一个Hibernate在Tomcat5.5下的错误信息```

Question

Last   packet   sent   to   the   server   was   0   ms   ago.
org.hibernate.exception.JDBCConnectionException:   could   not   execute   query
at   org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:74)
at   org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
at   org.hibernate.loader.Loader.doList(Loader.java:2148)
at   org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2029)
at   org.hibernate.loader.Loader.list(Loader.java:2024)
at   org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:375)
at   org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:308)
at   org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:153)
at   org.hibernate.impl.SessionImpl.list(SessionImpl.java:1106)
at   org.hibernate.impl.QueryImpl.list(QueryImpl.java:79)
at   cn.pior.placardDAO.placardDAO.getSkins(placardDAO.java:238)
at   cn.pior.placardSystem.Home.getSkinsList(Home.java:46)
at   cn.pior.placardSystem.Home. <init> (Home.java:26)
at   sun.reflect.GeneratedConstructorAccessor60.newInstance(Unknown   Source)
at   sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown   Source)
at   java.lang.reflect.Constructor.newInstance(Unknown   Source)
at   java.lang.Class.newInstance0(Unknown   Source)
at   java.lang.Class.newInstance(Unknown   Source)
at   com.opensymphony.xwork2.ObjectFactory.buildBean(ObjectFactory.java:123)
at   com.opensymphony.xwork2.ObjectFactory.buildBean(ObjectFactory.java:154)
at   com.opensymphony.xwork2.ObjectFactory.buildBean(ObjectFactory.java:143)
at   com.opensymphony.xwork2.ObjectFactory.buildAction(ObjectFactory.java:113)
at   com.opensymphony.xwork2.DefaultActionInvocation.createAction(DefaultActionInvocation.java:275)
at   com.opensymphony.xwork2.DefaultActionInvocation.init(DefaultActionInvocation.java:365)
at   com.opensymphony.xwork2.DefaultActionInvocation.access$000(DefaultActionInvocation.java:38)
at   com.opensymphony.xwork2.DefaultActionInvocation$1.doProfiling(DefaultActionInvocation.java:83)
at   com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
at   com.opensymphony.xwork2.DefaultActionInvocation. <init> (DefaultActionInvocation.java:74)
at   com.opensymphony.xwork2.DefaultActionProxy.prepare(DefaultActionProxy.java:189)
at   org.apache.struts2.impl.StrutsActionProxyFactory.createActionProxy(StrutsActionProxyFactory.java:41)
at   org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:494)
at   org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:419)
at   org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at   org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at   org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at   org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
at   org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
at   org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
at   org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
at   org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
at   org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:868)
at   org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:663)
at   org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
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(Unknown   Source)
Caused   by:   com.mysql.jdbc.CommunicationsException:   Communications   link   failure   due   to   underlying   exception:  **   BEGIN   NESTED  EXCEPTION   **  java.net.SocketException
MESSAGE:   Software   caused   connection   abort:   socket   write   errorSTACKTRACE:java.net.SocketException:   Software   caused   connection   abort:   socket   write   error
at   java.net.SocketOutputStream.socketWrite0(Native   Method)
at   java.net.SocketOutputStream.socketWrite(Unknown   Source)
at   java.net.SocketOutputStream.write(Unknown   Source)
at   java.io.BufferedOutputStream.flushBuffer(Unknown   Source)
at   java.io.BufferedOutputStream.flush(Unknown   Source)
at   com.mysql.jdbc.MysqlIO.send(MysqlIO.java:2739)
at   com.mysql.jdbc.MysqlIO.send(MysqlIO.java:2650)
at   com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1581)
at   com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1695)
at   com.mysql.jdbc.Connection.execSQL(Connection.java:3004)
at   com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1128)
at   com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1222)
at   org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:139)
at   org.hibernate.loader.Loader.getResultSet(Loader.java:1669)
at   org.hibernate.loader.Loader.doQuery(Loader.java:662)
at   org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:224)
at   org.hibernate.loader.Loader.doList(Loader.java:2145)
at   org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2029)
at   org.hibernate.loader.Loader.list(Loader.java:2024)
at   org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:375)
at   org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:308)
at   org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:153)
at   org.hibernate.impl.SessionImpl.list(SessionImpl.java:1106)
at   org.hibernate.impl.QueryImpl.list(QueryImpl.java:79)
at   cn.pior.placardDAO.placardDAO.getSkins(placardDAO.java:238)
at   cn.pior.placardSystem.Home.getSkinsList(Home.java:46)
at   cn.pior.placardSystem.Home. <init> (Home.java:26)
at   sun.reflect.GeneratedConstructorAccessor60.newInstance(Unknown   Source)
at   sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown   Source)
at   java.lang.reflect.Constructor.newInstance(Unknown   Source)
at   java.lang.Class.newInstance0(Unknown   Source)
at   java.lang.Class.newInstance(Unknown   Source)
at   com.opensymphony.xwork2.ObjectFactory.buildBean(ObjectFactory.java:123)
at   com.opensymphony.xwork2.ObjectFactory.buildBean(ObjectFactory.java:154)
at   com.opensymphony.xwork2.ObjectFactory.buildBean(ObjectFactory.java:143)
at   com.opensymphony.xwork2.ObjectFactory.buildAction(ObjectFactory.java:113)
at   com.opensymphony.xwork2.DefaultActionInvocation.createAction(DefaultActionInvocation.java:275)
at   com.opensymphony.xwork2.DefaultActionInvocation.init(DefaultActionInvocation.java:365)
at   com.opensymphony.xwork2.DefaultActionInvocation.access$000(DefaultActionInvocation.java:38)
at   com.opensymphony.xwork2.DefaultActionInvocation$1.doProfiling(DefaultActionInvocation.java:83)
at   com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
at   com.opensymphony.xwork2.DefaultActionInvocation. <init> (DefaultActionInvocation.java:74)
at   com.opensymphony.xwork2.DefaultActionProxy.prepare(DefaultActionProxy.java:189)
at   org.apache.struts2.impl.StrutsActionProxyFactory.createActionProxy(StrutsActionProxyFactory.java:41)
at   org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:494)
at   org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:419)
at   org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)**   END   NESTED   EXCEPTION   **

