泛型錯誤 - 找不到符號類

Question

這是我的第一個問題。我是初學者:-)

我有通用的DAO（CrudDao）：

public class CrudDAO<T> { 

    @PersistenceContext 
    protected EntityManager em; 

    private Class<T> classePersistencia; 

    public CrudDAO() { 
    this.setClassePersistencia((Class<T>) ((ParameterizedType) 
     getClass().getGenericSuperclass()).getActualTypeArguments()[0]); 
    } 

    public T salvar(T entity) { 
    em.persist(entity); 
    return entity; 
    } 

    public T alterar(T entity) { 
    return em.merge(entity); 
    } 

    public void excluir(T entity) { 
    em.remove(entity); 
    } 

    public T buscarPorId(Long id) { 
    return (T) em.find(getClassePersistencia(), id); 
    } 

    public List<T> buscarTodos(){ 
    return em.createQuery("from " + getClassePersistencia().getName()).getResultList(); 
    } 

    /*Getter e Setter*/ 

    public Class<T> getClassePersistencia() { 
    return classePersistencia; 
    } 

    public void setClassePersistencia(Class<T> classePersistencia) { 
    this.classePersistencia = classePersistencia; 
    } 
} 

，我有DiasService

public class DiasService extends CrudDAO<Dias> implements IdiasService { 

    @Transactional(readOnly = true) 
    public Dias buscaPorId(Long id) { 
    return (Dias) super.buscarPorId(id); 
    } 

    @Transactional(readOnly = false) 
    public Dias salvar(Dias dia) { 
    return (Dias) super.salvar(dia); 
    } 

    @Transactional(readOnly = false) 
    public Dias alterar(Dias dia) { 
    return (Dias) super.alterar(dia); 
    } 

    @Transactional(readOnly = false) 
    public void excluir(Dias dia) { 
    super.excluir(dia); 
    } 

    @Transactional(readOnly = true) 
    public List<Dias> buscaPorPeriodo(Date inicio, Date fim) { 
    return null; 
    } 

    @Transactional(readOnly = false) 
    public List<Dias> buscaTodos() { 
    return super.buscarTodos(); 
    } 

    @Transactional(readOnly = true) 
    public Dias buscaPorData(Date data) { 
    return null; 
    } 

} 

當我做編譯，我得到錯誤：

cannot find symbol class CrudDAO 

怎麼了？

Answer 1

這兩個類來自不同的包嗎？如果他們是，你是否進口CrudDAO？

如果它們在同一個包中，請提供有關編譯器錯誤的更多詳細信息。