Different scopes and lifecycle categories are crucial because incorrect use can lead to very serious concurrency problems.
- This class can be instantiated, used, and discarded. Once sqlsessionfactory is created, it is no longer needed.
- local variable
- To put it bluntly, it can be imagined as: database connection pool
- Once sqlsessionfactory is created, it should always exist during the running of the application,There is no reason to discard it or recreate another instance.
- Therefore, the best scope of sqlsessionfactory is the application scope.
- The simplest is to use singleton mode or static singleton mode.
- A request to connect to the connection pool
- The instance of sqlsession is not thread safe, so it cannot be shared, so its best scope is the request or method scope.
- It must be closed after use, otherwise it will cause great memory resource overhead!
Every mapper here represents every specific business!