Answer 1

ERROR   -   Servlet.service()   for   servlet   default   threw   exception
Unable   to   instantiate   Action,   cn.pior.placardSystem.Home,     defined   for   'Home'   in   namespace   '/'null   -   action   -  file:/D:/Apache%20Software%20Foundation/Tomcat%205.5/webapps/ROOT/WEB-INF/classes/struts.xml:12:58
at   com.opensymphony.xwork2.DefaultActionInvocation.createAction(DefaultActionInvocation.java:294)
at   com.opensymphony.xwork2.DefaultActionInvocation.init(DefaultActionInvocation.java:365)
at   com.opensymphony.xwork2.DefaultActionInvocation.access$000(DefaultActionInvocation.java:38)
at   com.opensymphony.xwork2.DefaultActionInvocation$1.doProfiling(DefaultActionInvocation.java:83)
at   com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
at   com.opensymphony.xwork2.DefaultActionInvocation. <init> (DefaultActionInvocation.java:74)
at   com.opensymphony.xwork2.DefaultActionProxy.prepare(DefaultActionProxy.java:189)
at   org.apache.struts2.impl.StrutsActionProxyFactory.createActionProxy(StrutsActionProxyFactory.java:41)
at   org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:494)
at   org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:419)
at   org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at   org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at   org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at   org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
at   org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
at   org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
at   org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
at   org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
at   org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:868)
at   org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:663)
at   org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
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(Unknown   Source)
Caused   by:   java.lang.NullPointerException
at   cn.pior.placardSystem.Home.getSkinsList(Home.java:48)
at   cn.pior.placardSystem.Home. <init> (Home.java:26)
at   sun.reflect.GeneratedConstructorAccessor60.newInstance(Unknown   Source)
at   sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown   Source)
at   java.lang.reflect.Constructor.newInstance(Unknown   Source)
at   java.lang.Class.newInstance0(Unknown   Source)
at   java.lang.Class.newInstance(Unknown   Source)
at   com.opensymphony.xwork2.ObjectFactory.buildBean(ObjectFactory.java:123)
at   com.opensymphony.xwork2.ObjectFactory.buildBean(ObjectFactory.java:154)
at   com.opensymphony.xwork2.ObjectFactory.buildBean(ObjectFactory.java:143)
at   com.opensymphony.xwork2.ObjectFactory.buildAction(ObjectFactory.java:113)
at   com.opensymphony.xwork2.DefaultActionInvocation.createAction(DefaultActionInvocation.java:275)
...   23   more

Answer 2

整个系统一开始用没有问题```log里也没有错误``用上两三天就不行了``