Java Spring中遇到这样的异常？

Question

org.springframework.transaction.CannotCreateTransactionException: Could not open JDBC Connection for transaction; nested exception is java.sql.SQLException: com.mchange.v2.c3p0.ComboPooledDataSource [ java.beans.IntrospectionException: java.lang.reflect.InvocationTargetException [numThreadsAwaitingCheckoutDefaultUser] ] has been closed() -- you can no longer use it.
    at org.springframework.jdbc.datasource.DataSourceTransactionManager.doBegin(DataSourceTransactionManager.java:245)
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:373)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.createTransactionIfNecessary(TransactionAspectSupport.java:427)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:276)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:208)
    at com.sun.proxy.$Proxy83.checkAccountStatus(Unknown Source)
    at com.mc.arkcloud.server.deal.timer.IscsiNetStoreChecker.run(IscsiNetStoreChecker.java:48)
    at java.util.TimerThread.mainLoop(Timer.java:555)
    at java.util.TimerThread.run(Timer.java:505)
Caused by: java.sql.SQLException: com.mchange.v2.c3p0.ComboPooledDataSource [ java.beans.IntrospectionException: java.lang.reflect.InvocationTargetException [numThreadsAwaitingCheckoutDefaultUser] ] has been closed() -- you can no longer use it.
    at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.assertCpds(AbstractPoolBackedDataSource.java:447)
    at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getPoolManager(AbstractPoolBackedDataSource.java:459)
    at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:128)
    at org.springframework.jdbc.datasource.DataSourceTransactionManager.doBegin(DataSourceTransactionManager.java:204)
    ... 12 more

Answer 1

class12.jar パッケージが追加されていないため、データベース接続が不安定です

を追加してください。

Answer 2

データベースリンクが閉じられています。まず、直接接続に問題がないか確認してください。問題がない場合は、接続プールから取得した接続がタイムアウトして切断されている可能性があります。プールとデータベース自体のタイムアウト構成についての質問