請教nullpointerexception

flutist-flute發表於2006-02-14
NullException
我練習一jsp查詢（分頁顯示），當選擇下拉選單檢視相應頁面資訊的時候出現了NullPointerException，特想詳細請教有關此異常的資訊。謝謝！

D:\Borland\JBuilder2005\jdk1.4\bin\javaw -classpath "D:\Borland\JBuilder2005\thirdparty\jakarta-tomcat-5.0.27\bin\bootstrap.jar;D:\66備份 在 192.168.100.65 上\resin-3.0.8\resin-3.0.8\class12.zip;D:\Borland\JBuilder2005\jdk1.4\lib\tools.jar" "-Dcatalina.home=D:/Borland/JBuilder2005/thirdparty/jakarta-tomcat-5.0.27" org.apache.catalina.startup.Bootstrap -config D:\study\jsp\NewTest42\Tomcat\conf\server8080.xml start
2006-2-13 13:08:57 org.apache.coyote.http11.Http11Protocol init
資訊: Initializing Coyote HTTP/1.1 on http-8080
2006-2-13 13:08:57 org.apache.catalina.startup.Catalina load
資訊: Initialization processed in 3906 ms
2006-2-13 13:08:57 org.apache.catalina.core.StandardService start
資訊: Starting service Catalina
2006-2-13 13:08:57 org.apache.catalina.core.StandardEngine start
資訊: Starting Servlet Engine: Apache Tomcat/5.0.27
2006-2-13 13:08:57 org.apache.catalina.core.StandardHost start
資訊: XML validation disabled
2006-2-13 13:08:59 org.apache.catalina.core.StandardHost getDeployer
資訊: Create Host deployer for direct deployment ( non-jmx )
2006-2-13 13:08:59 org.apache.coyote.http11.Http11Protocol start
資訊: Starting Coyote HTTP/1.1 on http-8080
2006-2-13 13:08:59 org.apache.catalina.startup.Catalina start
資訊: Server startup in 2484 ms
StandardWrapperValve[debugjsp]: Servlet.service() for servlet debugjsp threw exception
java.lang.NullPointerException
java.lang.NullPointerException
at org.apache.jsp.pagedata_jsp._jspService(pagedata_jsp.java:106)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:324)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:152)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
at java.lang.Thread.run(Thread.java:534)
2006-2-13 13:09:31 org.apache.coyote.http11.Http11Protocol pause
資訊: Pausing Coyote HTTP/1.1 on http-8080
2006-2-13 13:09:32 org.apache.catalina.core.StandardService stop
資訊: Stopping service Catalina
2006-2-13 13:09:32 org.apache.catalina.core.StandardHostDeployer remove
資訊: Removing web application at context path /WebModule1
2006-2-13 13:09:32 org.apache.coyote.http11.Http11Protocol destroy
資訊: Stopping Coyote HTTP/1.1 on http-8080

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