我正在尝试从spring MVC在我的控制器中注入一个dao-bean。我正在为dao-objects使用泛型dao模式。
由于未知原因,我收到此错误:
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'klantController': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private service.KlantDao controllers.KlantController.klantDao; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No matching bean of type [service.KlantDao] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
这是通用的dao界面:
package service;
import java.util.List;
public interface GenericDao<T> {
public List<T> findAll();
public T update(T object);
public T get(Long id);
public void delete(T object);
public void insert(T object);
public boolean exists(Long id) ;
}
泛型dao类:
package service;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import org.springframework.transaction.annotation.Transactional;
@Transactional
public class GenericDaoJpa<T> implements GenericDao<T> {
private Class<T> type;
private EntityManager em;
public GenericDaoJpa(Class<T> type) {
super();
this.type = type;
}
@PersistenceContext
public void setEntityManager(EntityManager em) {
this.em = em;
}
@Transactional(readOnly = true)
@Override
public T get(Long id) {
T entity = this.em.find(this.type, id);
return entity;
}
@Transactional(readOnly = true)
@Override
public List<T> findAll() {
return this.em.createQuery(
"select entity from " + this.type.getName() + " entity").getResultList();
}
//@Transactional
@Override
public void insert(T object) {
em.persist(object);
}
//@Transactional
@Override
public void delete(T object) {
em.remove(em.merge(object));
}
@Transactional(readOnly = true)
@Override
public boolean exists(Long id) {
T entity = this.em.find(this.type, id);
return entity != null;
}
@Override
public T update(T object) {
return em.merge(object);
}
}
具体的DAO我试着注入:
package service;
import domain.Klant;
public class KlantDao extends GenericDaoJpa<Klant>
{
public KlantDao()
{
super(Klant.class);
}
}
我正在尝试注入bean的控制器类:
@Controller
public class KlantController
{
@Autowired
private KlantDao klantDao;
// route methods
public KlantDao getKlantDao() {
return klantDao;
}
public void setKlantDao(KlantDao klantDao) {
this.klantDao = klantDao;
}
}
在调度程序servlet中,我像这样配置bean:
<bean id="klantDao" class="service.KlantDao"/>
我认为这个问题与自动装配有关。我尝试了很多设置组合,但总是收到同样的错误。
我希望有人可以提供帮助。 感谢
答案 0 :(得分:0)
您的代码是正确的,但您需要添加@Services KlantDao