（急！！！）新手菜鸟提问，关于在tomcat下运行servlet的问题，请各位大虾帮忙！！

Question

接上面…………
root cause java.lang.NoClassDefFoundError: DBConnectionManager$DBConnectionPool
at DBConnectionManager.createPools(DBConnectionManager.java:154)
at DBConnectionManager.init(DBConnectionManager.java:194)
at DBConnectionManager.(DBConnectionManager.java:38)
at DBConnectionManager.getInstance(DBConnectionManager.java:27)
at TestServlet.init(TestServlet.java:10)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:935)
at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:668)
at org.apache.catalina.servlets.InvokerServlet.serveRequest(InvokerServlet.java:416)
at org.apache.catalina.servlets.InvokerServlet.doGet(InvokerServlet.java:180)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:247)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
at filters.ExampleFilter.doFilter(ExampleFilter.java:149)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:213)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
at filters.ExampleFilter.doFilter(ExampleFilter.java:149)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:213)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:256)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:494)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2415)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:180)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:171)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:172)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:174)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.coyote.tomcat4.CoyoteAdapter.service(CoyoteAdapter.java:223)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:594)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:392)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:565)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:619)
at java.lang.Thread.run(Thread.java:534)小弟是新手菜鸟，还请各位大虾帮我解决这个问题，不甚感谢！！！

Answer 1

NoClassDefFoundError
classpath的问题啦，看看你的驱动有没有安装好

Answer 2

kingofhawks() 
 我已经安装了sqlserver的驱动，并且在编译的时候把msbase.jar,msutil.jar,mssqlserver.jar以及servlet.jar四个包都导入了，在编译的时候没有出现问题！我不知道上面我写的那个db.properties文件是不是正确。
 请各位能帮我解决这个servlet的运行问题！！
 我愿意将仅有的100分都奉送！！谢谢！！
 小弟的QQ是：405366443。愿意和各位交个朋友！！

Answer 3

首先,你确认在你机器上别的servlet都能正常运行,那样你的环境就没有问题.
其次,建议你调试一下你的servlet,在数据库操作的每个地方都加上log信息,你如果没有出exception  的话，基本上可以肯定是包和数据库设置问题,
把你的代码贴上来看看呢
呵呵，我用的tomcat 5.0.28,我觉得那个还算好用的了