类 HttpSessionMutexListener

public class HttpSessionMutexListener
extends Object
implements HttpSessionListener

Servlet HttpSessionListener that automatically exposes the session mutex when an HttpSession gets created. To be registered as a listener in web.xml.

The session mutex is guaranteed to be the same object during the entire lifetime of the session, available under the key defined by the SESSION_MUTEX_ATTRIBUTE constant. It serves as a safe reference to synchronize on for locking on the current session.

In many cases, the HttpSession reference itself is a safe mutex as well, since it will always be the same object reference for the same active logical session. However, this is not guaranteed across different servlet containers; the only 100% safe way is a session mutex.