两个类内部几乎重复的代码

Question

此刻,我有两个课程:UserHibernateDao和TicketHibernateDao:

import java.util.List;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;

import model.dao.Dao;
import model.entity.User;

public class UserDaoHibernate extends HibernateDaoSupport implements Dao<User> {

    public User get(long id) {
        return getHibernateTemplate().get(User.class, id);
    }

    public void save(User user) {
        getHibernateTemplate().save(user);

    }

    public void remove(long id) {
        getHibernateTemplate().delete(
                getHibernateTemplate().get(User.class, id));
    }
}

第二个:

import java.util.List;

import org.springframework.orm.hibernate3.support.HibernateDaoSupport;

import model.dao.Dao;
import model.entity.Ticket;

public class TicketDaoHibernate extends HibernateDaoSupport implements
        Dao<Ticket> {

    public Ticket get(long id) {

        return getHibernateTemplate().get(Ticket.class, id);

    }

    public void save(Ticket ticket) {
        getHibernateTemplate().save(ticket);
    }

    public void remove(long id) {

        getHibernateTemplate().delete(
                getHibernateTemplate().get(Ticket.class, id));

    }

    public void save(Ticket ticket) {

        getHibernateTemplate().saveOrUpdate(ticket);

    }
}

我看到这两个类包含几乎相同的方法和方法实现.

我想,这不是很好.你怎么看？还是很正常的？

Answer 1

这样的东西应该适合你,它通常被称为"通用DAO模式".

public abstract class BaseDaoHibernate<T> extends HibernateDaoSupport implements Dao<T> {

    private final Class<T> entityType;

    protected BaseDaoHibernate(Class<T> entityType) {
        this.entityType = entityType;
    }

    public T get(long id) {
        return getHibernateTemplate().get(entityType, id);
    }

    public void save(T entity) {
        getHibernateTemplate().save(entity);
    }

    public void remove(long id) {
        getHibernateTemplate().delete(get(id));
    }
}

然后:

public class TicketDaoHibernate extends BaseDaoHibernate<Ticket> {
    public TicketDaoHibernate() {
        super(Ticket.class);
    }
}

和

public class UserDaoHibernate extends BaseDaoHibernate<User> {
    public UserDaoHibernate() {
        super(User.class);
    }
}