java - Hibernate 和 Mysql 超时问题，不适用于 c3p0

Question

我已经为Hibernate 和Mysql 超时错误困扰了一个星期。显然，在我的 Hibernate/MySQL 运行 8 小时后(这是 Mysql 中的默认超时值)，我遇到了异常。我还添加了 c3p0。但这没有帮助。

请指教非常感谢

这是我的 hibernate 配置:

<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<!--Account MYSQL Username Info-->
<property name="hibernate.connection.url">jdbc:mysql://localhost/reddragon_test?autoReconnect=true</property>
<property name="hibernate.show_sql">true</property>
<property name="transaction.factory_class">org.hibernate.transaction.JDBCTransactionFactory</property>
<property name="current_session_context_class">thread</property>

<property name="hibernate.c3p0.acquire_increment">3</property>
<property name="hibernate.c3p0.idle_test_period">10</property>
<property name="hibernate.c3p0.timeout">10</property>
<property name="hibernate.c3p0.max_size">15</property>
<property name="hibernate.c3p0.min_size">3</property>
<property name="hibernate.c3p0.max_statements">0</property>
<property name="hibernate.c3p0.preferredTestQuery">select 1;</property>

这是痕迹:

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:2223)
    at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2104)
    at org.hibernate.loader.Loader.list(Loader.java:2099)
    at org.hibernate.loader.criteria.CriteriaLoader.list(CriteriaLoader.java:94)
    at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1569)
    at org.hibernate.impl.CriteriaImpl.list(CriteriaImpl.java:283)
    at com.billing.dao.VmplanDAO.findByExample(VmplanDAO.java:178)
    at com.billing.action.getVmplans.processRequest(getVmplans.java:37)
    at com.billing.action.getVmplans.doGet(getVmplans.java:91)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
    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.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:390)
    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:852)
    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:619)
Caused by: 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: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.SQLError.createCommunicationsException(SQLError.java:1074)
    at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2985)
    at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2871)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3414)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1936)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2060)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2542)
    at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1734)
    at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1885)
    at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeQuery(NewProxyPreparedStatement.java:76)
    at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:186)
    at org.hibernate.loader.Loader.getResultSet(Loader.java:1787)
    at org.hibernate.loader.Loader.doQuery(Loader.java:674)
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
    at org.hibernate.loader.Loader.doList(Loader.java:2220)
    ... 25 more
Caused by: java.net.SocketException: Software caused connection abort: recv failed
    at java.net.SocketInputStream.socketRead0(Native Method)
    at java.net.SocketInputStream.read(SocketInputStream.java:129)
    at com.mysql.jdbc.util.ReadAheadInputStream.fill(ReadAheadInputStream.java:113)
    at com.mysql.jdbc.util.ReadAheadInputStream.readFromUnderlyingStreamIfNecessary(ReadAheadInputStream.java:160)
    at com.mysql.jdbc.util.ReadAheadInputStream.read(ReadAheadInputStream.java:188)
    at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:2428)
    at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2882)
    ... 38 more
java.lang.NullPointerException
java.lang.NullPointerException
    at com.billing.action.getVmplans.processRequest(getVmplans.java:38)
    at com.billing.action.getVmplans.doGet(getVmplans.java:91)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
    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.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:390)
    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:852)
    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:619)

Answer 1

老实说，您的问题有三种解决方案。我将解释每个解决方案以及每个解决方案的优缺点(最后会出现在您的案例中)

1. 在 mysql my.ini 文件中配置 wait_time_out 属性以确保您的连接超时。这种方法肯定会奏效，但这绝不是一个好的解决方案。你会喜欢在你的应用程序中而不是在数据库中处理这件事，因为有时你可能无法对数据库进行那么多的控制，或者其他一些应用程序可能正在使用相同的数据库。

2. 使用 apache dbcp 而不是 c3p0。您可以在您提供数据库名称的服务器的 context.xml 中配置 dbcp。这种方法可行，但这种方法的问题是您可能计划将来切换到其他应用程序服务器，比如 JBOSS，在那种情况下，我不是 apache dbcp 是否可行。我没有在 jboss 上尝试过，但我猜它不会。

3. 第三种方式是你选择的方式

在您的情况下，您缺少一个属性，即

<property name="connection.provider_class">
  org.hibernate.connection.C3P0ConnectionProvider
</property>

到目前为止，您一定已经注意到在服务器启动期间 c3p0 根本没有初始化。好吧，如果您在设置此属性后考虑您的代码将工作，我很抱歉地说，它不会。

这是由于 spring 代码中的错误。您可以通过查看 LocalSessionFactoryBean 的源代码来验证这一点，它只是忽略上面设置的属性值并将其设置为 LocalDataSourceConnectionProvider 并且您的 c3p0 永远不会被初始化。

您可以提供 LocalSessionFactoryBean 的自定义实现，您可以在其中将提供程序类硬编码为 C3P0ConnectionProvider。

现在重新启动服务器并注意您的 c3p0 已初始化，现在您可以处理 c3p0 的详细信息。

到目前为止，您遇到的问题是 c3p0 从未初始化并且不在画面中。

希望这对您有所帮助。