The different scopes and life cycle categories are critical because the wrong use can cause serious concurrency problems. The SqlSessionFactoryBuilder is:
- This class can be instantiated, used, and discarded; once the SqlSessionFactory has been created, it is no longer needed.
- A local variable
SqlSessionFactory:
- In plain English, you can think of it as: database connection pooling
- Once created, the SqlSessionFactory should exist for the duration of the application, and there is no reason to discard it or recreate another instance.
- So the best scope for SqlSessionFactory is the application scope.
- The simplest is to use singletons or static singletons.
SqlSession:
- A request to connect to the connection pool
- Instances of a SQLSession are not thread-safe and therefore cannot be shared, so its optimal scope is the request or method scope.
- Must be closed after use, otherwise cause a large memory resource overhead!
Every mapper here represents every specific business!
