when a client accesses a resource that can turn on a session, the Web server creates a HttpSession object, each HttpSession object consumes a certain amount of memory and consumes a lot of server memory if there are too many users in the same time period. To solve this problem we use a technique:
session persistence.
What is the persistence of the session? The Web server transfers temporarily inactive and non-defunct HttpSession objects to the file system or database for storage, and the server takes them to memory. It is necessary to use serialization to transfer the session object to the file system or database, and
java. Io. Serializable. a passivation operation is performed at the time of the Tomcat reboot, and the activation is activated after the boot succeeds. loading in the corresponding area is not lost (provided that the variables stored in the session must implement the serialization interface to be passivated,can be serialized to a binary file on the hard disk).
Why entity classes need to be serialized in Java
