ConflictStrategy

如果已经存在相同 key 的值且其仍处于活跃状态， 抛出异常 ConflictSessionKeyException。

关闭旧的现存值，并用提供的新值取代。

直接返回旧的现存值，忽略新值

Returns a representation of an immutable list of all enum entries, in the order they're declared.

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Returns an array containing the constants of this enum type, in the order they're declared.