最近做測試，主執行緒業務處理邏輯較長、發現Mysql 過一段時間會無法連線、極其鬱悶。

使用Connector/J連線MySQL資料庫，程式執行較長時間後就會報以下錯誤：

-| [TID: N/A] | [] | [20210729 15:03:19.211] | [INFO]|[DESKTOP-OOI8H5K] | [pool-6-thread-10]|[c.e.c.s.s.s.impl.CcDsplitServiceImpl] | [--> AddHsplitTask Callable call insertList ,threadName=pool-6-thread-10,count=200] |
-| [TID: N/A] | [] | [20210729 15:03:50.229] | [INFO]|[DESKTOP-OOI8H5K] | [pool-7-thread-4]|[c.e.c.s.s.s.impl.CcDsplitServiceImpl] | [--> AddHsplitTask Callable call end... threadName=pool-7-thread-4,param=AddTask{taskId=1, rowId='lf_1', startDate='2021-07-05', endDate='2021-07-11', split=1065, dayTimeData=15}] |
-| [TID: N/A] | [] | [20210729 15:03:50.232] | [INFO]|[DESKTOP-OOI8H5K] | [pool-3-thread-1]|[c.e.c.s.s.service.impl.CcBaseServiceImpl] | [--> MAPPER_MAP===>{cmsHsplitMapper=org.apache.ibatis.binding.MapperProxy@5de3d9e6, ccBaseMapper=org.apache.ibatis.binding.MapperProxy@43911bff, ccDsplitMapper=org.apache.ibatis.binding.MapperProxy@1c093d2b, ccRowteamMapper=org.apache.ibatis.binding.MapperProxy@6d67b2b, ccSchedulingMapper=org.apache.ibatis.binding.MapperProxy@45b9aefe, ccSchedulingProportionForecastMapper=org.apache.ibatis.binding.MapperProxy@e3c1b55, ccSchedulingTimeslotTrafficMapper=org.apache.ibatis.binding.MapperProxy@5b099fdc, ccSchedulingTrafficDataMapper=org.apache.ibatis.binding.MapperProxy@6e33a8b5, ccServiceLevelTargetMapper=org.apache.ibatis.binding.MapperProxy@66f525d3, ccTrafficDataMapper=org.apache.ibatis.binding.MapperProxy@8fd6ceb, ccTrafficOperationRecordMapper=org.apache.ibatis.binding.MapperProxy@1f9de557}, datasource===>[interface
 
 com.ecej.cc.schedule.server.mapper.CcSchedulingMapper], map.get(datasource[0].toString()===>ccSchedulingMapper] |
-| [TID: N/A] | [] | [20210729 15:03:50.276] | [WARN]|[DESKTOP-OOI8H5K] | [pool-3-thread-1]|[com.zaxxer.hikari.pool.ProxyConnection] | [--> HikariPool-1 - Connection com.mysql.cj.jdbc.ConnectionImpl@7e266d85 marked as broken because of SQLSTATE(08S01), ErrorCode(0)] |
com.mysql.cj.jdbc.exceptions.CommunicationsException: The last packet successfully received from the server was 
 
212,747 milliseconds ago. The last packet sent successfully to the server was 212,749 milliseconds ago. is longer than the server configured value of 'wait_timeout'. You should consider either expiring and/or testing connection validity before use in your application, increasing the server configured values for
 
