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        ParameterizedType pt = (ParameterizedType) this.getClass().getGenericSuperclass();        this.clazz = (Class) pt.getActualTypeArguments()[0];        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 == 0) {            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;@Repositorypublic 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;@Repositorypublic class UserDaoImpl extends BaseDaoImpl<User> implements UserDao {    // public UserDaoImpl(){    // clazz = User.class;    // }}