Spring MVC：使用Hibernate构建泛型类型安全DAO和服务

Question

我使用Spring 3和Hibernate 4.我是这个概念的新手，并且已经做了一些阅读和学习。我找到了GenericDAO Layer和GenericService Layer的示例实现。这是我的代码：

这是AbstractDao界面：

package dao.api;


public interface IAbstractDAO<T, PK extends Serializable> {

    /** Persist the newInstance object into database */
    public PK create(T newInstance);

    /**
     * Retrieve an object that was previously persisted to the database using
     * the indicated id as primary key
     */
    public T findById(PK id);

    /**Get all Object from db */
    public List<T> listAll();

    /** Save changes made to a persistent object. */
    public void update(T transientObject);

    /** Remove an object from persistent storage in the database */
    public void delete(T persistentObject);

}

这是我的AbstractDAOImpl类：

package dao;

@Transactional
public abstract class AbstractDAOImpl<T, PK extends Serializable> implements
        IAbstractDAO<T, PK> {

    private Class<T> type;

    public AbstractDAOImpl(Class<T> type) {
        this.type = type;
    }

    @Autowired
    private SessionFactory sessionFactory;

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

    protected Session getCurrentSession() {
        // if (sessionFactory == null)
        // throw new IllegalStateException(
        // "SessionFactory has not been set on DAO before usage");
        return sessionFactory.getCurrentSession();
    }

    @SuppressWarnings("unchecked")
    @Override
    public PK create(T newInstance) {

        return (PK) getCurrentSession().save(newInstance);
    }

    @SuppressWarnings("unchecked")
    @Override
    public T findById(PK id) {

        return (T) getCurrentSession().get(type, id);
    }

    @SuppressWarnings("unchecked")
    @Override
    public List<T> listAll() {
        Criteria criteria = getCurrentSession().createCriteria(type);
        return criteria.list();
    }

    @Override
    public void update(T transientObject) {
        getCurrentSession().update(transientObject);

    }

    @Override
    public void delete(T persistentObject) {
        getCurrentSession().delete(persistentObject);

    }

}

这是我的IUserDAO界面：

package dao.api;


public interface IUserDAO extends IAbstractDAO<User,Integer> {

}

这是我的UserDAOImpl类：

package tma.com.ntrungnghia.dao;


import org.springframework.stereotype.Repository;

import tma.com.ntrungnghia.dao.api.IUserDAO;
import tma.com.ntrungnghia.domain.User;

@Repository("userDAO")
public class UserDAOImpl extends AbstractDAOImpl<User, Integer> implements IUserDAO{

    public UserDAOImpl() {
        super(User.class);
    }


}

在服务层，我有IAbstractService接口

package service.api;


public interface IAbstractService<T, PK extends Serializable > {

    /** Persist the newInstance object into database */
    public PK create(T newInstance);

    /**
     * Retrieve an object that was previously persisted to the database using
     * the indicated id as primary key
     */
    public T findById(PK id);

    /**Get all Object from db */
    public List<T> listAll();

    /** Save changes made to a persistent object. */
    public void update(T transientObject);

    /** Remove an object from persistent storage in the database */
    public void delete(T persistentObject);

}

这是AbstractServiceImpl类：

package service;

import java.io.Serializable;
import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;

import tma.com.ntrungnghia.dao.api.IAbstractDAO;
import tma.com.ntrungnghia.service.api.IAbstractService;

public abstract class AbstractServiceImpl<T,PK extends Serializable> implements IAbstractService<T, PK> {

    @Autowired
    protected IAbstractDAO<T, PK> dao;

    @Override
    public PK create(T newInstance) {

        return dao.create(newInstance);
    }

    @Override
    public T findById(PK id) {
        // TODO Auto-generated method stub
        return dao.findById(id);
    }

    @Override
    public List<T> listAll() {
        // TODO Auto-generated method stub
        return dao.listAll();
    }

    @Override
    public void update(T transientObject) {
        dao.update(transientObject);

    }

    @Override
    public void delete(T persistentObject) {
        dao.delete(persistentObject);
    }

}

这是我的IUserService接口：

package service.api;



public interface IUserService extends IAbstractService<User, Integer>{

}

和UserService接口的实现：

package service;


@Service("userService")
public class UserServiceImpl extends AbstractServiceImpl<User, Integer> implements IUserService{

}

这是我的控制器：

@Controller
public class HomeController {

    @Autowired
    IUserService userService;

    @Autowired
    IOrderService orderService;

    @Autowired
    IOrderDeitalService orderDeitalService;

    @Autowired
    IAlbumService albumService;

    @Autowired
    IGenreService genreService;

    @Autowired
    IArtistService artistService;



    private static final Logger logger = LoggerFactory.getLogger(HomeController.class);

    /**
     * Simply selects the home view to render by returning its name.
     */
    @RequestMapping(value = "/", method = RequestMethod.GET)
    public String home(Locale locale, Model model) {
        logger.info("Welcome home! The client locale is {}.", locale);

        Date date = new Date();
        DateFormat dateFormat = DateFormat.getDateTimeInstance(DateFormat.LONG, DateFormat.LONG, locale);

