webwork+hibernate的一个异常!!拜求答案

(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.StandardContextValve.invoke(StandardContextValve.java:178)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:825)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:731)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:526)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
at java.lang.Thread.run(Thread.java:595)
2004-12-30 01:20:10,500 WARN net.sf.hibernate.util.JDBCExceptionReporter - SQL Error: 17002, SQLState: null
2004-12-30 01:20:10,500 ERROR net.sf.hibernate.util.JDBCExceptionReporter - Io 异常: Socket closed
2004-12-30 01:20:10,500 DEBUG net.sf.hibernate.impl.BatcherImpl - done closing: 0 open PreparedStatements, -1 open ResultSets
2004-12-30 01:20:10,500 DEBUG net.sf.hibernate.impl.BatcherImpl - closing statement
2004-12-30 01:20:10,515 DEBUG net.sf.hibernate.util.JDBCExceptionReporter - Could not execute query
java.sql.SQLException: Io 异常: Socket closed
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:158)
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:206)
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:382)
at oracle.jdbc.driver.T4CPreparedStatement.execute_for_describe(T4CPreparedStatement.java:521)
at oracle.jdbc.driver.OracleStatement.execute_maybe_describe(OracleStatement.java:979)
at oracle.jdbc.driver.T4CPreparedStatement.execute_maybe_describe(T4CPreparedStatement.java:552)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1096)
at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:3018)
at oracle.jdbc.driver.OraclePreparedStatement.executeQuery(OraclePreparedStatement.java:3059)
at org.apache.commons.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:92)
at net.sf.hibernate.impl.BatcherImpl.getResultSet(BatcherImpl.java:88)
at net.sf.hibernate.loader.Loader.getResultSet(Loader.java:875)
at net.sf.hibernate.hql.QueryTranslator.iterate(QueryTranslator.java:868)
at net.sf.hibernate.impl.SessionImpl.iterate(SessionImpl.java:1618)
at net.sf.hibernate.impl.SessionImpl.iterate(SessionImpl.java:1591)
at com.sfexpress.server.persistence.hibernate.EntityDAOHibernateImpl.getObjects(EntityDAOHibernateImpl.java:122)
at com.sfexpress.server.facade.impl.BaseServiceImpl.getObjects(BaseServiceImpl.java:58)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)