继续收到org.hibernate.exception.JDBCConnectionException：无法执行查询 [英] Keep getting org.hibernate.exception.JDBCConnectionException: could not execute query

问题描述

我有一个J2EE应用程序，它使用JSP页面作为前端，Struts2作为控制器。我也使用Hibernate将我的对象映射到MySql DB中。当我在服务器上部署应用程序时它工作正常，但在无法预测的时间段（如1或2天）后，无论我使用hibernate查询，我都会收到此错误：

  org.hibernate.exception.JDBCConnectionException：无法执行查询
  

让它更有趣的事实是，当这种情况发生时，并不是100％的查询最终会导致这种异常！有时它们中的一些被正确执行。

一个错误发生的代码片段：

  public synchronized static Player getPlayerByID（String playerID）throws NoSuchPlayer {
 
 Session session = HibernateUtil.getSessionFactory（）。getCurrentSession（）; 
 session.beginTransaction（）; 
 Player player =（Player）session.createQuery（
from Player as player where player.loginName ='+ playerID 
 +'）.uniqueResult（）; // THE ERROR HAPPENS HERE 
 session.getTransaction（）。commit（）; 
 
 if（player == null）
 throw new NoSuchPlayer（）; 
 
返回玩家; 
} 
  

这是相应的堆栈跟踪：

'pre> org.hibernate.exception.JDBCConnectionException：在org.hibernate.exception.SQLStateConverter.convert（SQLStateConverter.java:99）$无法执行查询
b $ b在org.hibernate.exception.JDBCExceptionHelper.convert（JDBCExceptionHelper.java:66）
在org.hibernate.loader.Loader.doList（Loader.java:2297）
在org.hibernate。 loader.Loader.listIgnoreQueryCache（Loader.java:2172）
在org.hibernate.loader.Loader.list（Loader.java:2167）
在org.hibernate.loader.hql.QueryLoader.list（ QueryLoader.java:448）
在org.hibernate.hql.ast.QueryTranslatorImpl.list（QueryTranslatorImpl.java:363）
在org.hibernate.engine.query.HQLQueryPlan.performList（HQLQueryPlan.java：
at org.hibernate.impl.SessionImpl.list（SessionImpl.java:1258）
at org.hibernate.impl.QueryImpl.list（QueryImpl.java： 102）
at org.hibernate.impl.AbstractQueryImpl.uniqueResult（AbstractQueryImpl.java:859）
at com.hposg.domain.HPOSG.getPlayerByID（HPOSG.java:117）
at com .hposg.login.UserSession.getPlayerById（UserSession.java:39）
at com.hposg.controller.struts.BuyAction.execute（BuyAction.java:74）
at sun.reflect.GeneratedMethodAccessor1098.invoke （来源不明）美元，sun.reflect.DelegatingMethodAccessorImpl.invoke（DelegatingMethodAccessorImpl.java:43）b
$ b。在java.lang.reflect.Method.invoke（Method.java:616）
。在COM .opensymphony.xwork2.DefaultActionInvocation.invokeAction（DefaultActionInvocation.java:441）
at com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly（DefaultActionInvocation.java:280）
at com.opensymphony.xwork2.DefaultActionInvocation.invoke （DefaultActionInvocation.java:243）
at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept（Defa ultWorkflowInterceptor.java:165）美元，com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept（MethodFilterInterceptor.java:87 B $ B）
在com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）在com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept（ValidationInterceptor.java:252）

在org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept（AnnotationValidationInterceptor.java:68）
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept（MethodFilterInterceptor.java:87）
at com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）
at com.opensymphony .xwork2.interceptor.ConversionErrorInterceptor.intercept（ConversionErrorInterceptor.java:122）
at com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）
at com.opensymph ony.xwork2.interceptor.ParametersInterceptor.doIntercept（ParametersInterceptor.java:195）
处com.opensymphony.xwork2 com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept（MethodFilterInterceptor.java:87）
。 DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）
在com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept（ParametersInterceptor.java:195）
在com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept（ MethodFilterInterceptor.java:87）美元，com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237 b $ b）
在com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept（StaticParametersInterceptor.java:179）
at com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）
at org.apache.struts2.interceptor.MultiselectInterceptor.intercept（MultiselectInterceptor.java:75）在com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）

