problem using "com.microsoft.jdbc.sqlserver.SQLServerDriver"

Hi.
the problem is probably just that your servlet code is not thread-safe.
Multiple threads are probably trying to use the same jdbc objects.
Define all your jdbc objects as method-level variables and you should
be OK...
Joe Weinstein at BEA
Simon Lee wrote:
> hi
> I am using "com.microsoft.jdbc.sqlserver.SQLServerDriver" driver to connect
> the SQL Server 2000.
> Everything is ok if there is one request to the SQL server.
> When there are more than one requests to the SQL server, exception was
> thrown
> I want to ask if that driver has some problems to handle multi-request.
> Thanks
> The expcetions are:
> java.sql.SQLException: [Microsoft][SQLServer 2000 Driver for JDBC]Object has
> been closed.
> at com.microsoft.jdbc.base.BaseExceptions.createExcep tion(Unknown
> Source)
> at com.microsoft.jdbc.base.BaseExceptions.getExceptio n(Unknown
> Source)
> at com.microsoft.jdbc.base.BaseResultSet.validateClos edState(Unknown
> Source)
> at
> com.microsoft.jdbc.base.BaseResultSet.commonFetchI nitialize(Unknown Source)
> at com.microsoft.jdbc.base.BaseResultSet.next(Unknown Source)
> at GetData.GetData.getColumn(GetData.java:192)
> at GetData.GetData.insert_fileInstance_table(GetData. java:1156)
> at RadicaPocketServer2.handleRequest(RadicaPocketServ er2.java:1056)
> at RadicaPocketServer2.doPost(RadicaPocketServer2.jav a:55)
> at javax.servlet.http.HttpServlet.service(HttpServlet .java:760)
> at javax.servlet.http.HttpServlet.service(HttpServlet .java:853)
> at
> org.apache.catalina.core.ApplicationFilterChain.in ternalDoFilter(Application
> FilterChain.java:247)
> at
> org.apache.catalina.core.ApplicationFilterChain.do Filter(ApplicationFilterCh
> ain.java:193)
> at
> org.apache.catalina.core.StandardWrapperValve.invo ke(StandardWrapperValve.ja
> va:256)
> at
> org.apache.catalina.core.StandardPipeline$Standard PipelineValveContext.invok
> eNext(StandardPipeline.java:643)
> at
> org.apache.catalina.core.StandardPipeline.invoke(S tandardPipeline.java:480)
> at
> org.apache.catalina.core.ContainerBase.invoke(Cont ainerBase.java:995)
> at
> org.apache.catalina.core.StandardContextValve.invo ke(StandardContextValve.ja
> va:191)
> at
> org.apache.catalina.core.StandardPipeline$Standard PipelineValveContext.invok
> eNext(StandardPipeline.java:643)
> at
> org.apache.catalina.core.StandardPipeline.invoke(S tandardPipeline.java:480)
> at
> org.apache.catalina.core.ContainerBase.invoke(Cont ainerBase.java:995)
> at
> org.apache.catalina.core.StandardContext.invoke(St andardContext.java:2415)
> at
> org.apache.catalina.core.StandardHostValve.invoke( StandardHostValve.java:180
> )
> at
> org.apache.catalina.core.StandardPipeline$Standard PipelineValveContext.invok
> eNext(StandardPipeline.java:643)
> at
> org.apache.catalina.valves.ErrorDispatcherValve.in voke(ErrorDispatcherValve.
