当出现c3p0 连接池显示以下错误：
1、检查你c3p0设置允许的最大连接数
2、查看当前Oracle允许的最大连接数
3、以上没问题，确认长链接的策略
[INFO] [c3p0] The following Exceptions occurred while trying to clean up a Connection‘s stranded resources: <com.mchange.v2.c3p0.impl.NewPooledConnection.markClosedProxyConnection()> (NewPooledConnection.java:303)
[INFO] [c3p0 -- conection resource close Exception] <com.mchange.v2.c3p0.impl.NewPooledConnection.markClosedProxyConnection()> (NewPooledConnection.java:310)
java.sql.SQLRecoverableException: 关闭的连接
at oracle.jdbc.driver.PhysicalConnection.needLine(PhysicalConnection.java:5389)
at oracle.jdbc.driver.OracleStatement.closeOrCache(OracleStatement.java:1578)
at oracle.jdbc.driver.OracleStatement.close(OracleStatement.java:1563)
at oracle.jdbc.driver.OracleStatementWrapper.close(OracleStatementWrapper.java:94)
at oracle.jdbc.driver.OraclePreparedStatementWrapper.close(OraclePreparedStatementWrapper.java:80)
at oracle.jdbc.driver.OracleCallableStatementWrapper.close(OracleCallableStatementWrapper.java:1434)
at com.mchange.v2.c3p0.impl.NewPooledConnection.cleanupUncachedStatements(NewPooledConnection.java:576)
at com.mchange.v2.c3p0.impl.NewPooledConnection.markClosedProxyConnection(NewPooledConnection.java:297)
at com.mchange.v2.c3p0.impl.NewProxyConnection.close(NewProxyConnection.java:1246)
at com.tzsw.plat.commons.DBUtil.closeConnection(DBUtil.java:615)
at com.tzsw.apps.webservice.tzBusinesspro.p_tx_jydj(tzBusinesspro.java:1405)
at com.tzsw.apps.webservice.WebserviceService.p_tx_jydj(WebserviceService.java:546)
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 org.apache.axis.providers.java.RPCProvider.invokeMethod(RPCProvider.java:397)
at org.apache.axis.providers.java.RPCProvider.processMessage(RPCProvider.java:186)
at org.apache.axis.providers.java.JavaProvider.invoke(JavaProvider.java:323)
at org.apache.axis.strategies.InvocationStrategy.visit(InvocationStrategy.java:32)
at org.apache.axis.SimpleChain.doVisiting(SimpleChain.java:118)
at org.apache.axis.SimpleChain.invoke(SimpleChain.java:83)
at org.apache.axis.handlers.soap.SOAPService.invoke(SOAPService.java:453)
at org.apache.axis.server.AxisServer.invoke(AxisServer.java:281)
at org.apache.axis.transport.http.AxisServlet.doPost(AxisServlet.java:699)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:650)
at org.apache.axis.transport.http.AxisServletBase.service(AxisServletBase.java:327)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:110)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:506)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:962)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:445)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1115)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:662)
p_tx_jydj_result2:
java.sql.SQLRecoverableException: IO 错误: Connection timed out
at oracle.jdbc.driver.T4CCallableStatement.executeForRows(T4CCallableStatement.java:1062)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1329)
at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:3584)
at oracle.jdbc.driver.OraclePreparedStatement.execute(OraclePreparedStatement.java:3685)
at oracle.jdbc.driver.OracleCallableStatement.execute(OracleCallableStatement.java:4714)
at oracle.jdbc.driver.OraclePreparedStatementWrapper.execute(OraclePreparedStatementWrapper.java:1376)
at com.mchange.v2.c3p0.impl.NewProxyCallableStatement.execute(NewProxyCallableStatement.java:3044)
at com.tzsw.apps.webservice.tzBusinesspro.p_tx_jydj_rollback(tzBusinesspro.java:1549)
原文地址：https://www.cnblogs.com/xunyi/p/11656130.html