Threadlocal in hibernate

I learned about hibernate today and saw the data connection section. I saw a threadlocal class and read these two articles online. Article.
Http://qszhuang.blogchina.com/blog/article_20407.72483.html
Http://www-900.ibm.com/developerWorks/cn/java/j-threads/index3.shtml#h5450
Threadlocal is used to implement a local variable of the thread. A local variable of the thread means that every instance of the thread will own an instance of this variable. all instances of the thread will not share this variable, or this variable is independent for each instance of the thread. In this way, there is no synchronization problem for such a variable, but it cannot be shared with the thread and cannot be used for communication between threads.
In hibernate, net. SF. hibernate. session is such a variable. servlet creates a thread for each client. That is to say, each client has a net. SF. hibernate. session instance. Net. SF. hibernate. Session corresponds to a session connected to the database. A session corresponds to a connection to the database (you cannot determine it. Check the hibernate source code tomorrow). That is to say, every client in hibernate has a connection to the database.