泛型错误 - 找不到符号类

Question

这是我的第一个问题。我是初学者:-)

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; 
    } 

} 

当我做编译，我得到错误：

cannot find symbol class CrudDAO 

怎么了？

Answer 1

这两个类来自不同的包吗？如果他们是，你是否进口CrudDAO？

如果它们在同一个包中，请提供有关编译器错误的更多详细信息。