EclipseLink（JPA 2）缺少描述符異常

Question

我在使用Netbeans 6.9.1中的EclipseLink（JPA 2）時遇到了問題，針對Oracle 11g。我不斷收到試圖運行原生查詢時出現以下錯誤：

Exception Description: Missing descriptor for [class Novartis.OTM.Data.Db.Entities.Lookup]. 
Query: ReadAllQuery(referenceClass=Lookup sql="SELECT l FROM lookup l WHERE l.lookup_type = :LookupType AND domain = :Domain") 

他是代碼：

public List<SelectItem> getLookupForUI(enumLookupType lookupType, String domain) throws Exception { 
    if (domain == null || domain.trim().equals("")) 
     throw new Exception("Parameter domain cannot be null or empty."); 
    else if (!this.isInitialized()) 
     throw new Exception("Entity Manager not set."); 

    Query query = this._EM.createNativeQuery(_QueryGetLookupForUI, Lookup.class); 
    query.setParameter("LookupType", lookupType.toString()); 
    query.setParameter("Domain", domain.trim()); 

    List<SelectItem> selectItems = null; 

    List<Lookup> lookupList = (List<Lookup>) query.getResultList(); 
    if (lookupList == null || lookupList.size() < 1) 
     return null; 
    else { 
     selectItems = new ArrayList<SelectItem>(lookupList.size()); 
     for (Lookup lookUp : lookupList) { 
      selectItems.add(new SelectItem(lookUp.getLookupValue(), lookUp.getLookupName())); 
     } 
    } 

    return selectItems; 
} 

儘管檢查我有一個有效的實體類，我不知道這是爲什麼失敗。預先感謝您的幫助。

克里斯

Answer 1

也許嘗試：

SELECT l FROM Lookup代替SELECT l FROM lookup？