两个类内部几乎重复的代码 [英] Two classes with almost duplicate code inside

问题描述

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

At this moment, I have two classes: UserHibernateDao and 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));
    }
}

和第二名：

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);

    }
}

我看到这两个类几乎包含相同的方法和方法实现。

I see that both classes contain almost equal methods and method implementations.

我认为，这不是很好。 你怎么看？或者这是正常的吗？

I think, it is not very good. What do you think? Or it is normal?

推荐答案

这样的事情对你有用，它通常被称为通用DAO模式。

Something like this should work for you, it's generally called the "Generic DAO Pattern".

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);
    }
}

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