今天學習了青鳥租房管理系統，出現了下面的錯誤，百度找了半天，沒法，大神救我！??！嚴重: Servlet.service() for servlet jsp threw exceptiontag 'doubleselect', field 'list', name 'districtId': The requested list key 'disList' could not be resolved as a collection/array/map/enumeration/iterator type. Example: people or people.{name} - [unknown location]嚴重: Servlet.service() for servlet [jsp] in context with path [/RentHouse] threw exception [tag 'doubleselect', field 'list', name 'districtId': The requested list key 'disList' could not be resolved as a collection/array/map/enumeration/iterator type. Example: people or people.{name} - [unknown location]] with root causetag 'doubleselect', field 'list', name 'districtId': The requested list key 'disList' could not be resolved as a collection/array/map/enumeration/iterator type. Example: people or people.{name} - [unknown location]