 client timeouts, or using the Connector/J connection property 'autoReconnect=true' to avoid this problem.
    at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:174)
    at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64)
    at com.mysql.cj.jdbc.ConnectionImpl.isReadOnly(ConnectionImpl.java:1414)
    at com.mysql.cj.jdbc.ConnectionImpl.isReadOnly(ConnectionImpl.java:1399)
    at com.mysql.cj.jdbc.ClientPreparedStatement.checkReadOnlySafeStatement(ClientPreparedStatement.java:307)
    at com.mysql.cj.jdbc.ClientPreparedStatement.execute(ClientPreparedStatement.java:317)
    at com.zaxxer.hikari.pool.ProxyPreparedStatement.execute(ProxyPreparedStatement.java:44)
    at com.zaxxer.hikari.pool.HikariProxyPreparedStatement.execute(HikariProxyPreparedStatement.java)
    at org.apache.ibatis.executor.statement.PreparedStatementHandler.update(PreparedStatementHandler.java:47)
    at org.apache.ibatis.executor.statement.RoutingStatementHandler.update(RoutingStatementHandler.java:74)
    at org.apache.ibatis.executor.SimpleExecutor.doUpdate(SimpleExecutor.java:50)
    at org.apache.ibatis.executor.BaseExecutor.update(BaseExecutor.java:117)
    at org.apache.ibatis.executor.CachingExecutor.update(CachingExecutor.java:76)
    at sun.reflect.GeneratedMethodAccessor111.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:64)
    at com.sun.proxy.$Proxy157.update(Unknown Source)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.update(DefaultSqlSession.java:194)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:427)
    at com.sun.proxy.$Proxy105.update(Unknown Source)
    at org.mybatis.spring.SqlSessionTemplate.update(SqlSessionTemplate.java:288)
    at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:67)
    at org.apache.ibatis.binding.MapperProxy$PlainMethodInvoker.invoke(MapperProxy.java:145)
    at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:86)
    at com.sun.proxy.$Proxy110.update(Unknown Source)
    at com.ecej.cc.schedule.server.service.impl.CcBaseServiceImpl.update(CcBaseServiceImpl.java:67)
    at com.ecej.cc.schedule.server.service.impl.CcDsplitServiceImpl.pullDaySplit(CcDsplitServiceImpl.java:167)
    at com.ecej.cc.schedule.server.service.impl.CcDsplitServiceImpl$$FastClassBySpringCGLIB$$8b60eee.invoke(<generated>)
    at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218)
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:771)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:367)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:118)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749)
    at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:691)
    at com.ecej.cc.schedule.server.service.impl.CcDsplitServiceImpl$$EnhancerBySpringCGLIB$$637a15b9.pullDaySplit(<generated>)
    at com.ecej.cc.schedule.job.TimingDevice.pullDaySplit(TimingDevice.java:42)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.scheduling.support.ScheduledMethodRunnable.run(ScheduledMethodRunnable.java:84)
    at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:54)
    at org.springframework.scheduling.concurrent.ReschedulingRunnable.run(ReschedulingRunnable.java:93)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run$$$capture(FutureTask.java:266)
    at java.util.concurrent.FutureTask.run(FutureTask.java)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
    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: com.mysql.cj.exceptions.CJCommunicationsException: The last packet successfully received from the server was 212,747 milliseconds ago. The last packet sent successfully to the server was 212,749 milliseconds ago. is longer than the server configured value of 'wait_timeout'. You should consider either expiring and/or testing connection validity before use in your application, increasing the server configured values for client timeouts, or using the Connector/J connection property 'autoReconnect=true' to avoid this problem.
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61)
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:105)
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:151)
    at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:167)
