Returns the object bound to the associated session identified by the specified attribute key. If there
is no object bound under the attribute key for the given session, {@code null} is returned.
@param sessionKey session key to use to look up the target session.
@param attributeKey the unique name of the object bound to the associated session
@return the object bound under the {@code attributeKey} or {@code null} if there is no object bound.
@throws InvalidSessionException if the specified session has stopped or expired prior to calling this method.
@see hunt.shiro.session.Session#getAttribute(Object key)
Returns the object bound to the associated session identified by the specified attribute key. If there is no object bound under the attribute key for the given session, {@code null} is returned.
@param sessionKey session key to use to look up the target session. @param attributeKey the unique name of the object bound to the associated session @return the object bound under the {@code attributeKey} or {@code null} if there is no object bound. @throws InvalidSessionException if the specified session has stopped or expired prior to calling this method. @see hunt.shiro.session.Session#getAttribute(Object key)