在org.apache.struts2.interceptor.CheckboxInterceptor.intercept（CheckboxInterceptor.java:94）
。在COM .opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）
at org.apache.struts2.interceptor.FileUploadInterceptor.intercept（FileUploadInterceptor.java:235）
at com.opensymphony.xwork2.DefaultActionInvocation .invoke（DefaultActionInvocation.java:237）
at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept（ModelDrivenInterceptor.java:89）
at com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java ：237）
at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept（ScopedModelDrivenInterceptor.java:130）
at com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）
在org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept（DebuggingInterceptor.java:267）
在com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）
在com.opensymphony .xwork2.interceptor.ChainingInterceptor.intercept（ChainingInterceptor.java:126）
at com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）
at com.opensymphony.xwork2.interceptor.PrepareInterceptor .doIntercept（PrepareInterceptor.java:138）
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept（MethodFilterInterceptor.java:87）
at com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java ：237）
at com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept（I18nInterceptor.java:165）
at com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）
在org.apach e.struts2.interceptor.ServletConfigInterceptor.intercept（ServletConfigInterceptor.java:164）
at com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）
at com.opensymphony.xwork2.interceptor。 AliasInterceptor.intercept（AliasInterceptor.java:179）
at com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）
at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept（ExceptionMappingInterceptor。的java：176）$在com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237 b $ b）
。在org.apache.struts2.impl.StrutsActionProxy.execute（StrutsActionProxy.java:52）
at org.apache.struts2.dispatcher.Dispatcher.serviceAction（Dispatcher.java:488）
at org.apache.struts2.dispatcher.FilterDispatcher.doFilter（FilterDispatcher.java:395）
at org .apache.catalina.core.ApplicationFilterChain.internalDoF ilter（ApplicationFilterChain.java:235）
at org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:206）
at org.apache.catalina.core.StandardWrapperValve.invoke（StandardWrapperValve。的java：233）$在org.apache.catalina.core.StandardContextValve.invoke（StandardContextValve.java:191 b $ b）
。在org.apache.catalina.core.StandardHostValve.invoke（StandardHostValve.java:127）
at org.apache.catalina.valves.ErrorReportValve.invoke（ErrorReportValve.java:102）
at org.apache.catalina.core.StandardEngineValve.invoke（StandardEngineValve.java:109）
在org.apache.catalina.connector.CoyoteAdapter.service（CoyoteAdapter.java:298）
at org.apache.coyote.http11.Http11Processor.process（Http11Processor.java:857）
at org.apache .coyote.http11.Http11Protocol $ Http11ConnectionHandler.process（Http11Protocol.java:588）
在org.apache.tomcat.util.net.JIoEndpoint $ Worker.run（JIoEndp oint.java:489）
在java.lang.Thread.run（Thread.java:636）
引起：com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException：连接关闭后不允许任何操作。由于潜在的异常/错误，连接被隐式关闭：