    at com.mysql.cj.protocol.a.NativeProtocol.readMessage(NativeProtocol.java:538)
    at com.mysql.cj.protocol.a.NativeProtocol.checkErrorMessage(NativeProtocol.java:702)
    at com.mysql.cj.protocol.a.NativeProtocol.sendCommand(NativeProtocol.java:641)
    at com.mysql.cj.protocol.a.NativeProtocol.sendCommand(NativeProtocol.java:128)
    at com.mysql.cj.NativeSession.sendCommand(NativeSession.java:311)
    at com.mysql.cj.NativeSession.queryServerVariable(NativeSession.java:1008)
    at com.mysql.cj.jdbc.ConnectionImpl.isReadOnly(ConnectionImpl.java:1406)
    ... 56 common frames omitted
Caused by: java.io.EOFException: Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.
    at com.mysql.cj.protocol.FullReadInputStream.readFully(FullReadInputStream.java:67)
    at com.mysql.cj.protocol.a.SimplePacketReader.readHeader(SimplePacketReader.java:63)
    at com.mysql.cj.protocol.a.SimplePacketReader.readHeader(SimplePacketReader.java:45)
    at com.mysql.cj.protocol.a.TimeTrackingPacketReader.readHeader(TimeTrackingPacketReader.java:52)
    at com.mysql.cj.protocol.a.TimeTrackingPacketReader.readHeader(TimeTrackingPacketReader.java:41)
    at com.mysql.cj.protocol.a.MultiPacketReader.readHeader(MultiPacketReader.java:54)
    at com.mysql.cj.protocol.a.MultiPacketReader.readHeader(MultiPacketReader.java:44)
    at com.mysql.cj.protocol.a.NativeProtocol.readMessage(NativeProtocol.java:532)
    ... 62 common frames omitted
-| [TID: N/A] | [] | [20210729 15:03:50.355] | [WARN]|[DESKTOP-OOI8H5K] | [pool-3-thread-1]|[o.s.jdbc.support.SQLErrorCodesFactory] | [--> Error while extracting database name - falling back to empty error codes] |
org.springframework.jdbc.support.MetaDataAccessException: Error while extracting DatabaseMetaData; nested exception is java.sql.SQLException: Connection is closed
    at org.springframework.jdbc.support.JdbcUtils.extractDatabaseMetaData(JdbcUtils.java:348)
    at org.springframework.jdbc.support.JdbcUtils.extractDatabaseMetaData(JdbcUtils.java:373)
    at org.springframework.jdbc.support.SQLErrorCodesFactory.getErrorCodes(SQLErrorCodesFactory.java:215)
    at org.springframework.jdbc.support.SQLErrorCodeSQLExceptionTranslator.setDataSource(SQLErrorCodeSQLExceptionTranslator.java:137)
    at org.springframework.jdbc.support.SQLErrorCodeSQLExceptionTranslator.<init>(SQLErrorCodeSQLExceptionTranslator.java:100)
    at org.mybatis.spring.MyBatisExceptionTranslator.lambda$new$0(MyBatisExceptionTranslator.java:55)
    at org.mybatis.spring.MyBatisExceptionTranslator.initExceptionTranslator(MyBatisExceptionTranslator.java:106)
    at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:88)
    at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:441)
    at com.sun.proxy.$Proxy105.update(Unknown Source)
    at org.mybatis.spring.SqlSessionTemplate.update(SqlSessionTemplate.java:288)
    at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:67)
    at org.apache.ibatis.binding.MapperProxy$PlainMethodInvoker.invoke(MapperProxy.java:145)
    at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:86)
    at com.sun.proxy.$Proxy110.update(Unknown Source)
    at com.ecej.cc.schedule.server.service.impl.CcBaseServiceImpl.update(CcBaseServiceImpl.java:67)
    at com.ecej.cc.schedule.server.service.impl.CcDsplitServiceImpl.pullDaySplit(CcDsplitServiceImpl.java:167)
    at com.ecej.cc.schedule.server.service.impl.CcDsplitServiceImpl$$FastClassBySpringCGLIB$$8b60eee.invoke(<generated>)
    at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218)
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:771)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:367)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:118)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749)
    at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:691)
    at com.ecej.cc.schedule.server.service.impl.CcDsplitServiceImpl$$EnhancerBySpringCGLIB$$637a15b9.pullDaySplit(<generated>)
    at com.ecej.cc.schedule.job.TimingDevice.pullDaySplit(TimingDevice.java:42)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.scheduling.support.ScheduledMethodRunnable.run(ScheduledMethodRunnable.java:84)
