)

at org.apache.tomcat.loader.AdaptiveServletLoader.loadClass(AdaptiveServletLoader.java:174)

at org.apache.tomcat.core.ServletWrapper.loadServlet(ServletWrapper.java:265)

at org.apache.tomcat.core.ServletWrapper.init(ServletWrapper.java:289)

at org.apache.tomcat.core.Handler.service(Handler.java:254)

at org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:372)

at org.apache.tomcat.core.ContextManager.internalService(ContextManager.java:797)

at org.apache.tomcat.core.ContextManager.service(ContextManager.java:743)

at org.apache.tomcat.service.http.HttpConnectionHandler.processConnection(HttpConnectionHandler.java:210)

at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:416)

at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:498)


[解决办法]
要寻求帮助,代码贴出来是阐述问题的最好的方法之一,lz你将servlet代码贴出来看看， 然后想怎么调用?
[解决办法]
WEB-INF目录下的web.xml配置路径配了么?