** BEGIN NESTED EXCEPTION **

com.mysql.jdbc.exceptions.jdbc4.CommunicationsException
MESSAGE：通信链路故障

发送到服务器的最后一个数据包是0 ms前。

STACKTRACE：

com.mysql.jdbc.exceptions.jdbc4.CommunicationsException：通信链路故障

发送到服务器的最后一个数据包为0 ms前。
at sun.reflect.NativeConstructorAccessorImpl.newInstance0（Native Method）
at sun.reflect.NativeConstructorAccessorImpl.newInstance（NativeConstructorAccessorImpl.java:57）
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance（DelegatingConstructorAccessorImpl。 java：45）
at java.lang.reflect.Constructor.newInstance（Constructor.java:532）
at com.mysql.jdbc.Util.handleNewInstance（Util.java:353）
at com.mysql.jdbc.SQLError.createCommunicationsException（SQLError.java:1074）
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket（MysqlIO.java:2583）
at com.mysql.jdbc.MysqlIO .checkErrorPacket（MysqlIO.java:2871）
在com.mysql.jdbc.MysqlIO.sendCommand（MysqlIO.java:1601）在com.mysql.jdbc.MysqlIO.sqlQueryDirect
（MysqlIO.java:1710 ）
at com.mysql.jdbc.Connection.execSQL（Connection.java:2436）
at com.mysql.jdbc.PreparedStatement.executeInternal（PreparedStatement.java:1402）
at com。 mysql.jdbc.PreparedS tatement.executeQuery（PreparedStatement.java:1556）
在org.hibernate.jdbc.AbstractBatcher.getResultSet（AbstractBatcher.java:208）
在org.hibernate.loader.Loader.getResultSet（Loader.java： 1849）
在org.hibernate.loader.Loader.doQuery（Loader.java:718）
在org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections（Loader.java:270）
。在组织.hibernate.loader.Loader.doList（Loader.java:2294）
在org.hibernate.loader.Loader.listIgnoreQueryCache（Loader.java:2172）
在org.hibernate.loader.Loader.list （Loader.java:2167）
在org.hibernate.loader.hql.QueryLoader.list（QueryLoader.java:448）
在org.hibernate.hql.ast.QueryTranslatorImpl.list（QueryTranslatorImpl.java ：363）
at org.hibernate.engine.query.HQLQueryPlan.performList（HQLQueryPlan.java:196）
at org.hibernate.impl.SessionImpl.list（SessionImpl.java:1258）
位于org.hibernate.impl.QueryImpl.list（QueryImpl.java:102）
位于com.hposg.domain.HPOSG。 getGameList（HPOSG.java:222）
at com.hposg.controller.struts.GamesLoadActionAjax.execute（GamesLoadActionAjax.java:23）
at sun.reflect.GeneratedMethodAccessor1047.invoke（Unknown Source）
at sun.reflect.DelegatingMethodAccessorImpl.invoke（DelegatingMethodAccessorImpl.java:43）
at java.lang.reflect.Method.invoke（Method.java:616）
at com.opensymphony.xwork2.DefaultActionInvocation。 invokeAction（DefaultActionInvocation.java:441）
at com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly（DefaultActionInvocation.java:280）
at com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:243）
at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept（DefaultWorkflowInterceptor.java:165）
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept（MethodFilterInterceptor.java:87）
在com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInv
at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept（ValidationInterceptor.java:252）
at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept（AnnotationValidationInterceptor。的java：在com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept（MethodFilterInterceptor.java:87 68）
）
。在com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）
at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept（ConversionErrorInterceptor.java:122）
at com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）
at com.opensymphony .xwork2.interceptor.ParametersInterceptor.doIntercept（ParametersInterceptor.java:195）
在com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept（MethodFilterInterceptor.java:87）
在com.opensymphony.xwork2.DefaultActionInvocation .inv oke（DefaultActionInvocation.java:237）
at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept（ParametersInterceptor.java:195）
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept（MethodFilterInterceptor。的java：在com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237 87）
）
。在com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept（StaticParametersInterceptor.java:179）
at com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）
at org.apache.struts2.interceptor.MultiselectInterceptor.intercept（MultiselectInterceptor.java:75）
at com.opensymphony .xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）
at org.apache.struts2.interceptor.CheckboxInterceptor.intercept（CheckboxInterceptor.java:94）
at com.opensymphony.xwork2.DefaultActionInvocation.invoke （DefaultActionInvocation.java： 237）
在org.apache.struts2.interceptor.FileUploadInterceptor.intercept（FileUploadInterceptor.java:235）
在com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）
在com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept（ModelDrivenInterceptor.java:89）
at com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）
at com.opensymphony.xwork2 .interceptor.ScopedModelDrivenInterceptor.intercept（ScopedModelDrivenInterceptor.java:130）
at com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）
at org.apache.struts2.interceptor.debugging.DebuggingInterceptor .intercept（DebuggingInterceptor.java:267）
在com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）
在com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept（ChainingInterceptor.java ：126）
在com.opensy mphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）
处com.opensymphony.xwork2.interceptor com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept（PrepareInterceptor.java:138）
。 MethodFilterInterceptor.intercept（MethodFilterInterceptor.java:87）
at com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）
at com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept（I18nInterceptor。 java：165）
at com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）
at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept（ServletConfigInterceptor.java:164）
at com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）
at com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept（AliasInterceptor.java:179）
at com.opensymphony .xwork2.DefaultActionInvocation.invoke（DEFAULTACTION Invocation.java:237）
at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept（ExceptionMappingInterceptor.java:176）
at com.opensymphony.xwork2.DefaultActionInvocation.invoke（DefaultActionInvocation.java:237）在org.apache.struts2.impl.StrutsActionProxy.execute（StrutsActionProxy.java:52）