    at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:54)
    at org.springframework.scheduling.concurrent.ReschedulingRunnable.run(ReschedulingRunnable.java:93)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run$$$capture(FutureTask.java:266)
    at java.util.concurrent.FutureTask.run(FutureTask.java)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)
Caused by: java.sql.SQLException: Connection is closed
    at com.zaxxer.hikari.pool.ProxyConnection$ClosedConnection.lambda$getClosedConnection$0(ProxyConnection.java:515)
    at com.sun.proxy.$Proxy158.getMetaData(Unknown Source)
    at com.zaxxer.hikari.pool.ProxyConnection.getMetaData(ProxyConnection.java:380)
    at com.zaxxer.hikari.pool.HikariProxyConnection.getMetaData(HikariProxyConnection.java)
    at org.springframework.jdbc.support.JdbcUtils.extractDatabaseMetaData(JdbcUtils.java:337)
    ... 43 common frames omitted
-| [TID: N/A] | [] | [20210729 15:03:50.365] | [ERROR]|[DESKTOP-OOI8H5K] | [pool-3-thread-1]|[c.e.c.s.s.s.impl.CcDsplitServiceImpl] | [--> ccDsplitService pullDaySplit error e={}] |
org.springframework.dao.RecoverableDataAccessException: 
### Error updating database.  Cause: com.mysql.cj.jdbc.exceptions.CommunicationsException: The last packet successfully received from the server was 212,747 milliseconds ago. The last packet sent successfully to the server was 212,749 milliseconds ago. is longer than the server configured value of 'wait_timeout'. You should consider either expiring and/or testing connection validity before use in your application, increasing the server configured values for client timeouts, or using the Connector/J connection property 'autoReconnect=true' to avoid this problem.
### The error may exist in file [M:\ECEJ-Projects\codes\ecej-callcenter-schedule-parent\ecej-schedule-service\target\classes\mybatis\defined\CcSchedulingMapper.xml]
### The error may involve com.ecej.cc.schedule.server.mapper.CcSchedulingMapper.update-Inline
### The error occurred while setting parameters
### SQL: update               cc_scheduling              SET schecd_status=?          where         task_id=?
### Cause: com.mysql.cj.jdbc.exceptions.CommunicationsException: The last packet successfully received from the server was 212,747 milliseconds ago. The last packet sent successfully to the server was 212,749 milliseconds ago. is longer than the server configured value of 'wait_timeout'. You should consider either expiring and/or testing connection validity before use in your application, increasing the server configured values for client timeouts, or using the Connector/J connection property 'autoReconnect=true' to avoid this problem.
; The last packet successfully received from the server was 212,747 milliseconds ago. The last packet sent successfully to the server was 212,749 milliseconds ago. is longer than the server configured value of 'wait_timeout'. You should consider either expiring and/or testing connection validity before use in your application, increasing the server configured values for client timeouts, or using the Connector/J connection property 'autoReconnect=true' to avoid this problem.; nested exception is com.mysql.cj.jdbc.exceptions.CommunicationsException: The last packet successfully received from the server was 212,747 milliseconds ago. The last packet sent successfully to the server was 212,749 milliseconds ago. is longer than the server configured value of 'wait_timeout'. You should consider either expiring and/or testing connection validity before use in your application, increasing the server configured values for client timeouts, or using the Connector/J connection property 'autoReconnect=true' to avoid this problem.
    at org.springframework.jdbc.support.SQLExceptionSubclassTranslator.doTranslate(SQLExceptionSubclassTranslator.java:100)
    at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:72)
    at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:81)
    at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:91)
    at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:441)
    at com.sun.proxy.$Proxy105.update(Unknown Source)
