我正在使用hibernate 3和mysql 5.1。当我跨越mysql的wait_timeout后将它连接到数据库时，我无法创建新的session.It给了我以下异常。
ERROR - Communications link failure
Last packet sent to the server was 0 ms ago.
ERROR - JDBC rollback failed
com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Connection.close() has already been called. Invalid operation in this state.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
at com.mysql.jdbc.Util.getInstance(Util.java:381)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:984)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:926)
at com.mysql.jdbc.ConnectionImpl.getMutex(ConnectionImpl.java:3032)
at com.mysql.jdbc.ConnectionImpl.rollback(ConnectionImpl.java:4606)
at org.hibernate.transaction.JDBCTransaction.rollbackAndResetAutoCommit(JDBCTransaction.java:183)
at org.hibernate.transaction.JDBCTransaction.rollback(JDBCTransaction.java:162)
at com.arosys.hibernateDao.HibernateFactory.rollback(HibernateFactory.java:95)
at com.arosys.hibernateDao.AbstractDao.handleException(AbstractDao.java:171)
at com.arosys.hibernateDao.AbstractDao.fetchUserData(AbstractDao.java:209)
at com.arosys.beansDao.CredentialsDao.fetchUserData(CredentialsDao.java:83)
at org.ArosysLogin.server.GWTLoginImpl.myMethod(GWTLoginImpl.java:87)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:569)
at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServiceServlet.java:208)
at com.google.gwt.user.server.rpc.RemoteServiceServlet.processPost(RemoteServiceServlet.java:248)
at com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(AbstractRemoteServiceServlet.java:62)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
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:662)
ERROR - Couldn't rollback Transaction
org.hibernate.TransactionException: JDBC rollback failed
at org.hibernate.transaction.JDBCTransaction.rollback(JDBCTransaction.java:170)
at com.arosys.hibernateDao.HibernateFactory.rollback(HibernateFactory.java:95)
at com.arosys.hibernateDao.AbstractDao.handleException(AbstractDao.java:171)
at com.arosys.hibernateDao.AbstractDao.fetchUserData(AbstractDao.java:209)
at com.arosys.beansDao.CredentialsDao.fetchUserData(CredentialsDao.java:83)
at org.ArosysLogin.server.GWTLoginImpl.myMethod(GWTLoginImpl.java:87)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:569)
at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServiceServlet.java:208)
at com.google.gwt.user.server.rpc.RemoteServiceServlet.processPost(RemoteServiceServlet.java:248)
at com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(AbstractRemoteServiceServlet.java:62)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
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:662)
我知道异常是由于陈旧的 SessionFactory 对象造成的，并且无法打开会话。当我重新启动应用程序时，它运行正常，直到它没有十字架 wait_timeout time.I引用此链接：http：//www.codefin.net/2007/05/hibernate-and-mysql-connection-timeouts.html并完成相同的过程。我使用C3P0进行连接池但是出来了没有成功。
我在hibernate.cfg.xml文件中使用这些属性：
<property name="connection_provider_class">
org.hibernate.connection.C3P0ConnectionProvider
</property>
<property name="c3p0.minPoolSize">5</property>
<property name="hibernate.c3p0.idle_test_period">20</property>
<property name="hibernate.c3p0.timeout">15</property>
我的mysql wait_timeout是30秒。 另一种方法是每次我需要Session时创建新的SessionFactory对象，但这会产生性能问题并且不想遵循它。
请告诉我我的配置或我出错的地方还需要其他任何东西。
谢谢， 爱玛