        String formattedDate = dateFormat.format(date);

        model.addAttribute("serverTime", formattedDate );

        User u = new User();
        userService.create(u);


        return "home";
    }

}

Spring配置文件：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:tx="http://www.springframework.org/schema/tx" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context-3.1.xsd
    http://www.springframework.org/schema/tx
    http://www.springframework.org/schema/tx/spring-tx-3.1.xsd">
    <!-- Root Context: defines shared resources visible to all other web components -->

    <bean id="dataSource"
        class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="url" value="jdbc:mysql://localhost:3306/musicstore"></property>
        <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
        <property name="username" value="root"></property>
        <property name="password" value="123456"></property>
    </bean>


    <bean id="sessionFactory" name="sessionFactory"
        class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
        <property name="dataSource" ref="dataSource"></property>
        <property name="hibernateProperties">
            <props>
                <prop key="hibernate.dialect"> org.hibernate.dialect.MySQLDialect </prop>
                <prop key="hibernate.max_fetch_depth">3</prop>
                <prop key="hibernate.jdbc.fetch_size">50</prop>
                <prop key="hibernate.jdbc.batch_size">10</prop>
                <prop key="hibernate.show_sql">true</prop>
            </props>
        </property>
        <property name="packagesToScan" value="domain" /><!-- entity -->
    </bean>


    <bean id="transactionManager"
        class="org.springframework.orm.hibernate4.HibernateTransactionManager">
        <property name="sessionFactory" ref="sessionFactory" />
        <property name="dataSource" ref="dataSource" />
    </bean>

    <context:component-scan base-package="dao" />
    <context:component-scan base-package="service" />

    <tx:annotation-driven transaction-manager="transactionManager" />


</beans>

这是我运行项目时得到的结果

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'albumService': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: protected tma.com.ntrungnghia.dao.api.IAbstractDAO tma.com.ntrungnghia.service.AbstractServiceImpl.dao; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No unique bean of type [tma.com.ntrungnghia.dao.api.IAbstractDAO] is defined: expected single matching bean but found 6: [albumDAO, artistDAO, genreDAO, orderDAO, orderDetailDAO, userDAO]
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:287)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1106)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:517)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:294)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:225)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:291)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:585)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:913)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:464)
    at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:385)
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:284)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:111)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4973)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5467)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:632)
    at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:670)
    at org.apache.catalina.startup.HostConfig$DeployDescriptor.run(HostConfig.java:1839)
    at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
    at java.util.concurrent.FutureTask.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: protected tma.com.ntrungnghia.dao.api.IAbstractDAO tma.com.ntrungnghia.service.AbstractServiceImpl.dao; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No unique bean of type [tma.com.ntrungnghia.dao.api.IAbstractDAO] is defined: expected single matching bean but found 6: [albumDAO, artistDAO, genreDAO, orderDAO, orderDetailDAO, userDAO]
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:506)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:284)
    ... 26 more
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No unique bean of type [tma.com.ntrungnghia.dao.api.IAbstractDAO] is defined: expected single matching bean but found 6: [albumDAO, artistDAO, genreDAO, orderDAO, orderDetailDAO, userDAO]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:800)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:707)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:478)
    ... 28 more
Oct 08, 2014 4:41:34 PM org.apache.catalina.core.StandardContext listenerStart
SEVERE: Exception sending context initialized event to listener instance of class org.springframework.web.context.ContextLoaderListener
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'albumService': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: protected tma.com.ntrungnghia.dao.api.IAbstractDAO tma.com.ntrungnghia.service.AbstractServiceImpl.dao; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No unique bean of type [tma.com.ntrungnghia.dao.api.IAbstractDAO] is defined: expected single matching bean but found 6: [albumDAO, artistDAO, genreDAO, orderDAO, orderDetailDAO, userDAO]
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:287)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1106)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:517)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:294)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:225)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:291)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:585)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:913)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:464)
    at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:385)
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:284)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:111)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4973)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5467)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:632)
    at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:670)
    at org.apache.catalina.startup.HostConfig$DeployDescriptor.run(HostConfig.java:1839)
    at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
    at java.util.concurrent.FutureTask.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: protected tma.com.ntrungnghia.dao.api.IAbstractDAO tma.com.ntrungnghia.service.AbstractServiceImpl.dao; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No unique bean of type [tma.com.ntrungnghia.dao.api.IAbstractDAO] is defined: expected single matching bean but found 6: [albumDAO, artistDAO, genreDAO, orderDAO, orderDetailDAO, userDAO]
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:506)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:284)
    ... 26 more
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No unique bean of type [tma.com.ntrungnghia.dao.api.IAbstractDAO] is defined: expected single matching bean but found 6: [albumDAO, artistDAO, genreDAO, orderDAO, orderDetailDAO, userDAO]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:800)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:707)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:478)
    ... 28 more

我对albumDAO，artistDAO，genreDAO，orderDAO，orderDetailDAO和这些服务做了同样的事情。

当我使用AbstractService中定义的create方法时，它不起作用。我不明白。如果有人可以帮助我？

提前感谢您的想法和回应！