Spring XML配置到JavaConfig：继承和Bean依赖

Question

I have a list of services that extend an AbstractService class. The AbstractService holds the DAO (you can call it "repository") and has the getter/setter for the DAO:

/**
 * @param <T> Entity type
 * @param <K> Entity ID type
 * @param <S> DAO type
 */
public abstract class AbstractService<T, K extends Serializable, S extends BaseDAO<T, K>> implements BaseService<T, K> {
    private S dao;

    public S getDAO() { return dao; }

    public void setDAO(S dao) { this.dao = dao; }

    // Then common methods to all my services, using the DAO, for instance

    @Override
    public Optional<T> findOne(K key) throws DataException {
        return Optional.ofNullable(dao.findOne(key));
    }
}

A service example:

@Service
public class EmployeeServiceImpl extends AbstractService<Employee, Integer, EmployeeDAO> implements EmployeeService {
    // Some specific methods to that service
}

The related DAO (I use Spring Data JPA):

public interface EmployeeDAO extends BaseDAO<Employee, Integer> {
}

Extending

@NoRepositoryBean
public interface BaseDAO<T, K extends Serializable> extends JpaRepository<T, K> {
}

By the way I added the annotations @Service and @NoRepositoryBean while moving to JavaConfig.
My old XML config was:

<bean id="com.xxx.service._AbstractService" abstract="true" class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean">
    <property name="transactionManager" ref="com.xxx.dao._TxManager" />
    <property name="transactionAttributes">
        <props>
            <prop key="save*">PROPAGATION_REQUIRED,-com.xxx.DataException</prop>
            <prop key="update*">PROPAGATION_REQUIRED,-com.xxx.DataException</prop>
            <prop key="delete*">PROPAGATION_REQUIRED,-com.xxx.DataException</prop>
        </props>
    </property>
</bean>

<bean id="com.xxx.service.EmployeeService" parent="com.xxx.service._AbstractBO">
    <property name="target">
        <bean class="com.xxx.service.EmployeeServiceImpl">
            <property name="DAO" ref="com.xxx.dao.EmployeeDAO"/>
        </bean>
    </property>
</bean>

First question, what is the proper way to inject the generic DAO and handle the service inheritance using JavaConfig?
Second question, how to translate the XML snippet about transactions (com.xxx.service._AbstractBO) to JavaConfig?

Here is what I have so far, 2 classes:

@Configuration
@ComponentScan("com.xxx.service")
public class SpringConfig {
}

And the persistence config

@Configuration
@EnableJpaRepositories("com.xxx.repository")
@EnableTransactionManagement
public class PersistenceConfig {
    /* Here so far I defined the DataSource, the EntityManagerFactory,
       the PlatformTransactionManager and the JpaVendorAdapter */
}

Thanks in advance for your time!

Answer 1

Here is what I ended up doing: instead of trying to translate my old XML config, I changed the classes design. Since DAOs are required anyway, I inject them in each concrete class constructor which calls a new abstract class constructor I added.

The abstract service:

final private S dao;

public AbstractService(S dao) {
    super();
    this.dao = dao;
}

// getter protected and setter removed
protected S getDAO() {
    return dao;
}

And a concrete service example:

@Service
public class EmployeeServiceImpl extends AbstractService<Employee, Integer, EmployeeDAO> implements EmployeeService {

    @Inject
    public EmployeeServiceImpl(EmployeeDAO dao) {
        super(dao);
    }
}

The good thing is I didn't have to change the Java config I posted in my question, meaning @EnableJpaRepositories("com.xxx.repository") and @ComponentScan("com.xxx.service") are sufficient to generate and bind beans.