调试JSP出现两个不明错误，请高手指教！！！

qdxby

HTTP Status 500 -

--------------------------------------------------------------------------------

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException
        at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:254)
        at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:295)
        at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:241)
        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 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.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:2422)
        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:163)
        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:199)
        at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:82
        at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:700)
        at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:584)
        at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
        at java.lang.Thread.run(Thread.java:534)


root cause

java.lang.NullPointerException
        at mybean.DbBean.queryData(DbBean.java:10
        at org.apache.jsp.pick_jsp._jspService(pick_jsp.java:94)
        at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:137)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
        at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:210)
        at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:295)
        at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:241)
        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 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.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:2422)
        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:163)
        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:199)
        at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:82
        at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:700)
        at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:584)
        at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
        at java.lang.Thread.run(Thread.java:534)


第2个错误很明显是空指针，第一个错误到底是什么原因呢？

猫小

500 Internal Server Error
An internal server error has caused the server to abort your request. This is an error condition that may also indicate a misconfiguration with the web server. However, the most common reason for 500 server errors is when you try to execute a script that has syntax errors.

dennis2

root cause

java.lang.NullPointerException
at mybean.DbBean.queryData(DbBean.java:10  <<=== 错误在这里

dennis2

把你的 DbBean.java 的第 108 行贴上来。

express

可能是个没有初始化的conn变量。