二 Hibernate 改写学生管理系统的业务功能

public class StudentDaoImpl implements StudentDao {

    @Override
    /**
     * 查询所有学生
     *
     * @throws SQLException
     */
    public List<Student> findAll() throws SQLException {
        Session session = HibernateUtils.oppenSession();
        Transaction transaction = session.beginTransaction();
        // HQL查询,面向对象的查询语言，from Student
        Query query = session.createQuery("from Student");
        List<Student> list = query.list();
        transaction.commit();
        session.close();
        return list;
    }

    @Override
    /**
     * 需要添加到数据库的学生
     */
    public void insert(Student student) throws SQLException {
        Session session = HibernateUtils.oppenSession();
        Transaction transaction = session.beginTransaction();
        // HQL查询,面向对象的查询语言
        session.save(student);
        transaction.commit();
        session.close();
    }

    @Override
    /**
     * 根据id删除学生
     */
    public void delete(int sid) throws SQLException {
        Session session = HibernateUtils.oppenSession();
        Transaction transaction = session.beginTransaction();
        // HQL查询,面向对象的查询语言
        Student student = session.get(Student.class, sid);
        session.delete(student);
        transaction.commit();
        session.close();
    }

    /**
     * 根据id查询单个学生
     *
     * @throws SQLException
     */
    @Override
    public Student findStudentById(int sid) throws SQLException {

        Session session = HibernateUtils.oppenSession();
        Transaction transaction = session.beginTransaction();
        // HQL查询,面向对象的查询语言
        Student student = session.get(Student.class, sid);
        transaction.commit();
        session.close();
        return student;
    }

    @Override
    /**
     * 更新学生到数据库
     */
    public void Update(Student stu, int sid) throws SQLException {

        Session session = HibernateUtils.oppenSession();
        Transaction transaction = session.beginTransaction();
        stu.setSid(sid);
        session.saveOrUpdate(stu);
        transaction.commit();
        session.close();
    }

    @Override
    /**
     * 模糊查询的DAO层实现
     */
    public List<Student> SearchStident(String sname, String sgender) throws SQLException {
        DetachedCriteria detachedCriteria = DetachedCriteria.forClass(Student.class);
        Object[] obj = { null, "男", "女" };
        detachedCriteria.add(Restrictions.like("sname", "%" + sname + "%"));
        detachedCriteria.add(Restrictions.in("gender", obj));

        Session session = HibernateUtils.oppenSession();
        Transaction transaction = session.beginTransaction();

        Criteria criteria = detachedCriteria.getExecutableCriteria(session);
        List<Student> list = criteria.list();

        transaction.commit();
        session.close();
        return list;
    }

    @Override
    /**
     * 分页查询，查询当前页的学生数据并封装成集合
     */
    public List<Student> findStudentByPage(int currentPage) throws SQLException {
        Session session = HibernateUtils.oppenSession();
        Transaction transaction = session.beginTransaction();
        Criteria criteria = session.createCriteria(Student.class);
        criteria.setFirstResult(PAGE_SIZE * (currentPage - 1));//起始位置
        criteria.setMaxResults(PAGE_SIZE);//每页多少条记录
        List<Student> list = criteria.list();
        return list;
        /*QueryRunner runner = new QueryRunner(JDBCUtil02.getDataSource());
        // 第一个？返回记录数量，第二个？偏移量
        // 第n页 ： 5,5*n-1
        return runner.query("select * from students limit ? offset ?", new BeanListHandler<Student>(Student.class),
                PAGE_SIZE, PAGE_SIZE * (currentPage - 1));*/
    }

    @Override
    /**
     * 查询学生记录数
     */
    public int findCount() throws SQLException {
        Session session = HibernateUtils.oppenSession();
        Transaction transaction = session.beginTransaction();
        Criteria criteria = session.createCriteria(Student.class);
        criteria.setProjection(Projections.rowCount());
        Long num = (Long) criteria.uniqueResult();
        return num.intValue();
    }

}