各类查询方式

//HQL查询  【适合有数据库基础的】
 @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，查询所有
  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();
 }
 

 //QBC查询  , query by criteria  彻底面向对象的查询
 @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));
  // 查询所有
  List<Employee> list = criteria.list();
  
  System.out.println(list);
  
  tx.commit();
  session.close();
 }
 
 //sQL
 @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();
 }
}