我使用 hibernate 和 spring 创建了一个简单的网络应用程序，我想实现一个包含 crud 操作的抽象类，但我有这个错误:

    org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'clientService' defined in class path resource [applicationContext.xml]: 
Cannot resolve reference to bean 'clientDao' while setting bean property 'clientDao'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: 
Error creating bean with name 'clientDao' defined in class path resource [applicationContext.xml]: 
Unsatisfied dependency expressed through constructor argument with index 0 of type [java.lang.Class]: 

通用道

public interface GenericDao<T, ID extends Serializable> {
    
    T save(T entity);
    T update(T entity);
    void delete(T entity);
    T findById(ID id);
    List<T> findAll();
    void flush();

GenericDaoImpl

@Transactional
public  class GenericDaoImpl<T, ID extends Serializable> implements GenericDao<T, ID> {
    
    @Autowired
    SessionFactory sessionFactory ;
    
 private Class<T> persistentClass;
     
     
    
    public GenericDaoImpl() {
    super();
}

    public GenericDaoImpl(Class<T> persistentClass) {
    super();
    this.persistentClass = persistentClass;
}

    @Transactional
    public T save(T entity) {
        this.sessionFactory.getCurrentSession().save(entity);
        return null;
    }

    @Transactional
    public T update(T entity) {
        this.sessionFactory.getCurrentSession().update(entity);
        return null;
    }

    @Transactional
    public void delete(T entity) {
        this.sessionFactory.getCurrentSession().delete(entity);
        
    }

    @SuppressWarnings("unchecked")
    @Transactional
    public T findById(ID id) {
        return  (T) this.sessionFactory.getCurrentSession().load(this.getPersistentClass(), id);
        
    }
    @SuppressWarnings("unchecked")
    @Transactional
    public List<T> findAll() {
        return   this.sessionFactory.getCurrentSession().createQuery("* from"+this.getPersistentClass().getSimpleName()).list();
    }

    @Transactional
    public void flush() {
        this.sessionFactory.getCurrentSession().flush();
        
    }

    public SessionFactory getSessionFactory() {
        return sessionFactory;
    }

    public void setSessionFactory(SessionFactory sessionFactory) {
        this.sessionFactory = sessionFactory;
    }

    public Class<T> getPersistentClass() {
        return persistentClass;
    }

    public void setPersistentClass(Class<T> persistentClass) {
        this.persistentClass = persistentClass;
    }
    
    

}

客户端

public interface ClientDao  extends GenericDao<Client,Integer>  {



}

ClientDaoImpl

@Transactional
@Repository("clientDao")
public class ClientDaoImpl extends GenericDaoImpl<Client,Integer>  implements ClientDao {
    
    
    

    
    
    public ClientDaoImpl(Class<Client> persistentClass) {
        super(persistentClass);
        
    }

应用程序上下文.xml

<bean id="client" class="com.webapp.model.Client"/>

  <bean id="genericDao" class="com.webapp.dao.GenericDaoImpl">
        <property name="sessionFactory" ref="sessionFactory" />
    </bean>
    <bean id="clientDao" class="com.webapp.dao.ClientDaoImpl" parent="genericDao">
    <constructor-arg ref="client" />
   </bean>

 <bean id="clientService" class="com.webapp.service.ClientServiceImpl">
        <property name="clientDao" ref="clientDao" />
    </bean>

最佳答案

使用:

<bean id="clientDao" class="com.webapp.dao.ClientDaoImpl" parent="genericDao">
<constructor-arg >com.xxx.Client</constructor-arg >

Spring 会将字符串“转换”到类中。然后您可以从 XML 中删除客户端 bean。

或者从你的ClientDaoImpl中去掉这个参数，因为它没有用(只能是这个类型，所以没有理由让它成为参数)

public ClientDaoImpl() {
    super(com.xxx.Client.class);
}

关于java - 通过索引为 0 类型 [java.lang.Class] 的构造函数参数表达的不满足依赖关系，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/17387544/