Autowired required a single bean, but 2 were found

1. 自定注入失敗 發現兩個對象 不能確定注入哪一個
2. 解決辦法：使用@Qualifier(“XXX”)註解
   @Qualifier(“XXX”) 中的 XX是 Bean 的名稱，所以 @Autowired 和 @Qualifier 結合使用時，自動注入的策略就從 byType 轉變成 byName 了。
4. 日誌

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APPLICATION FAILED TO START
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Description:

Field iOnlineUserService in com.after90s.frame.shiro.session.OnlineSessionDAO required a single bean, but 2 were found:
	- userOnlineService: defined in file [D:\workspace-sts\GeneralBackend\target\classes\com\after90s\core\monitor\online\service\OnlineUserServiceImpl.class]
	- IOnlineUserService: defined in file [D:\workspace-sts\GeneralBackend\target\classes\com\after90s\core\monitor\online\service\IOnlineUserService.class]


Action:

Consider marking one of the beans as @Primary, updating the consumer to accept multiple beans, or using @Qualifier to identify the bean that should be consumed