在org.apache.struts2.dispatcher.Dispatcher.serviceAction（Dispatcher.java:488）
在org.apache.struts2.dispatcher.FilterDispatcher.doFilter（FilterDispatcher.java:395）
在org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:235）
在org.apache .catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:206）
at org.apache.catalina.core.StandardWrapperValve.invoke（StandardWrapperValve.java:233）
at org.apache.catalina.core .StandardContextValve.invoke（StandardContextValve.java:191）
at org.apache.catalina.core.StandardHostValve.invoke（StandardHostValv e.java:127）
在org.apache.catalina.core.StandardEngineValve.invoke（StandardEngineValve.java：org.apache.catalina.valves.ErrorReportValve.invoke（ErrorReportValve.java:102）
在org.apache.catalina.connector.CoyoteAdapter.service（CoyoteAdapter.java:298 109）
）
。在org.apache.coyote.http11.Http11Processor.process（Http11Processor.java:857）
at org.apache.coyote.http11.Http11Protocol $ Http11ConnectionHandler.process（Http11Protocol.java:588）
at org.apache.tomcat.util.net.JIoEndpoint $ Worker.run（JIoEndpoint.java:489）
at java.lang.Thread.run（Thread.java:636）
引起：java.io.EOFException
在com.mysql.jdbc.MysqlIO.readFully（MysqlIO.java： 1958）
在com.mysql.jdbc.MysqlIO.reuseAndReadPacket（MysqlIO.java:2372）
... 83 more


**结束嵌套异常* *


at sun.reflect.GeneratedConstructorAccessor139.newInstance（Unknown Source）
at sun.reflect.DelegatingConstructorAccess orImpl.newInstance（DelegatingConstructorAccessorImpl.java:45）
在java.lang.reflect.Constructor.newInstance（Constructor.java:532）
在com.mysql.jdbc.Util.handleNewInstance（Util.java：在com.mysql.jdbc.Util.getInstance（Util.java:336 353）
）
在com.mysql.jdbc.SQLError.createSQLException（SQLError.java:985）
。在COM .mysql.jdbc.SQLError.createSQLException（SQLError.java:957）
在com.mysql.jdbc.SQLError.createSQLException（SQLError.java:927）
在com.mysql.jdbc.Connection.checkClosed （Connection.java:1103）
at com.mysql.jdbc.Connection.prepareStatement（Connection.java:3865）
at com.mysql.jdbc.Connection.prepareStatement（Connection.java:3831）
。在org.hibernate.jdbc.AbstractBatcher.getPreparedStatement（AbstractBatcher.java:534）
处org.hibernate作为org.hibernate.jdbc.AbstractBatcher.getPreparedStatement（AbstractBatcher.java:452）
。 jdbc.AbstractBatcher.prepareQueryStatement（AbstractBatcher.java:161）
在org.hibernate.loader.Loader.prepareQueryStatement（Loader.java:1596）
在org.hibernate.loader.Loader.doQuery（Loader.java:717）
在org.hibernate.loader.Loader .doQueryAndInitializeNonLazyCollections（Loader.java:270）在org.hibernate.loader.Loader.doList（Loader.java:2294）

... 74更
'


最后这是我的hibernate配置文件：

 <？xml version ='1.0'encoding ='utf-8'？> 
  

 <！ - 数据库连接设置 - > 
< property name =connection.driver_class> com.mysql.jdbc.Driver< / property> 
< property name =hibernate.connection.url> 
 jdbc：mysql：// localhost / hposg？characterEncoding = UTF-8 
< / property> 
< property name =connection.username> root< / property> 
< property name =connection.password>< / property> 
 