> java:171)
> at
> org.apache.catalina.core.StandardPipeline$Standard PipelineValveContext.invok
> eNext(StandardPipeline.java:641)
> at
> org.apache.catalina.valves.ErrorReportValve.invoke (ErrorReportValve.java:172
> )
> at
> org.apache.catalina.core.StandardPipeline$Standard PipelineValveContext.invok
> eNext(StandardPipeline.java:641)
> at
> org.apache.catalina.valves.AccessLogValve.invoke(A ccessLogValve.java:509)
> at
> org.apache.catalina.core.StandardPipeline$Standard PipelineValveContext.invok
> eNext(StandardPipeline.java:641)
> at
> org.apache.catalina.core.StandardPipeline.invoke(S tandardPipeline.java:480)
> at
> org.apache.catalina.core.ContainerBase.invoke(Cont ainerBase.java:995)
> at
> org.apache.catalina.core.StandardEngineValve.invok e(StandardEngineValve.java
> :174)
> at
> org.apache.catalina.core.StandardPipeline$Standard PipelineValveContext.invok
> eNext(StandardPipeline.java:643)
> at
> org.apache.catalina.core.StandardPipeline.invoke(S tandardPipeline.java:480)
> at
> org.apache.catalina.core.ContainerBase.invoke(Cont ainerBase.java:995)
> at
> org.apache.ajp.tomcat4.Ajp13Processor.process(Ajp1 3Processor.java:466)
> at
> org.apache.ajp.tomcat4.Ajp13Processor.run(Ajp13Pro cessor.java:585)
> at java.lang.Thread.run(Thread.java:534)
>
Simon Lee wrote:

> Hello Joe
> Thanks for you suggestion, but I still have questions about it.
> My servlet is run in tomcat 5.0 and I know that tomcat help us to handle
> multiple threading problem
> Could you explain your idea to me more. Thank you
> Also, I have written a class called GetData.java which represent to connect
> and execute SQL statement.
> GetData is used by my servlet program to handle database connections
> Do you mean that I need to handle mutli-threading in GetData.java's
> functions
> Thank you very much
A servlet is a single class that can be run simultaneously by many
threads. Therefore you must make sure that no two threads are
using the same jdbc objects. If you have a single GetData class,
it must create, use, and close all the jdbc objects it is going to use
within each method it has. It shouldn't have permanent jdbc objects
that get re-used, unless you make your own thread-safe pooling code
that makes sure that no two threads use the same objects.
Otherwise you must make your servlet so that only one thread
can run it at a time.
Joe Weinstein at BEA
> Simon Lee
> "Joe Weinstein" <joeNOSPAM@.bea.com> ? news:407FFE48.30900@.bea.com ?...
>
> connect
>
> has
>
> com.microsoft.jdbc.base.BaseExceptions.createExcep tion(Unknown
>
> com.microsoft.jdbc.base.BaseResultSet.validateClos edState(Unknown
>
> Source)
>
> RadicaPocketServer2.handleRequest(RadicaPocketServ er2.java:1056)
>
> org.apache.catalina.core.ApplicationFilterChain.in ternalDoFilter(Application
>
> org.apache.catalina.core.ApplicationFilterChain.do Filter(ApplicationFilterCh
>
> org.apache.catalina.core.StandardWrapperValve.invo ke(StandardWrapperValve.ja
>
> org.apache.catalina.core.StandardPipeline$Standard PipelineValveContext.invok
>
> org.apache.catalina.core.StandardPipeline.invoke(S tandardPipeline.java:480)
>
> org.apache.catalina.core.StandardContextValve.invo ke(StandardContextValve.ja
>
> org.apache.catalina.core.StandardPipeline$Standard PipelineValveContext.invok
>
> org.apache.catalina.core.StandardPipeline.invoke(S tandardPipeline.java:480)
>
> org.apache.catalina.core.StandardContext.invoke(St andardContext.java:2415)
>
> org.apache.catalina.core.StandardHostValve.invoke( StandardHostValve.java:180
>
> org.apache.catalina.core.StandardPipeline$Standard PipelineValveContext.invok
>
> org.apache.catalina.valves.ErrorDispatcherValve.in voke(ErrorDispatcherValve.
>
> org.apache.catalina.core.StandardPipeline$Standard PipelineValveContext.invok
>
> org.apache.catalina.valves.ErrorReportValve.invoke (ErrorReportValve.java:172
>
> org.apache.catalina.core.StandardPipeline$Standard PipelineValveContext.invok
>
> org.apache.catalina.valves.AccessLogValve.invoke(A ccessLogValve.java:509)
>
> org.apache.catalina.core.StandardPipeline$Standard PipelineValveContext.invok
>
> org.apache.catalina.core.StandardPipeline.invoke(S tandardPipeline.java:480)
>
> org.apache.catalina.core.StandardEngineValve.invok e(StandardEngineValve.java
>
> org.apache.catalina.core.StandardPipeline$Standard PipelineValveContext.invok
>
> org.apache.catalina.core.StandardPipeline.invoke(S tandardPipeline.java:480)
>
>