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java - hibernate、jpa 和 c3p0 的连接异常

转载 作者：行者123 更新时间：2023-12-01 12:08:19 27 4
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我在使用 c3p0-0.9.5-pre10、hibernate-release-4.2.16.Final 和 JPA 2.0 时遇到问题。当 mysql 处于非 Activity 状态 8 小时或更长时间时，我会收到此错误，并且我的应用程序不再工作。为什么 C3P0 不起作用？

Dec 11, 2014 7:45:15 AM com.sun.faces.context.AjaxExceptionHandlerImpl handlePartialResponseError
SEVERE: javax.faces.el.EvaluationException: javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: could not prepare statement
    at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:101)
    at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)
    at javax.faces.component.UICommand.broadcast(UICommand.java:315)
    at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:790)
    at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1282)
    at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
    at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:646)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:72)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
    at org.apache.coyote.ajp.AjpProcessor.process(AjpProcessor.java:200)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:744)
Caused by: javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: could not prepare statement
    at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1387)
    at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1310)
    at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:277)
    at br.com.clikyapp1.modelo.UsuarioDAO.login(UsuarioDAO.java:27)
    at br.com.clikyapp1.controle.ControleLogin.efetuarLogin(ControleLogin.java:29)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.apache.el.parser.AstValue.invoke(AstValue.java:278)
    at org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:274)
    at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
    at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:87)
    ... 27 more
Caused by: org.hibernate.exception.GenericJDBCException: could not prepare statement
    at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:54)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:124)
    at org.hibernate.engine.jdbc.internal.StatementPreparerImpl$StatementPreparationTemplate.prepareStatement(StatementPreparerImpl.java:193)
    at org.hibernate.engine.jdbc.internal.StatementPreparerImpl.prepareQueryStatement(StatementPreparerImpl.java:157)
    at org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1881)
    at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1858)
    at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1838)
    at org.hibernate.loader.Loader.doQuery(Loader.java:906)
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:348)
    at org.hibernate.loader.Loader.doList(Loader.java:2550)
    at org.hibernate.loader.Loader.doList(Loader.java:2536)
    at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2366)
    at org.hibernate.loader.Loader.list(Loader.java:2361)
    at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:495)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:357)
    at org.hibernate.engine.query.spi.HQLQueryPlan.performList(HQLQueryPlan.java:198)
    at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1194)
    at org.hibernate.internal.QueryImpl.list(QueryImpl.java:101)
    at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:268)
    ... 37 more
Caused by: java.sql.SQLException: A problem occurred while trying to acquire a cached PreparedStatement in a background thread.
    at com.mchange.v2.c3p0.stmt.GooGooStatementCache.acquireStatement(GooGooStatementCache.java:571)
    at com.mchange.v2.c3p0.stmt.GooGooStatementCache.checkoutStatement(GooGooStatementCache.java:204)
    at com.mchange.v2.c3p0.impl.NewPooledConnection.checkoutStatement(NewPooledConnection.java:321)
    at com.mchange.v2.c3p0.impl.NewProxyConnection.prepareStatement(NewProxyConnection.java:1086)
    at org.hibernate.engine.jdbc.internal.StatementPreparerImpl$5.doPrepare(StatementPreparerImpl.java:159)
    at org.hibernate.engine.jdbc.internal.StatementPreparerImpl$StatementPreparationTemplate.prepareStatement(StatementPreparerImpl.java:183)
    ... 53 more
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: No operations allowed after connection closed.
    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:526)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:408)
    at com.mysql.jdbc.Util.getInstance(Util.java:383)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1023)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:997)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:983)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:928)
    at com.mysql.jdbc.ConnectionImpl.throwConnectionClosedException(ConnectionImpl.java:1323)
    at com.mysql.jdbc.ConnectionImpl.checkClosed(ConnectionImpl.java:1315)
    at com.mysql.jdbc.ConnectionImpl.prepareStatement(ConnectionImpl.java:4533)
    at com.mysql.jdbc.ConnectionImpl.prepareStatement(ConnectionImpl.java:4498)
    at sun.reflect.GeneratedMethodAccessor199.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask.run(GooGooStatementCache.java:546)
    at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696)

这是我的 persistence.xml

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0"
    xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
    <persistence-unit name="clikyapp1" transaction-type="RESOURCE_LOCAL">

        <!-- <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider> -->
         <provider>org.hibernate.ejb.HibernatePersistence</provider>   

