package cn.itcast.oa.base;

import java.util.List;

public interface BaseDao<T> {

    void save(T entity);

    void delete(Long id);

    void update(T entity);

    T getById(Long id);

    List<T> getByIds(Long[] ids);

    List<T> findAll();

}

package cn.itcast.oa.base;

import java.lang.reflect.ParameterizedType;

import java.util.Collections;

import java.util.List;

import javax.annotation.Resource;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

@SuppressWarnings("unchecked")

public abstract class BaseDaoImpl<T> implements BaseDao<T> {

    @Resource

    private SessionFactory sessionFactory;

    protected Class<T> clazz; 

    public BaseDaoImpl() {

        // 通过反射得到T的真实类型 【0】数组是因为有可能 不只一个T

        ParameterizedType pt = (ParameterizedType) this.getClass().getGenericSuperclass();

        this.clazz = (Class) pt.getActualTypeArguments()[];

        System.out.println("clazz = " + clazz.getName());

    }

    public void save(T entity) {

        getSession().save(entity);

    }

    public void update(T entity) {

        getSession().update(entity);

    }

    public void delete(Long id) {

        Object obj = getSession().get(clazz, id);

        getSession().delete(obj);

    }

    public T getById(Long id) {

        return (T) getSession().get(clazz, id);

    }

    public List<T> getByIds(Long[] ids) {

        if (ids == null || ids.length == ) {

            return Collections.EMPTY_LIST;

        }

        return getSession().createQuery(//

                "FROM " + clazz.getSimpleName() + " WHERE id IN(:ids)")//

                .setParameterList("ids", ids)//

                .list();

    }

    public List<T> findAll() {

        return getSession().createQuery(//

                "FROM " + clazz.getSimpleName())//

                .list();

    }

    /**

     * 获取当前可用的Session

     *

     * @return

     */

    protected Session getSession() {

        return sessionFactory.getCurrentSession();

    }

}

package cn.itcast.oa.dao;

import cn.itcast.oa.base.BaseDao;

import cn.itcast.oa.domain.Role;

public interface RoleDao extends BaseDao<Role>{

}

package cn.itcast.oa.dao;

import cn.itcast.oa.base.BaseDao;

import cn.itcast.oa.domain.User;

public interface UserDao extends BaseDao<User> {

}

package cn.itcast.oa.dao.impl;

import org.springframework.stereotype.Repository;

import cn.itcast.oa.base.BaseDaoImpl;

import cn.itcast.oa.dao.RoleDao;

import cn.itcast.oa.domain.Role;

@Repository

public class RoleDaoImpl extends BaseDaoImpl<Role> implements RoleDao {

    // public RoleDaoImpl(){

    // clazz = Role.class;

    // }

}

package cn.itcast.oa.dao.impl;

import org.springframework.stereotype.Repository;

import cn.itcast.oa.base.BaseDaoImpl;

import cn.itcast.oa.dao.UserDao;

import cn.itcast.oa.domain.User;

@Repository

public class UserDaoImpl extends BaseDaoImpl<User> implements UserDao {

    // public UserDaoImpl(){

    // clazz = User.class;

    // }

}