本篇内容介绍了“为什么定时任务查询数据时返回连接已关闭”的有关知识，在实际案例的操作过程中，不少人都会遇到这样的困境，接下来就让小编带领大家学习一下如何处理这些情况吧！希望大家仔细阅读，能够学有所成！

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 如下打印的线程栈，原来的定时任务是由线程池形式定时执行，运行一段时间后就会报连接关闭。原来是直接线程访问数据库是没有交给spring的事务去接管的，猜测是连接没有及时释放，然后定时间隔大于异常检测间隔，下次继续用的时候已经被关闭了。

解决方案：定时任务修改为quartz定时任务，将数据库连接交给spring管理。

org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.PersistenceException:
### Error querying database.  Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is com.alibaba.druid.pool.DataSourceClosedException: dataSource already closed at Wed Oct 23 11:12:39 CST 2019
### The error may exist in org/xxx/nos/tunnel/mapper/XxxMapper.java (best guess)
### The error may involve org.xxx.mapper.XxxMapper.selectList
### The error occurred while executing a query
### Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is com.alibaba.druid.pool.DataSourceClosedException: dataSource already closed at Wed Oct 23 11:12:39 CST 2019
        at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:77)
        at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:446)
        at com.sun.proxy.$Proxy124.selectList(Unknown Source)
        at org.mybatis.spring.SqlSessionTemplate.selectList(SqlSessionTemplate.java:230)
        at com.baomidou.mybatisplus.core.override.PageMapperMethod.executeForMany(PageMapperMethod.java:173)
        at com.baomidou.mybatisplus.core.override.PageMapperMethod.execute(PageMapperMethod.java:86)
        at com.baomidou.mybatisplus.core.override.PageMapperProxy.invoke(PageMapperProxy.java:64)
        at com.sun.proxy.$Proxy136.selectList(Unknown Source)
        at org.xxx.framework.service.impl.BaseServiceImpl.list(BaseServiceImpl.java:251)
        at org.xxx.common.mybatisplus.LambdaQueryWrapperChain.list(LambdaQueryWrapperChain.java:79)
        at org.xxx.event.handler.PortCongestionEventHandler.refreshFeedBackMap(PortCongestionEventHandler.java:120)
        at org.xxx.event.handler.PortCongestionEventHandler.lambda$init$0(PortCongestionEventHandler.java:109)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at java.lang.Thread.run(Thread.java:748)
Caused by: org.apache.ibatis.exceptions.PersistenceException:
### Error querying database.  Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is com.alibaba.druid.pool.DataSourceClosedException: dataSource already closed at Wed Oct 23 11:12:39 CST 2019
### The error may exist in org/xxx/nos/tunnel/mapper/XxxMapper.java (best guess)
### The error may involve org.xxx.mapper.XxxMapper.selectList
### The error occurred while executing a query
### Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is com.alibaba.druid.pool.DataSourceClosedException: dataSource already closed at Wed Oct 23 11:12:39 CST 2019
        at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)
        at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:150)
        at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:141)
        at sun.reflect.GeneratedMethodAccessor175.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:433)
        ... 17 common frames omitted
Caused by: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is com.alibaba.druid.pool.DataSourceClosedException: dataSource already closed at Wed Oct 23 11:12:39 CST 2019
        at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:81)
        at org.mybatis.spring.transaction.SpringManagedTransaction.openConnection(SpringManagedTransaction.java:82)
        at org.mybatis.spring.transaction.SpringManagedTransaction.getConnection(SpringManagedTransaction.java:68)
        at org.apache.ibatis.executor.BaseExecutor.getConnection(BaseExecutor.java:338)
        at org.apache.ibatis.executor.SimpleExecutor.prepareStatement(SimpleExecutor.java:84)
        at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:62)
        at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:326)
        at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:156)
        at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:109)
        at sun.reflect.GeneratedMethodAccessor162.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.apache.ibatis.plugin.Plugin.invoke(Plugin.java:63)
        at com.sun.proxy.$Proxy141.query(Unknown Source)
        at com.github.pagehelper.PageInterceptor.intercept(PageInterceptor.java:143)
        at org.apache.ibatis.plugin.Plugin.invoke(Plugin.java:61)
        at com.sun.proxy.$Proxy141.query(Unknown Source)
        at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:148)
        ... 22 common frames omitted
Caused by: com.alibaba.druid.pool.DataSourceClosedException: dataSource already closed at Wed Oct 23 11:12:39 CST 2019
        at com.alibaba.druid.pool.DruidDataSource.getConnectionInternal(DruidDataSource.java:1356)
        at com.alibaba.druid.pool.DruidDataSource.getConnectionDirect(DruidDataSource.java:1253)
        at com.alibaba.druid.filter.FilterChainImpl.dataSource_connect(FilterChainImpl.java:4619)
        at com.alibaba.druid.filter.FilterAdapter.dataSource_getConnection(FilterAdapter.java:2745)
        at com.alibaba.druid.filter.FilterChainImpl.dataSource_connect(FilterChainImpl.java:4615)
        at com.alibaba.druid.filter.stat.StatFilter.dataSource_getConnection(StatFilter.java:680)
        at com.alibaba.druid.filter.FilterChainImpl.dataSource_connect(FilterChainImpl.java:4615)
        at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:1231)
        at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:1223)
        at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:90)
        at org.springframework.jdbc.datasource.DataSourceUtils.fetchConnection(DataSourceUtils.java:157)
        at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:115)
        at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:78)
        ... 39 common frames omitted

“为什么定时任务查询数据时返回连接已关闭”的内容就介绍到这里了，感谢大家的阅读。如果想了解更多行业相关的知识可以关注创新互联网站，小编将为大家输出更多高质量的实用文章！