        <class>br.com.clikyapp1.bean.Cultura</class>
        <class>br.com.clikyapp1.bean.Cidade</class>
        <class>br.com.clikyapp1.bean.Estado</class>
        <class>br.com.clikyapp1.bean.TipoDespesa</class>
        <class>br.com.clikyapp1.bean.Safra</class>
        <class>br.com.clikyapp1.bean.TipoContrato</class>
        <class>br.com.clikyapp1.bean.Area</class>
        <class>br.com.clikyapp1.bean.Armazem</class>
        <class>br.com.clikyapp1.bean.Conta</class>
        <class>br.com.clikyapp1.bean.Parceiro</class>
        <class>br.com.clikyapp1.bean.Usuario</class>
        <class>br.com.clikyapp1.bean.Fixacao</class>
        <class>br.com.clikyapp1.bean.Venda</class>
        <class>br.com.clikyapp1.bean.Modalidade</class>
        <class>br.com.clikyapp1.bean.LocalEntrega</class>
        <class>br.com.clikyapp1.bean.VinculoContrato</class>
        <class>br.com.clikyapp1.bean.OcorrenciaContrato</class>
        <class>br.com.clikyapp1.bean.LocalEntregaContrato</class>
        <class>br.com.clikyapp1.bean.Contrato</class>
        <class>br.com.clikyapp1.bean.Indexador</class>
        <class>br.com.clikyapp1.bean.CessaoCredito</class>
        <class>br.com.clikyapp1.bean.Penhor</class>
        <properties>
            <property name="javax.persistence.jdbc.user" value="root" />
            <property name="javax.persistence.jdbc.password" value="********" />
            <property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/clikyapp1?autoReconnect=true" />
            <property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
            <property name="hibernate.cache.provider_class" value="org.hibernate.cache.NoCacheProvider" />
            <property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5Dialect" />
            <property name="hibernate.connection.autocommit" value="false" />
            <property name="hibernate.hbm2ddl.auto" value="update" />

            <property name="hibernate.temp.use_jdbc_metadata_defaults"
                value="false" />

            <property name="hibernate.connection.provider_class"
                value="org.hibernate.connection.C3P0ConnectionProvider" />
            <property name="hibernate.c3p0.min_size" value="7"/>
            <property name="hibernate.c3p0.max_size" value="53"/>
            <property name="hibernate.c3p0.timeout" value="100"/>
            <property name="hibernate.c3p0.max_statements" value="50"/>
            <property name="hibernate.c3p0.idle_test_period" value="1000"/>
            <property name="hibernate.c3p0.validate" value="true"/>
            <property name="hibernate.connection.provider_class" value="org.hibernate.service.jdbc.connections.internal.C3P0ConnectionProvider"/>

        </properties>
    </persistence-unit>
</persistence>

有什么想法吗？？？谢谢...

最佳答案

您的应用程序可能会保持打开的连接，而不是根据需要获取它们并立即关闭它们(将它们签回到池中)。要验证这一点，请尝试设置以下两个参数:

  1. unreturnedConnectionTimeout
  2. debugUnreturnedConnectionStackTraces

有关更多说明，另请参阅 here .

设置unreturnedConnectionTimeout一个足够大的值，普通的数据库操作应该可以轻松完成。 (除非您正在处理大型数据集或复杂查询，否则 60 秒可能绰绰有余，但这确实取决于您的应用程序。)设置 debugUnreturnedConnectionStackTraces至true 。然后查看日志以查看未返回的连接是否已过期以及在您设置的超时过后是否记录了堆栈跟踪。检查堆栈跟踪:它将指向您检查未立即返回的连接的代码。

如果您的应用程序 checkout Connections并使它们保持打开状态，c3p0 无法测试它们、使它们过期或保证它们的“新鲜度”。应用程序应注意“及时”检查连接，并立即返回它们。

还有:您的maxStatements设置不太适合可扩展到 53 的池。当您解决应用程序的问题时，我将 maxStatements 设置为零(无语句缓存)。然后，如果您想尝试通过语句缓存来增强性能，则需要对 maxStatements 使用更大的值。 ，或者考虑使用更容易理解的 maxStatementsPerConnection 。更多讨论here .

最后:要通过 hibernate 设置这些 c3p0 参数，您可以使用类似 hibernate.c3p0. unreturnedConnectionTimeout 的属性。 。请参阅here .

关于java - hibernate、jpa 和 c3p0 的连接异常，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/27419919/

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