Java Hibernate-org.Hibernate.exception.GenericJDBCException:无法打开连接

为了解决DB连接过多和空闲连接过多的问题，我们对配置文件进行了以下更改-

c3p0.min_size=1
c3p0.max_size=20
c3p0.timeout=1800
c3p0.max_statements=50
connection.release_mode=on_close

之后，在尝试运行应用程序时，我们得到以下异常。请告知发生这种情况的原因以及如何纠正-

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类型异常报告

message org.hibernate.exception.GenericJDBCException: Cannot open connection

description The server encountered an internal error that prevented it from fulfilling this request.

exception

javax.servlet.ServletException: org.hibernate.exception.GenericJDBCException: Cannot open connection
    org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:286)
    org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
    org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:462)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    com.alci.filters.ParamFilter.doFilter(ParamFilter.java:27)
root cause

org.hibernate.exception.GenericJDBCException: Cannot open connection
    org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:126)
    org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:114)
    org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
    org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:52)
    org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:449)
    org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:167)
    org.hibernate.jdbc.AbstractBatcher.prepareQueryStatement(AbstractBatcher.java:161)
    org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1577)
    org.hibernate.loader.Loader.doQuery(Loader.java:696)
    org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259)
    org.hibernate.loader.Loader.doList(Loader.java:2232)
    org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2129)
    org.hibernate.loader.Loader.list(Loader.java:2124)
    org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:401)
    org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:363)
    org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:196)
    org.hibernate.impl.SessionImpl.list(SessionImpl.java:1149)
    org.hibernate.impl.QueryImpl.list(QueryImpl.java:102)
    com.alci.common.LoginAction.login(LoginAction.java:127)
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    java.lang.reflect.Method.invoke(Method.java:597)
    org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:269)
    org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:170)
    org.apache.struts.chain.commands.servlet.ExecuteAction.execute(ExecuteAction.java:58)
    org.apache.struts.chain.commands.AbstractExecuteAction.execute(AbstractExecuteAction.java:67)
    org.apache.struts.chain.commands.ActionCommandBase.execute(ActionCommandBase.java:51)
    org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
    org.apache.commons.chain.generic.LookupCommand.execute(LookupCommand.java:304)
    org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
    org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:283)
    org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
    org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:462)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    com.alci.filters.ParamFilter.doFilter(ParamFilter.java:27)
root cause

java.sql.SQLException: Connections could not be acquired from the underlying database!
    com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:106)
    com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:529)
    com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:128)
    org.hibernate.connection.C3P0ConnectionProvider.getConnection(C3P0ConnectionProvider.java:78)
    org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:446)
    org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:167)
    org.hibernate.jdbc.AbstractBatcher.prepareQueryStatement(AbstractBatcher.java:161)
    org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1577)
    org.hibernate.loader.Loader.doQuery(Loader.java:696)
    org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259)
    org.hibernate.loader.Loader.doList(Loader.java:2232)
    org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2129)
    org.hibernate.loader.Loader.list(Loader.java:2124)
    org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:401)
    org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:363)
    org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:196)
    org.hibernate.impl.SessionImpl.list(SessionImpl.java:1149)
    org.hibernate.impl.QueryImpl.list(QueryImpl.java:102)
    com.alci.common.LoginAction.login(LoginAction.java:127)
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    java.lang.reflect.Method.invoke(Method.java:597)
    org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:269)
    org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:170)
    org.apache.struts.chain.commands.servlet.ExecuteAction.execute(ExecuteAction.java:58)
    org.apache.struts.chain.commands.AbstractExecuteAction.execute(AbstractExecuteAction.java:67)
    org.apache.struts.chain.commands.ActionCommandBase.execute(ActionCommandBase.java:51)
    org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
    org.apache.commons.chain.generic.LookupCommand.execute(LookupCommand.java:304)
    org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
    org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:283)
    org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
    org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:462)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    com.alci.filters.ParamFilter.doFilter(ParamFilter.java:27)
root cause

com.mchange.v2.resourcepool.CannotAcquireResourceException: A ResourcePool could not acquire a resource from its primary factory or source.
    com.mchange.v2.resourcepool.BasicResourcePool.awaitAvailable(BasicResourcePool.java:1319)
    com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java:557)
    com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:477)
    com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:525)
    com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:128)
    org.hibernate.connection.C3P0ConnectionProvider.getConnection(C3P0ConnectionProvider.java:78)
    org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:446)
    org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:167)
    org.hibernate.jdbc.AbstractBatcher.prepareQueryStatement(AbstractBatcher.java:161)
    org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1577)
    org.hibernate.loader.Loader.doQuery(Loader.java:696)
    org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259)
    org.hibernate.loader.Loader.doList(Loader.java:2232)
    org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2129)
    org.hibernate.loader.Loader.list(Loader.java:2124)
    org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:401)
    org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:363)
    org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:196)
    org.hibernate.impl.SessionImpl.list(SessionImpl.java:1149)
    org.hibernate.impl.QueryImpl.list(QueryImpl.java:102)
    com.alci.common.LoginAction.login(LoginAction.java:127)
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    java.lang.reflect.Method.invoke(Method.java:597)
    org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:269)
    org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:170)
    org.apache.struts.chain.commands.servlet.ExecuteAction.execute(ExecuteAction.java:58)
    org.apache.struts.chain.commands.AbstractExecuteAction.execute(AbstractExecuteAction.java:67)
    org.apache.struts.chain.commands.ActionCommandBase.execute(ActionCommandBase.java:51)
    org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
    org.apache.commons.chain.generic.LookupCommand.execute(LookupCommand.java:304)
    org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
    org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:283)
    org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
    org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:462)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    com.alci.filters.ParamFilter.doFilter(ParamFilter.java:27)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.36 logs.

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数据库连接已用完

这意味着两件事：

由于查询速度慢，您的事务花费的时间太长，因此连接被占用的时间太长

您的流量需求非常高，无法容纳20个连接池大小

我建议你阅读以下内容

:

ON_CLOSE-本质上是上述遗留行为。这个 Hibernate会话在第一次需要执行时获得连接 一些JDBC访问并保持该连接，直到会话结束 关闭

on_close-表示使用ConnectionReleaseMode.on_close。这个设置是 留作向后兼容性，但它的使用是非常不鼓励的

---

请尝试改用“自动”。

这有时是由于超时引起的。增加超时时间，有望解决问题

c3p0.timeout=6000

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你能发布根原因的完整堆栈跟踪吗？它是一个共享的tomcat；因此，您不能立即访问完整堆栈跟踪。这是一个测试环境，因此流量非常小。另一方面，这个异常在登录时出现，所以在登录时查询速度较慢，我猜在调试时启用C3P0日志，这样您就可以实际看到请求了多少个连接以及它们释放的速度有多快。检查我更新的响应，我想您不应该使用连接。release\u mode=On\u close选项。@vladmin假设，我有一个大型应用程序，其中在服务层使用spring事务管理器，在dao层使用hibernate会话，而不是关闭。此语句是否会在

hibernate.cfg.xml

中关闭这些打开的会话？@vladmin我可以将此工具用于hibernate SessionFactory吗？如何使用它？

connection.release_mode=on_close

c3p0.timeout=6000