1.用户可以登录注册 2.高级权限的用户可以发报黑板报,板报除了基本的属性以外还需要有:生效时间,失效时间,发布者 3.所有用户登录后的主页面都显示当前处理有效时间范围内的板报(在生效时间到失效时间之间）。-User can login registered 2 senior privileges transmitters to Blackboard blackboard newspaper is also needed in addition to the basic proper