    at org.mybatis.spring.SqlSessionTemplate.update(SqlSessionTemplate.java:288)
    at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:67)
    at org.apache.ibatis.binding.MapperProxy$PlainMethodInvoker.invoke(MapperProxy.java:145)
    at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:86)
    at com.sun.proxy.$Proxy110.update(Unknown Source)
    at com.ecej.cc.schedule.server.service.impl.CcBaseServiceImpl.update(CcBaseServiceImpl.java:67)
    at com.ecej.cc.schedule.server.service.impl.CcDsplitServiceImpl.pullDaySplit(CcDsplitServiceImpl.java:167)
    at com.ecej.cc.schedule.server.service.impl.CcDsplitServiceImpl$$FastClassBySpringCGLIB$$8b60eee.invoke(<generated>)
    at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218)
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:771)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:367)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:118)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749)
    at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:691)
    at com.ecej.cc.schedule.server.service.impl.CcDsplitServiceImpl$$EnhancerBySpringCGLIB$$637a15b9.pullDaySplit(<generated>)
    at com.ecej.cc.schedule.job.TimingDevice.pullDaySplit(TimingDevice.java:42)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.scheduling.support.ScheduledMethodRunnable.run(ScheduledMethodRunnable.java:84)
    at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:54)
    at org.springframework.scheduling.concurrent.ReschedulingRunnable.run(ReschedulingRunnable.java:93)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run$$$capture(FutureTask.java:266)
    at java.util.concurrent.FutureTask.run(FutureTask.java)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
    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: com.mysql.cj.jdbc.exceptions.CommunicationsException: The last packet successfully received from the server was 212,747 milliseconds ago. The last packet sent successfully to the server was 212,749 milliseconds ago. is longer than the server configured value of 'wait_timeout'. You should consider either expiring and/or testing connection validity before use in your application, increasing the server configured values for client timeouts, or using the Connector/J connection property 'autoReconnect=true' to avoid this problem.
    at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:174)
    at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64)
    at com.mysql.cj.jdbc.ConnectionImpl.isReadOnly(ConnectionImpl.java:1414)
    at com.mysql.cj.jdbc.ConnectionImpl.isReadOnly(ConnectionImpl.java:1399)
    at com.mysql.cj.jdbc.ClientPreparedStatement.checkReadOnlySafeStatement(ClientPreparedStatement.java:307)
    at com.mysql.cj.jdbc.ClientPreparedStatement.execute(ClientPreparedStatement.java:317)
    at com.zaxxer.hikari.pool.ProxyPreparedStatement.execute(ProxyPreparedStatement.java:44)
    at com.zaxxer.hikari.pool.HikariProxyPreparedStatement.execute(HikariProxyPreparedStatement.java)
    at org.apache.ibatis.executor.statement.PreparedStatementHandler.update(PreparedStatementHandler.java:47)
    at org.apache.ibatis.executor.statement.RoutingStatementHandler.update(RoutingStatementHandler.java:74)
    at org.apache.ibatis.executor.SimpleExecutor.doUpdate(SimpleExecutor.java:50)
    at org.apache.ibatis.executor.BaseExecutor.update(BaseExecutor.java:117)
    at org.apache.ibatis.executor.CachingExecutor.update(CachingExecutor.java:76)
    at sun.reflect.GeneratedMethodAccessor111.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:64)
    at com.sun.proxy.$Proxy157.update(Unknown Source)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.update(DefaultSqlSession.java:194)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    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:427)
    ... 35 common frames omitted
Caused by: com.mysql.cj.exceptions.CJCommunicationsException: The last packet successfully received from the server was 212,747 milliseconds ago. The last packet sent successfully to the server was 212,749 milliseconds ago. is longer than the server configured value of 'wait_timeout'. You should consider either expiring and/or testing connection validity before use in your application, increasing the server configured values for client timeouts, or using the Connector/J connection property 'autoReconnect=true' to avoid this problem.