 <！ -  JDBC连接池（使用内置） - > 
< property name =connection.pool_size> 1< / property> 
 
 <！ - 将所有执行的SQL回复到stdout  - > 
< property name =show_sql> true< / property> 
 
 <！ -   -  SQL方言 - > 
< property name =dialect> org.hibernate.dialect.MySQLDialect< / property> 
 
 <！ - 启用Hibernate的自动会话上下文管理 - > 
< property name =current_session_context_class>线程< / property> 
 
 <！ - 禁用二级缓存 - > 
< property name =cache.provider_class> org.hibernate.cache.NoCacheProvider< / property> 
 
 <！ - 在启动时删除并重新创建数据库模式 - > 
< property name =hbm2ddl.auto>更新< / property> 
 
 <！ - 映射文件 - > 
 
< mapping resource =com / hposg / hibernate / resources / Player.hbm.xml/> 
< mapping resource =com / hposg / hibernate / resources / Game.hbm.xml/> 
< mapping resource =com / hposg / hibernate / resources / Portfolio.hbm.xml/> 
< mapping resource =com / hposg / hibernate / resources / Purchase.hbm.xml/> 
< mapping resource =com / hposg / hibernate / resources / Sale.hbm.xml/> 
< mapping resource =com / hposg / hibernate / resources / Message.hbm.xml/> 
< mapping resource =com / hposg / hibernate / resources / Admin.hbm.xml/> 
< mapping resource =com / hposg / hibernate / resources / News.hbm.xml/> 
< mapping resource =com / hposg / hibernate / resources / Invitation.hbm.xml/> 
< mapping resource =com / hposg / hibernate / resources / CustomGameCreationRequest.hbm.xml/> 
< mapping resource =com / hposg / hibernate / resources / Alert.hbm.xml/> 
< mapping resource =com / hposg / hibernate / resources / AlertLimits.hbm.xml/> 
< mapping resource =com / hposg / hibernate / resources / StockIndex.hbm.xml/> 
< mapping resource =com / hposg / hibernate / resources / HPOSG.hbm.xml/> 
< mapping resource =com / hposg / hibernate / resources / Tradeable.hbm.xml/> 
< mapping resource =com / hposg / hibernate / resources / GlobalGameConfig.hbm.xml/> 
< mapping resource =com / hposg / hibernate / resources / Announcement.hbm.xml/> 
< mapping resource =com / hposg / hibernate / resources / AdviserMsg.hbm.xml/> 
< mapping resource =com / hposg / hibernate / resources / SystemConfiguration.hbm.xml/> 
< / session-factory> 
  

btw我没有使用c3p0连接池，我不知道这是否相关。只是觉得提及它。

任何想法？ Hibernate使用原始连接池机制 rel =nofollow a>，这不适合于生产目的（它甚至在日志文件中说过！）。您应始终 使用连接池机制，无论是由您的容器提供的连接池机制，无论它是捆绑在您的应用程序中的机制（例如c3p0）。你看到的例外是因为MySQL关闭了Hibernate仍在使用的旧连接。你可以尝试添加一个JDBC URL选项，比如autoReconnect，但这不是一个长期的解决方案。

理想情况下，您应该配置容器以通过JNDI为应用程序提供连接。这很容易通过JBoss中的-ds.xml文件或Tomcat的context.xml来完成。

I've got a J2EE application which uses JSP pages as front end and Struts2 as controller. I also use Hibernate to map my objects into a MySql DB. when I deploy the application on the server It works fine but after an unpredictable period of time (like 1 or two days) wherever I've used hibernate queries I keep getting this error:

org.hibernate.exception.JDBCConnectionException: could not execute query

what makes it more interesting is the fact that when this situation happens, it's not like 100% of queries end up to this exception! sometimes some of them are executed properly.

an example piece of code in which the error occurs:

public synchronized static Player getPlayerByID(String playerID) throws NoSuchPlayer {

    Session session = HibernateUtil.getSessionFactory().getCurrentSession();
    session.beginTransaction();
    Player player = (Player) session.createQuery(
            "from Player as player where player.loginName = '" + playerID
                    + "'").uniqueResult();//THE ERROR HAPPENS HERE
    session.getTransaction().commit();

    if (player == null)
        throw new NoSuchPlayer();

    return player;
}

and this is the respective stacktrace:

