當我在JPA中進行編碼時，查詢

Question

類型的getLong（）方法未定義，我發現此錯誤說「方法getLong（）未定義類型Query」，請幫我解決此問題。

public long getErrorid(String errDesc) 
{long errorid=0; 
EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("wqs-poc"); System.out.println("EntityManager Factory created successfully !!!"); 
    EntityManager em = entityManagerFactory.createEntityManager(); 
    System.out.println("eNTITYmANAGER CREATED SUCCESSFLLY !!!"); Query query = em.createNativeQuery("SELECT errorid FROM wqsd.error_master WHERE errdsesc = "+errorid); errorid = (long)query.getLong(); 
    System.out.println("errorid= "+errorid); 
    return errorid;} 

Answer 1

錯誤是告訴你getLong（）沒有爲javax.persistence.Query接口定義。也許你的意思是：

errorid = (Long)query.getSingleResult()[0];