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61)
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:105)
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:151)
    at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:167)
    at com.mysql.cj.protocol.a.NativeProtocol.readMessage(NativeProtocol.java:538)
    at com.mysql.cj.protocol.a.NativeProtocol.checkErrorMessage(NativeProtocol.java:702)
    at com.mysql.cj.protocol.a.NativeProtocol.sendCommand(NativeProtocol.java:641)
    at com.mysql.cj.protocol.a.NativeProtocol.sendCommand(NativeProtocol.java:128)
    at com.mysql.cj.NativeSession.sendCommand(NativeSession.java:311)
    at com.mysql.cj.NativeSession.queryServerVariable(NativeSession.java:1008)
    at com.mysql.cj.jdbc.ConnectionImpl.isReadOnly(ConnectionImpl.java:1406)
    ... 56 common frames omitted
Caused by: java.io.EOFException: Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.
    at com.mysql.cj.protocol.FullReadInputStream.readFully(FullReadInputStream.java:67)
    at com.mysql.cj.protocol.a.SimplePacketReader.readHeader(SimplePacketReader.java:63)
    at com.mysql.cj.protocol.a.SimplePacketReader.readHeader(SimplePacketReader.java:45)
    at com.mysql.cj.protocol.a.TimeTrackingPacketReader.readHeader(TimeTrackingPacketReader.java:52)
    at com.mysql.cj.protocol.a.TimeTrackingPacketReader.readHeader(TimeTrackingPacketReader.java:41)
    at com.mysql.cj.protocol.a.MultiPacketReader.readHeader(MultiPacketReader.java:54)
    at com.mysql.cj.protocol.a.MultiPacketReader.readHeader(MultiPacketReader.java:44)
    at com.mysql.cj.protocol.a.NativeProtocol.readMessage(NativeProtocol.java:532)
    ... 62 common frames omitted
-| [TID: N/A] | [] | [20210729 15:03:50.403] | [ERROR]|[DESKTOP-OOI8H5K] | [pool-3-thread-1]|[o.s.s.s.TaskUtils$LoggingErrorHandler] | [--> Unexpected error occurred in scheduled task] |
com.mickey.core.exception.NoveServiceException: 9999|ccDsplitService pullDaySplit exception rollback
    at com.ecej.cc.schedule.server.service.impl.CcDsplitServiceImpl.pullDaySplit(CcDsplitServiceImpl.java:180)
    at com.ecej.cc.schedule.server.service.impl.CcDsplitServiceImpl$$FastClassBySpringCGLIB$$8b60eee.invoke(<generated>)
    at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218)
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:771)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:367)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:118)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749)
    at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:691)
    at com.ecej.cc.schedule.server.service.impl.CcDsplitServiceImpl$$EnhancerBySpringCGLIB$$637a15b9.pullDaySplit(<generated>)
    at com.ecej.cc.schedule.job.TimingDevice.pullDaySplit(TimingDevice.java:42)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.scheduling.support.ScheduledMethodRunnable.run(ScheduledMethodRunnable.java:84)
    at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:54)
    at org.springframework.scheduling.concurrent.ReschedulingRunnable.run(ReschedulingRunnable.java:93)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run$$$capture(FutureTask.java:266)
    at java.util.concurrent.FutureTask.run(FutureTask.java)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
    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)

其中錯誤還會提示你修改wait_timeout或是使用Connector/J的autoReconnect屬性避免該錯誤。

後來查了一些資料，才發現遇到這個問題的人還真不少，大部分都是使用連線池方式時才會出現這個問題，短連線應該很難出現這個問題。

這個問題的原因：

　　MySQL伺服器預設的“wait_timeout”是28800秒即8小時，意味著如果一個連線的空閒時間超過8個小時，MySQL將自動斷開該連線，

　　而連線池卻認為該連線還是有效的(因為並未校驗連線的有效性)，當應用申請使用該連線時，就會導致上面的報錯。

解決方式：

1、按照錯誤的提示，可以在JDBC URL中使用autoReconnect屬性，實際測試時使用了autoReconnect=true&failOverReadOnly=false，不過並未起作用，

使用的是5.1版本，可能真像網上所說的只對4之前的版本有效。

2、沒辦法，只能修改MySQL的引數了，wait_timeout最大為31536000即1年。

在my.cnf中加入： [mysqld] wait_timeout=31536000 interactive_timeout=31536000 重啟生效，需要同時修改這兩個引數。

3、給你需要執行的邏輯重新分配一個執行緒處理，根據自身業務邏輯進行處理。