    'org.hibernate.exception.JDBCConnectionException: could not execute query
        at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:99)
        at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
        at org.hibernate.loader.Loader.doList(Loader.java:2297)
        at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2172)
        at org.hibernate.loader.Loader.list(Loader.java:2167)
        at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:448)
        at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:363)
        at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:196)
        at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1258)
        at org.hibernate.impl.QueryImpl.list(QueryImpl.java:102)
        at org.hibernate.impl.AbstractQueryImpl.uniqueResult(AbstractQueryImpl.java:859)
        at com.hposg.domain.HPOSG.getPlayerByID(HPOSG.java:117)
        at com.hposg.login.UserSession.getPlayerById(UserSession.java:39)
        at com.hposg.controller.struts.BuyAction.execute(BuyAction.java:74)
        at sun.reflect.GeneratedMethodAccessor1098.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:616)
        at com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:441)
        at com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:280)
        at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:243)
        at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:165)
        at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
        at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
        at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:252)
        at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)
        at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
        at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
        at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:122)
        at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
        at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)
        at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
        at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
        at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)
        at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
        at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
        at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:179)
        at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
        at org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:75)
        at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
        at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:94)
        at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
        at org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:235)
        at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
        at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:89)
        at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
        at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:130)
        at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
        at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:267)
        at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
        at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:126)
        at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
        at com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:138)
        at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
        at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
        at com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:165)
        at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
        at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)
        at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
        at com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:179)
        at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
        at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:176)
        at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
        at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:52)
        at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:488)
        at org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:395)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
        at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:857)
        at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
        at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
        at java.lang.Thread.run(Thread.java:636)
    Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: No operations allowed after connection closed.Connection was implicitly closed due to underlying exception/error:


** BEGIN NESTED EXCEPTION ** 

com.mysql.jdbc.exceptions.jdbc4.CommunicationsException
MESSAGE: Communications link failure

Last packet sent to the server was 0 ms ago.

STACKTRACE:

com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

Last packet sent to the server was 0 ms ago.
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:532)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:353)
    at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1074)
    at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2583)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2871)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1601)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1710)
    at com.mysql.jdbc.Connection.execSQL(Connection.java:2436)
    at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1402)
    at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1556)
    at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:208)
    at org.hibernate.loader.Loader.getResultSet(Loader.java:1849)
    at org.hibernate.loader.Loader.doQuery(Loader.java:718)
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:270)
    at org.hibernate.loader.Loader.doList(Loader.java:2294)
    at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2172)
    at org.hibernate.loader.Loader.list(Loader.java:2167)
    at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:448)
    at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:363)
    at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:196)
    at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1258)
    at org.hibernate.impl.QueryImpl.list(QueryImpl.java:102)
    at com.hposg.domain.HPOSG.getGameList(HPOSG.java:222)
    at com.hposg.controller.struts.GamesLoadActionAjax.execute(GamesLoadActionAjax.java:23)
    at sun.reflect.GeneratedMethodAccessor1047.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:616)
    at com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:441)
    at com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:280)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:243)
    at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:165)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
    at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:252)
    at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
    at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:122)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
    at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
    at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
    at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:179)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
    at org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:75)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
    at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:94)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
    at org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:235)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
    at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:89)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
    at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:130)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
    at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:267)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
    at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:126)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
    at com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:138)
    at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
    at com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:165)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
    at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
    at com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:179)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
    at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:176)
    at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
    at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:52)
    at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:488)
    at org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:395)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:857)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
    at java.lang.Thread.run(Thread.java:636)
Caused by: java.io.EOFException
    at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:1958)
    at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2372)
    ... 83 more


