使用Tomcat服务器运行程序时，出现下面的问题：

java.lang.NoClassDefFoundError: org/dom4j/DocumentException
 at org.apache.jsp.GetDSLists_jsp._jspService(GetDSLists_jsp.java:47)
 at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
 at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331)
 at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
 at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
 at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
 at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:174)
 at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
 at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
 at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
 at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:151)
 at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:874)
 at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
 at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
 at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
 at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
 at java.lang.Thread.run(Unknown Source)

解决的办法：把 dom4j.jar 复制到 tomcat/shared/lib 目录下面