Hibernate提供的各种查询方式

一：HQL查询

二：Criteria查询（Query by Criteria）

三：本地SQL查询

public class TestHibernateQuery {

private static SessionFactory sf;
static  {

// 创建sf对象
sf = new Configuration().configure().buildSessionFactory();
}

<span style="color:#cc0000;">//HQL查询  【适合有数据库基础的】</span>
@Test
public void testQuery() throws Exception {

Session session = sf.openSession();
Transaction tx = session.beginTransaction();

// 主键查询
//Employee emp = (Employee) session.get(Employee.class, 1);

// HQL查询，查询全部
Query q = session.createQuery("from Employee where empId=1 or empId=2");
List<Employee> list = q.list();

System.out.println(list);

tx.commit();
session.close();
}

<span style="color:#cc0000;">//QBC查询  , query by criteria  完全面向对象的查询</span>
@Test
public void testQBC() throws Exception {
Session session = sf.openSession();
Transaction tx = session.beginTransaction();

Criteria criteria = session.createCriteria(Employee.class);
// 条件
criteria.add(Restrictions.eq("empId", 1));
// 查询全部
List<Employee> list = criteria.list();

System.out.println(list);

tx.commit();
session.close();
}

<span style="color:#cc0000;">//sQL</span>
@Test
public void testSQL() throws Exception {
Session session = sf.openSession();
Transaction tx = session.beginTransaction();

// 把每一行记录封装为对象数组，再添加到list集合
//		SQLQuery sqlQuery = session.createSQLQuery("select * from employee");
// 把每一行记录封装为 指定的对象类型
SQLQuery sqlQuery = session.createSQLQuery("select * from employee").addEntity(Employee.class);
List list = sqlQuery.list();

System.out.println(list);

tx.commit();
session.close();
}
}