** END NESTED EXCEPTION **


    at sun.reflect.GeneratedConstructorAccessor139.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:532)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:353)
    at com.mysql.jdbc.Util.getInstance(Util.java:336)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:985)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:957)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:927)
    at com.mysql.jdbc.Connection.checkClosed(Connection.java:1103)
    at com.mysql.jdbc.Connection.prepareStatement(Connection.java:3865)
    at com.mysql.jdbc.Connection.prepareStatement(Connection.java:3831)
    at org.hibernate.jdbc.AbstractBatcher.getPreparedStatement(AbstractBatcher.java:534)
    at org.hibernate.jdbc.AbstractBatcher.getPreparedStatement(AbstractBatcher.java:452)
    at org.hibernate.jdbc.AbstractBatcher.prepareQueryStatement(AbstractBatcher.java:161)
    at org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1596)
    at org.hibernate.loader.Loader.doQuery(Loader.java:717)
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:270)
    at org.hibernate.loader.Loader.doList(Loader.java:2294)
    ... 74 more
'

and finally this is my hibernate config file:

<?xml version='1.0' encoding='utf-8'?>

    <!-- Database connection settings -->
    <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
    <property name="hibernate.connection.url">
        jdbc:mysql://localhost/hposg?characterEncoding=UTF-8
    </property>
    <property name="connection.username">root</property>
    <property name="connection.password"></property>

    <!-- JDBC connection pool (use the built-in) -->
    <property name="connection.pool_size">1</property>

    <!-- Echo all executed SQL to stdout -->
    <property name="show_sql">true</property>

    <!-- SQL dialect -->
    <property name="dialect">org.hibernate.dialect.MySQLDialect</property>

    <!-- Enable Hibernate's automatic session context management -->
    <property name="current_session_context_class">thread</property>

    <!-- Disable the second-level cache -->
    <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>

    <!-- Drop and re-create the database schema on startup -->
    <property name="hbm2ddl.auto">update</property>

  <!-- Mapping files -->

  <mapping resource="com/hposg/hibernate/resources/Player.hbm.xml"/>
  <mapping resource="com/hposg/hibernate/resources/Game.hbm.xml"/>
  <mapping resource="com/hposg/hibernate/resources/Portfolio.hbm.xml"/>
  <mapping resource="com/hposg/hibernate/resources/Purchase.hbm.xml"/>
  <mapping resource="com/hposg/hibernate/resources/Sale.hbm.xml"/>
  <mapping resource="com/hposg/hibernate/resources/Message.hbm.xml"/>
  <mapping resource="com/hposg/hibernate/resources/Admin.hbm.xml"/>
  <mapping resource="com/hposg/hibernate/resources/News.hbm.xml"/>
  <mapping resource="com/hposg/hibernate/resources/Invitation.hbm.xml"/>
  <mapping resource="com/hposg/hibernate/resources/CustomGameCreationRequest.hbm.xml"/>
  <mapping resource="com/hposg/hibernate/resources/Alert.hbm.xml"/>
  <mapping resource="com/hposg/hibernate/resources/AlertLimits.hbm.xml"/>
  <mapping resource="com/hposg/hibernate/resources/StockIndex.hbm.xml"/>      
  <mapping resource="com/hposg/hibernate/resources/HPOSG.hbm.xml"/>  
  <mapping resource="com/hposg/hibernate/resources/Tradeable.hbm.xml"/>
  <mapping resource="com/hposg/hibernate/resources/GlobalGameConfig.hbm.xml"/>
  <mapping resource="com/hposg/hibernate/resources/Announcement.hbm.xml"/>  
  <mapping resource="com/hposg/hibernate/resources/AdviserMsg.hbm.xml"/>
  <mapping resource="com/hposg/hibernate/resources/SystemConfiguration.hbm.xml"/>  
</session-factory>

btw I'm not using c3p0 connection pool, I don't know if this is relevant or not. just felt to mention it.

Any ideas?

解决方案

Hibernate uses a primitive connection pooling mechanism, which is not suitable for production purposes (it even says that in the log file!). You should always use a connection pooling mechanism, be it the one provided by your container, be it a mechanism bundled in your application (c3p0, for instance). The exception you are seeing is because MySQL closed an "old" connection which Hibernate is still using. You can try to add a JDBC URL option, like "autoReconnect", but that's really not a long-term solution.

Ideally, you should configure your container to supply the connections to your application through JNDI. This is easily done with a "-ds.xml" file in JBoss or with a context.xml for Tomcat.

这篇关于继续收到org.hibernate.exception.JDBCConnectionException：无法执行查询的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！