Study in detail MyBaties in SqlSession Why do you need close

stay Mybatis There is a sentence in the document
Open one SqlSession, After returning a response , Just turn it off . This close operation is very important , In order to ensure that the close operation can be performed every time , You should put this shutdown operation in finally In block .
Mybatis file

But we know SqlSessionFactory Equivalent to a database connection pool , And by the SqlSessionFactory Got SqlSession It is equivalent to a database connection .

And when we learn about thread pools , We understand that the lifetime of threads in the thread pool is regulated by the thread pool itself , After we apply for a thread, it only works , The thread pool itself will release this thread at the most appropriate time . So as to avoid frequent application and destruction of threads .

The principle of database connection pool is similar to that of thread pool , Then why does one need to release even if one doesn't need it ?

This is mainly because when we write thread pool code , We can ’ perception ’ When the thread being used should be recycled ( Recycled when task is completed ), When a connection is used up cannot be used as a database connection pool ’ perception ’ Of , So when we finish using a connection, we need to tell the database connection pool that we have finished using , It can be recycled , The operation of notification is close. in other words SqlSession Of close It's not closing the connection , It's going to be Sqlsession Recycle into the database connection pool, that is SqlSessionFactory

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