我使用Struts2 + JSP + Tomcat6+Hibernate+Mysql作为我的J2EE应用程序框架。按照这个]主题，我遇到了出现此错误的问题：
org.hibernate.exception.JDBCConnectionException: could not execute query
看来是由于mysql在n小时后关闭了它的连接。当人们回答时，我更改了hibernate配置以通过JNDI获得数据库连接。这是我采取的操作步骤：
我的hibernate.cfg.xml：
<hibernate-configuration> <session-factory> <property name="connection.datasource">java:comp/env/jdbc/hposg</property> <property name="dialect">org.hibernate.dialect.MySQLDialect</property> <property name="show_sql">true</property> <property name="current_session_context_class">thread</property> <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property> <property name="hbm2ddl.auto">update</property> <property name="hibernate.max_fetch_depth">3</property> <!-- Mapping files --> </session-factory> </hibernate-configuration>
我放入META-INF详细信息中的context.xml文件：
<Context> <Resource name="jdbc/hposg" global="jdbc/hposg" auth="Container" type="javax.sql.DataSource" username="root" password="" driverClassName="com.mysql.jdbc.Driver" url="jdbc:mysql://localhost:3306/hposg?autoReconnect=true&characterEncoding=UTF-8" maxActive="8" maxIdle="4"/> </Context>
以及web.xml中的这些修改：
<resource-ref> <description>DB Connection</description> <res-ref-name>jdbc/hposg</res-ref-name> <res-type>javax.sql.DataSource</res-type> <res-auth>Container</res-auth> </resource-ref>
奇怪的是，我仍然遇到相同的错误！这是堆栈跟踪：
'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.PortfolioLoadAction.execute(PortfolioLoadAction.java:72) at sun.reflect.GeneratedMethodAccessor1032.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.CommunicationsException: Communications link failure Last packet sent to the server was 0 ms ago. at sun.reflect.GeneratedConstructorAccessor109.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.SQLError.createCommunicationsException(SQLError.java:1074) at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:2720) at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1582) 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.apache.tomcat.dbcp.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:93) 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) ... 74 more Caused by: java.net.SocketException: Broken pipe at java.net.SocketOutputStream.socketWrite0(Native Method) at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:109) at java.net.SocketOutputStream.write(SocketOutputStream.java:153) at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:82) at java.io.BufferedOutputStream.write(BufferedOutputStream.java:126) at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:2703) ... 85 more '
[编辑]我对context.xml进行了一些更改，该问题似乎已解决：
maxActive="-1" maxIdle="30" validationQuery="SELECT 1" testWhileIdle="true"
[EDIT_2]尽管我之前提到了修改，但不幸的是我仍然遇到相同的错误。有任何想法吗？
在使用Tomcat6 + Hibernate + MySQL（在本例中为Spring）的生产系统中，我们遇到了同样的问题，我们发现的唯一可靠的解决方案是在MySQL配置中将连接超时设置为较大的值。我不记得具体情况，但我相信底层的公共池代码在验证池中的资源有效时存在问题。
我们未尝试的另一种可能性是使用DBCP以外的替代连接池机制。接下来尝试的是C3PO
