Unexpected exception when MySQL sessions reconnected.

[doublesong]

Mybaits version： 2.0.1
MySQL connector version： 8.0.20
**JDBC URL：**jdbc:mysql://io:port/dbname?user=xxx&password=xxx&autoReconnect=ture

When the connection is disconnected and reconnected automatically,we will get unexpected exception：ConnectionImpl.commit, throw exception: Can't call commit when autocommit=true

The stack information is as follows:

ConnectionImpl.commit called, print stackTrace: 
 com.mysql.cj.jdbc.ConnectionImpl.commit(ConnectionImpl.java:773)
 sun.reflect.GeneratedMethodAccessor839.invoke(Unknown Source)
 sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
 java.lang.reflect.Method.invoke(Method.java:498)
 org.apache.tomcat.jdbc.pool.ProxyConnection.invoke(ProxyConnection.java:131)
 org.apache.tomcat.jdbc.pool.JdbcInterceptor.invoke(JdbcInterceptor.java:109)
 org.apache.tomcat.jdbc.pool.interceptor.AbstractCreateStatementInterceptor.invoke(AbstractCreateStatementInterceptor.java:79)
 org.apache.tomcat.jdbc.pool.JdbcInterceptor.invoke(JdbcInterceptor.java:109)
 org.apache.tomcat.jdbc.pool.interceptor.AbstractCreateStatementInterceptor.invoke(AbstractCreateStatementInterceptor.java:79)
 org.apache.tomcat.jdbc.pool.JdbcInterceptor.invoke(JdbcInterceptor.java:109)
 org.apache.tomcat.jdbc.pool.interceptor.ConnectionState.invoke(ConnectionState.java:158)
 org.apache.tomcat.jdbc.pool.JdbcInterceptor.invoke(JdbcInterceptor.java:109)
 org.apache.tomcat.jdbc.pool.TrapException.invoke(TrapException.java:39)
 org.apache.tomcat.jdbc.pool.JdbcInterceptor.invoke(JdbcInterceptor.java:109)
 org.apache.tomcat.jdbc.pool.interceptor.AbstractCreateStatementInterceptor.invoke(AbstractCreateStatementInterceptor.java:79)
 org.apache.tomcat.jdbc.pool.JdbcInterceptor.invoke(JdbcInterceptor.java:109)
 org.apache.tomcat.jdbc.pool.DisposableConnectionFacade.invoke(DisposableConnectionFacade.java:81)
 com.sun.proxy.$Proxy137.commit(Unknown Source)
 org.mybatis.spring.transaction.SpringManagedTransaction.commit(SpringManagedTransaction.java:101)
 org.apache.ibatis.executor.BaseExecutor.commit(BaseExecutor.java:244)
 org.apache.ibatis.executor.CachingExecutor.commit(CachingExecutor.java:119)
 org.apache.ibatis.session.defaults.DefaultSqlSession.commit(DefaultSqlSession.java:223)
 org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(**SqlSessionTemplate.java:437**)
 com.sun.proxy.$Proxy138.selectList(Unknown Source)
 org.mybatis.spring.SqlSessionTemplate.selectList(SqlSessionTemplate.java:230)
 com.baomidou.mybatisplus.core.override.MybatisMapperMethod.executeForMany(MybatisMapperMethod.java:158)
 com.baomidou.mybatisplus.core.override.MybatisMapperMethod.execute(MybatisMapperMethod.java:76)
 com.baomidou.mybatisplus.core.override.MybatisMapperProxy.invoke(MybatisMapperProxy.java:62)
 com.sun.proxy.$Proxy184.findByReveAr(Unknown Source)
 com.xxx.xxxx.xx.xxx.dao.xxx.xxx(xxx.java:188)

To avoid this Unexpected exception,We suggets check the connection status before sqlSession.commit method.

 SqlSessionTemplate.java:437
 if (!isSqlSessionTransactional(sqlSession, SqlSessionTemplate.this.sqlSessionFactory)) {
          // force commit even on non-dirty sessions because some databases require
          // a commit/rollback before calling close()
          sqlSession.commit(true);
        }

[liwei225]

Guess it might be due to TransactionSynchronizationManager.unbindResource method deregister the session created by auto_reconnect from TransactionManager(is it related to #18 ？ )

but the new session reuse old session structure ,is still live in connection pool and isautocommit=true

then mybatis get this session and execute some sql , isSqlSessionTransactional function evaluates this session doesn't belong to spring TransactionManager.
so mybatis run sqlSession.commit method cause this exception

[doublesong]

Here is SpringTransactionManagerTest's test case. Maybe the exception is original expectations