我有一个使用c3p0进行连接池的应用程序.当连接到数据库时出现任何问题时,我会收到如下异常：

java.sql.SQLException: An SQLException was provoked by the following failure:

com.mchange.v2.resourcepool.ResourcePoolException: A ResourcePool cannot acquire

a new resource -- the factory or source appears to be down.

at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:106)

at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:65)

at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:62)

at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:531)

at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:128)

at com.pontiflex.monitor.dao.ConnectionManager.getConfigReadOnlyDbConnection(Unknown Source)

at com.pontiflex.monitor.dao.MonitorServiceDAO.getLiveIOCountForOrganization(Unknown Source) at com.pontiflex.monitor.BillingMonitor.getComparisonValueForActivation(Unknown Source)

at com.pontiflex.monitor.AbstractMonitor.isMonitoringActive(Unknown Source)

at com.pontiflex.monitor.AbstractMonitor.generateAlerts(Unknown Source)

at com.pontiflex.monitor.AbstractMonitor.doMonitoring(Unknown Source)

at com.pontiflex.monitor.worker.MonitorWorker.run(Unknown Source)

at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:439)

at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)

at java.util.concurrent.FutureTask.run(FutureTask.java:138) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)

at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)

at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)

at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)

at java.lang.Thread.run(Thread.java:662)

Caused by: com.mchange.v2.resourcepool.ResourcePoolException: A ResourcePool cannot

acquire a new resource -- the factory or source appears to be down.

at com.mchange.v2.resourcepool.BasicResourcePool.awaitAvailable(BasicResourcePool.java:1279)

at com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java:557)

at com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:477)

at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:525)

... 14 more

无论是网络连接问题,服务器问题(连接太多)还是配置问题,都会出现同样的异常.如果我打开mysql jdbc驱动程序和c3p0的调试日志记录,我会获得更多信息：

WARN com.mchange.v2.resourcepool.BasicResourcePool

com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@4e074784 --

Acquisition Attempt Failed!!! Clearing pending acquires. While trying

to acquire a needed new resource, we failed to succeed more than the

maximum number of allowed acquisition attempts (30). Last acquisition

attempt exception:

com.mysql.jdbc.exceptions.MySQLNonTransientConnectionException: Data

source rejected establishment of connection, message from server:

"Too many connections"

at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:921)

at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1070)

at com.mysql.jdbc.Connection.createNewIO(Connection.java:2775)

at com.mysql.jdbc.Connection.(Connection.java:1555)

at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:285)

at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:135)

at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:182)

at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:171)

at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:137)

at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1014)

at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32)

at com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1810)

at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)

有什么办法可以让c3p0在没有调整记录器配置的情况下抛出ResourcePoolException时给出根本原因？